Journal articles on the topic 'Gigabit communications Data transmission systems Optical data processing'

AbstractFuture devices for the Internet of Things will require communication systems that can deliver higher data rates at low power. Backscatter radio—in which wireless communication is achieved via reflection rather than radiation—is a low-complexity approach that requires a minimal number of active elements. However, it is typically limited to data rates of hundreds of megabits per second because of the low frequency bands used and the modulation techniques involved. Here we report a millimetre-wave modulator and antenna array for backscatter communications at gigabit data rates. This radiofrequency front-end consists of a microstrip patch antenna array and a single pseudomorphic high-electron-mobility transistor that supports a range of modulation formats including binary phase shift keying, quadrature phase shift keying and quadrature amplitude modulation. The circuit is additively manufactured with inkjet printing using silver nanoparticle inks on a flexible liquid-crystal polymer substrate. A millimetre-wave transceiver is also designed to capture and downconvert the backscattered signals and route them for digital signal processing. With the system, we demonstrate a bit rate of two gigabits per second of backscatter transmission at millimetre-wave frequencies of 24–28 GHz, and with a front-end energy consumption of 0.17 pJ per bit.

In optical communication systems, frame synchronization is essential for subsequent operations, such as error correction and payload extraction. Various methods, so far, have been proposed in the published literature, but the performance is unsatisfactory under high bit error rate (BER) conditions. We present, in this work, a novel data-aided frame synchronization technique for optical packet transmission systems, in which the transmitter sends a sequence of packets with a specific synchronization word periodically inserted, and the receiver blindly recognizes the synchronization word to attain frame synchronization. The proposed algorithm detects the synchronization word based on Hough transform (HT), a classic method for line detection in digital image processing. The core principle of the algorithm is to exploit the periodicity of the frame synchronization word, which appears as black-and-white spaced stripes on a binary image when the frames are all aligned. Simulations are conducted over a 56Gbps optical QPSK transmission system, and the results show that our algorithm is still effective in attaining frame synchronization at a BER of 0.3. A comparison is also made between our algorithm and existed autocorrelation (AC)-based algorithm. The results demonstrate that our algorithm has a better error resilience performance. When the BER is higher than 0.03, our algorithm outperforms an AC-based algorithm significantly.

Coherent optical fiber communications for data rates of 100Gbit/s and beyond have recently been studied extensively primarily because high sensitivity of coherent receivers could extend the transmission distance. Spectrally efficient modulation techniques such as M-ary quadrature amplitude modulation (M-QAM) can be employed for coherent optical links. The integration of multi-level modulation formats based on coherent technologies with wavelength-division multiplexed (WDM) systems is key to meet the aggregate bandwidth demand. This paper reviews coherent 16 quadrature amplitude modulation (16QAM) systems to scale the network capacity and maximum reach of current optical communication systems to accommodate traffic growth. Full Text: PDF ReferencesK. Kikuchi, "Fundamentals of Coherent Optical Fiber Communications", J. Lightwave Technol., vol. 34, no. 1, pp. 157-179, 2016. CrossRef S. Tsukamoto, D.-S. Ly-Gagnon, K. Katoh, and K. Kikuchi, "Coherent Demodulation of 40-Gbit/s Polarization-Multiplexed QPSK Signals with16-GHz Spacing after 200-km Transmission", Proc. OFc, Paper PDP29, (2005). DirectLink K. Kikuchi, "Coherent Optical Communication Technology", Proc. OFC, Paper Th4F.4, (2015). CrossRef J. M. Kahn and K.-P. Ho, "Spectral efficiency limits and modulation/detection techniques for DWDM systems", IEEE J. Sel. Topics Quantum Electron., vol. 10, no. 2, pp. 259–272, (2004). CrossRef S. Tsukamoto, K. Katoh, and K. Kikuchi, "Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing", IEEE Photon. Technol. Lett., vol. 18, no. 10, pp. 1131–1133, (2006). CrossRef Y. Mori, C. Zhang, K. Igarashi, K. Katoh, and K. Kikuchi, "Unrepeated 200-km transmission of 40-Gbit/s 16-QAM signals using digital coherent receiver", Opt. Exp., vol. 17, no. 32, pp. 1435–1441, (2009). CrossRef H. Nakashima, Et al., "Digital Nonlinear Compensation Technologies in Coherent Optical Communication Systems", Proc. OFC, Paper W1G.5, (2017). CrossRef S. J. Savory, "Digital filters for coherent optical receivers", Opt. Exp., vol. 16, no. 2, pp. 804–817, (2008). CrossRef D. S. Millar, T. Koike-Akino, S. Ö. Arık, K. Kojima, K. Parsons, T. Yoshida, and T. Sugihara, "High-dimensional modulation for coherent optical communications systems", Opt. Express, vol. 22, no. 7, pp 8798-8812, (2014). CrossRef R. Griffin and A. Carter, "Optical differential quadrature phase-shift key (oDQPSK) for high capacity optical transmission", Proc. OFC, Paper WX6, (2002). DirectLink K. Kikuchi, "Digital coherent optical communication systems: fundamentals and future prospects", IEICE Electron. Exp., vol. 8, no. 20, pp. 1642–1662, (2011). CrossRef F. Derr, "Optical QPSK transmission system with novel digital receiver concept", Electron Lett., vol. 27, no. 23, pp. 2177–2179, (1991). CrossRef R. No’e, "Phase noise tolerant synchronous QPSK receiver concept with digital I&Q baseband processing", Proc. OECC, Paper 16C2-5, (2004). DirectLink D.-S. Ly-Gagnon, S. Tsukamoto, K. Katoh, and K. Kikuchi, "Coherent detection of optical quadrature phase-shift keying signals with carrier phase estimation", J. Lightw. Technol., vol. 24, no. 1, pp. 12–21, (2006). CrossRef M. Taylor, "Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments", IEEE Photon. Technol. Lett., vol. 16, no. 2, pp. 674–676, (2004). CrossRef S. Tsukamoto, K. Katoh, and K. Kikuchi, "Unrepeated transmission of 20-Gb/s optical quadrature phase-shift-keying signal over 200-km standard single-mode fiber based on digital processing of homodyne-detected signal for Group-velocity dispersion compensation", IEEE Photon. Technol. Lett., vol. 18, no. 9, pp. 1016–1018, (2006). CrossRef S. Tsukamoto, Y. Ishikawa, and K. Kikuchi, "Optical Homodyne Receiver Comprising Phase and Polarization Diversities with Digital Signal Processing", Proc. ECOC, Paper Mo4.2.1, (2006). CrossRef K. Kikuchi and S. Tsukamoto, "Evaluation of Sensitivity of the Digital Coherent Receiver", J. Lightw. Technol., vol. 20, no. 13, pp. 1817–1822, (2008). CrossRef S. Ishimura and K. Kikuchi, "Multi-dimensional Permutation Modulation Aiming at Both High Spectral Efficiency and High Power Efficiency", Proc. OFC/NFOEC, Paper M3A.2, (2014). CrossRef F. I. El-Nahal and A. H. M. Husein, "Radio over fiber access network architecture employing RSOA with downstream OQPSK and upstream re-modulated OOK data", (Optik) Int. J. Light Electron Opt., vol. 123, no. 14, pp: 1301-1303, (2012). CrossRef T. Koike-Akino, D. S. Millar, K. Kojima, and K. Parsons, "Eight-Dimensional Modulation for Coherent Optical Communications", Proc. ECOC, Paper Tu.3.C.3, (2013). DirectLink B. Sklar, Digital communications: Fundamentals and Applications, Prentice-Hall, (2001).

Nowadays the technological advancement of the information transmission is developing very rapidly and it becomes necessary to achieve a high speed in the transmission of data as well as higher data rate. Developments in optical communication systems address these needs. However, despite all the features and advantages of optical communication systems, the dispersion is still the main challenges. In this paper and to this end, fiber Bragg grating (FBG) is used in order to overcome the dispersion issue in the wavelength division multiplexing (WDM) transmission system. The WDM transmission system is simulated using the advanced tools of Optisystem 13. The simulation program was used at a speed of 15 Gbits/s with 50Km optical fiber length based on the different input design parameters such as input signal power, optical fiber length and attenuation coefficient. In addition, the output performance parameters are discussed in terms of quality factor (Q-factor) and eye diagram. Moreover, a comparison between the proposed design and previous related works is presented.

Recently, neuromorphic sensors, which convert analogue signals to spiking frequencies, have been reported for neurorobotics. In bio-inspired systems these sensors are connected to the main neural unit to perform post-processing of the sensor data. The performance of spiking neural networks has been improved using optical synapses, which offer parallel communications between the distanced neural areas but are sensitive to the intensity variations of the optical signal. For systems with several neuromorphic sensors, which are connected optically to the main unit, the use of optical synapses is not an advantage. To address this, in this paper we propose and experimentally verify optical axons with synapses activated optically using digital signals. The synaptic weights are encoded by the energy of the stimuli, which are then optically transmitted independently. We show that the optical intensity fluctuations and link’s misalignment result in delay in activation of the synapses. For the proposed optical axon, we have demonstrated line of sight transmission over a maximum link length of 190 cm with a delay of 8 μs. Furthermore, we show the axon delay as a function of the illuminance using a fitted model for which the root mean square error (RMS) similarity is 0.95.

The increase of data-rates that are provided by free-space optical (FSO) communications is essential in our data-driven society. When used in satellite and interplanetary networks, these optical links can ensure fast connections, yet they are susceptible to atmospheric disruptions and long orbital delays. The Delay and Disruption Tolerant Networking (DTN) architecture ensures a reliable connection between two end nodes, without the need for a direct connection. This can be an asset when used with FSO links, providing protocols that can handle the intermittent nature of the connection. This paper provides a review on the theoretical and state-of-the-art studies on FSO and DTN. The aim of this review is to provide motivation for the research of an optical wireless satellite network, with focus on the use of the Licklider Transmission Protocol. The assessment presented establishes the viability of these networks, providing many examples to rely on, and summarizing the most recent stage of the development of the technologies addressed.

This paper presents a Filter Bank Multicarrier (FBMC), a viable waveform candidate for fifth generation (5G) communications using Staggered-Modulated Multitone (SMT). FBMC is preferred in optical communication because of its ability to work without Cyclic Prefix (CP). In any case, the operation of FBMC in optical access systems with Artificial Neural Networks (ANNs) has not been broadly explored either downstream or upstream. This work presents an advanced Nonlinear Feed-Forward Equalizer (NFFE) that makes use of multilayer ANN for dispersion compensation. ANN is trained to act as a filter with an extensive equalizer training which has the ability to mitigate dispersion and increase the performance of the system. The simulation work is used to study the performance of intensity modulated FBMC system with direct detection in Long Reach-Passive Optical Networks (LR-PONs).The transmission data rate is varied between 8 and 10[Formula: see text]Gbps with the optical fiber length from 30 to 90[Formula: see text]km of Standard Single Mode Fiber (SSMF). The obtained result suggests that FBMC system with ANN-NFFE equalizer fundamentally builds the resilience to the Chromatic Dispersion (CD) distortion, and a CP-less transmission is possible upto 90[Formula: see text]km.

Facing the growing high data rate and large communication capacity demands, optical communications are widely recognized to be used to implement satellite communications. For a space-based optical backbone network, an appropriately designed protocol stack is important. In this paper, we proposed a protocol stack that is suitable for a space-based optical backbone network. Following this, we then used software to simulate this stack, built a hardware platform to test it, and finally, analyzed the results. The results showed that the proposed protocol stack was well designed to provide efficient control and management of the space-based optical backbone network. It could improve management efficiency by collecting resources and automatically calculating and building route paths. It could also facilitate data forwarding in intermediate satellite nodes with limited source and power, by using an advanced orbiting systems (AOS) frame switching scheme to avoid unnecessary processes, such as unpacking, upper-layer processing and repacking for passing services. The protocol stack could also support the use of unidirectional links to improve the link resource utilization. Finally, it could also provide transparent transmission for different kinds of services.

As a promising approach to implement indoor positioning, visible light positioning (VLP) based on optical camera communication (OCC) image sensor has attracted substantial attention. However, the decoding schemes of existing VLP systems still face many challenges. First, the transmission channel between transmitters and receivers can be easily affected by environmental changes, resulting in poor thresholding performance. Second, the inherently unsynchronized air transmission channel issue remains a big obstacle for decoding data. The above two problems limit the application of VLP systems, where various mobile devices are used as receivers and the properties of transmission channel are constantly changing with the movement of receivers. In this paper, a universal and effective decoding scheme named pixel-to-bit calculation (PBC) decoding algorithm for VLP systems is proposed and experimentally demonstrated. It includes a Staged Threshold Scheme which provides excellent thresholding performance for different transmission channel conditions, as well as a Synchronous Decoding Operation to automatically synchronize the clock between transmitters and receivers. A decoding rate of 95.62% at the height of 2.73 m is realized in a practical Robotic-based VLP system embedded with our proposed PBC decoding scheme. In addition, experimental results show that the average decoding rate of the proposed PBC decoding scheme reaches 99.9% when applying different transmitters and receivers.

Nonlinear effects in the optical transmission systems (OTSs) are considered as the major performance limiting factor to provide high transmission rates over ultra-long distances. As the demands for system capacity, transmission range and the number of users is increasing exponentially with the development of mobile broadband, new challenges are being faced by the backbone optical networks. Mainly, the refractive index related non-linearities (RIrNLs) need to be characterized to design an optimal OTS for error-free transmission with provision of wavelength division multiplexing (WDM) to support for multiple channels. This paper provides an estimation technique of RIrNLs for long-haul transmission and their treatment for different channel spacing and the number of channels in a WDM system operating frequency domain multiple in multiple out (FD-MIMO) equalizer based digital signal processing (DSP) receiver and microstrip Chebyshev low pass filter. The main focus of this work is to utilize the existing structure of OTS for RIrNLs treatment with a low cost solution. Thus, by varying the parameters of the third order dispersion parameters, group velocity dispersion parameters, phase modulation dispersion and nonlinear refractive index, the impact of RIrNLs is investigated in detail to enhance the transmission range and capacity of the current OTS. The proposed system is analyzed in terms of range of input power, fiber length and received power for OTS figure of merits including bit error rate (BER) and optical signal-to-noise ratio (OSNR). Using duo-binary modulation, the BER achieved in this work is <10−5 till 500 km range, for maximum number of 32 channels, with 100 Gbps aggregate data rate, which shows the feasibility and effectiveness of our proposed model.

Recently, digital displays and cameras have been extensively used as new data transmission and reception devices in conjunction with optical camera communication (OCC) technology. This paper presents three types of frequency-based data-embedding mechanisms for a display-to-camera (D2C) communication system, in which a commercial digital display transmits information and an off-the-shelf smartphone camera receives it. For the spectral embedding, sub-band coefficients obtained from a discrete cosine transform (DCT) image and predetermined embedding factors of three embedding mechanisms are used. This allows the data to be recovered from several types of noises induced in wireless optical channels, such as analog-to-digital (A/D) and digital-to-analog (D/A) conversion, rotation, scaling, and translation (RST) effects, while also maintaining the image quality to normal human eyes. We performed extensive simulations and real-world D2C experiments using several performance metrics. Through the analysis of the experimental results, it was shown that the proposed method can be considered as a suitable candidate for the D2C system in terms of the achievable data rate (ADR), peak signal-to-noise ratio (PSNR), and the bit error rate (BER).

In this work, we present the design, laboratory tests, and the field trial results of a power-over-fiber (PoF) low power instrument transformer (LPIT) for voltage and current measurements in the medium voltage distribution networks. The new proposed design of this power-over-fiber LPIT aims to overcome the drawbacks presented by the previous technologies, such as the continuous operation (measuring and data transmission) for a wide current range conducted in the medium voltage transmission lines, damage due to lightning strikes, accuracy dependency on vibration, position and temperatures. The LPIT attends the accuracy criteria of IEC 61869-10 and IEC 61869-11 in terms of current and voltage accuracy and it attends the practical criteria adopted by Utilities companies including voltage measurements without removing the coating of the covered conductors. The PoF based LPIT was developed to be applied at 11.9 kV, 13.8 kV, and 23.0 kV phase-to-phase nominal voltages, and in two current ranges 1.25–30 A and 37.5–900 A. The digital data transmission of current, voltage, and temperature from the sensing unit to the processing unit uses a special synchronism technique and it is performed by two 62.5 µm multimode fibers in 850 nm. The optical powering in 976 nm is also performed by one 62.5 µm multimode fiber from the processing unit to the sensor unit. We presented all details of the sensor design and its laboratory characterization in terms of accuracy and temperature correction. We also presented the results of field tests of the sensor made in two different conditions: in a standard distribution network and an experimental hybrid fiber/power distribution network. We believe that these studies aim to incorporate optical fiber and devices, digital technologies, communications systems in electrical systems driving their evolution.

AbstractThe explosive growth of data centers, cloud computing and various smart devices is limited by the current state of microelectronics, both in terms of speed and heat generation. Benefiting from the large bandwidth, promising low power consumption and passive calculation capability, experts believe that the integrated photonics-based signal processing and transmission technologies can break the bottleneck of microelectronics technology. In recent years, integrated photonics has become increasingly reliable and access to the advanced fabrication process has been offered by various foundries. In this paper, we review our recent works on the integrated optical signal processing system. We study three different kinds of on-chip signal processors and use these devices to build microsystems for the fields of microwave photonics, optical communications and spectrum sensing. The microwave photonics front receiver was demonstrated with a signal processing range of a full-band (L-band to W-band). A fully integrated microwave photonics transceiver without the on-chip laser was realized on silicon photonics covering the signal frequency of up 10 GHz. An all-optical orthogonal frequency division multiplexing (OFDM) de-multiplier was also demonstrated and used for an OFDM communication system with the rate of 64 Gbps. Finally, we show our work on the monolithic integrated spectrometer with a high resolution of about 20 pm at the central wavelength of 1550 nm. These proposed on-chip signal processing systems potential applications in the fields of radar, 5G wireless communication, wearable devices and optical access networks.

Radio over fiber (RoF) can be assessed as a system of most convenient combination of optical fiber and radio signals. The technique of orthogonal frequency division multiplexing (OFDM) considers as a data distribution over a huge number of carriers having spaced from each other with specific frequencies at overlap bands. Hence incorporates OFDM with the optical fiber, OFDM-RoF system can be increased the modulation RF access capacity besides high-speed data transmission, it considers a broadband communication trend of the current and future applications specifically for 5G mobile. The optical network scenarios of various RF can be model with optisystem software, and OFDM in addition to use a section of the orthogonal multiplex frequency of 16-quadrature amplitude modulation (QAM) RF modulating signal. In the optical domain, Mach-Zehnder modulator (MZM) optical modulators are used to carry out different results with different fiber lengths. An OFDM-RoF wireless communication system considers as advanced data rate transmission achievement by minimum delays. The essential goal of this paper is for identifying the minimum bit error rate (BER) for the 16-QAM modulation with varying fiber length. The OFDM-RoF system can be able for realizing a fiber length 100 km with a restricted decreasing in the received power so that the constellation noise is became greater despite of applying electrical amplification and optical amplification.

<p>The study outlined the soliton pulse order effects on the performance efficiency of the optical transceiver systems. The power after fiber is reported for various Soliton pulse order. Max optical signal power (SP) and min optical noise power (NP) are clarified versus time after optical fiber for various soliton pulse order. As well as the max electrical power amplitude against time period is demonstrated after electrical filter for various soliton pulse order. It is reported that the optical transceiver performance efficiency can be upgraded with the first soliton order pulse. The soliton technique is used for high speed communication transmission systems. Soliton technique is used to compensate the dispersion and balanced with nonlinear effects. The soliton order effects is then discussed to choose the suitable soliton order for high speed system performance efficiency. The soliton techniques can be used also for extended ultra high transmion distance with high data rates.</p>

Visible light communications (VLC) have received significant attention as a way of moving part of the saturated indoor wireless traffic to the wide and unregulated visible optical spectrum. Nowadays, VLC are considered as a suitable technology, for several applications such as high-rate data transmission, supporting internet of things communications or positioning. The signal processing originally derived from radio-frequency (RF) systems such as cooperative or precoding schemes can be applied to VLC. However, its implementation is not straightforward. Furthermore, unlike RF transmission, VLC present a predominant line-of-sight link, although a weak non-LoS component may appear due to the reflection of the light on walls, floor, ceiling and nearby objects. Blocking effects may compromise the performance of the aforementioned transmission schemes. There exist several surveys in the literature focused on VLC and its applications, but the management of the shadowing and interference in VLC requires a comprehensive study. To fill this gap, this work introduces the implementation of cooperative and precoding schemes to VLC, while remarking their benefits and drawbacks for overcoming the shadowing effects. After that, the combination of both cooperative and precoding schemes is analyzed as a way of providing resilient VLC networks. Finally, we propose several open issues that the cooperative and precoding schemes must face in order to provide satisfactory VLC performance in indoor scenarios.

(1) Background: Free space optics communication (FSO) has improved wireless communication and data transfer thanks to high bandwidth, low power consumption, energy efficiency, a high transfer capacity, and a wide applicability field. The FSO systems also have their limitations, including weather conditions and obstacles in the way of transmission. (2) Methods: This research assesses the atmospheric conditions’ influence on the intensity of received radiation, both experimentally and theoretically. The construction of a laboratory test stand of the FSO system, which is operating in the third-atmosphere transmission window (8–12 µm), is proposed. Next, considering different atmospheric conditions, the experimental validation was conducted, both in a laboratory and real conditions. (3) Results: The measurements were carried out for two optical links working with wavelengths of 1.5 µm and 10 µm. It was found that optical radiation with a wavelength of about 10 µm is characterized by better transmission properties in the case of limited visibility (e.g., light rain and fogs) than in the case of near-infrared waves. The same conclusion was found in analytical investigations. (4) Conclusions: The results obtained show that optical radiation with a wavelength of about 10 µm in limited visibility is characterized by better transmission properties than near-infrared waves. This demonstrates the validity of designing FSO links operating in the range 8–12 µm band, e.g., based on quantum cascade lasers and HgCdTe photodiodes.

With the ever-increasing demand for bandwidth, appropriate mechanisms that would provide reliable and optimum service level to designated or specified traffic classes during heavy traffic loads in networks are becoming particularly sought after. One of these mechanisms is the resource reservation mechanism, in which parts of the resources are available only to selected (pre-defined) services. While considering modern elastic optical networks (EONs) where advanced data transmission techniques are used, an attempt was made to develop a simulation program that would make it possible to determine the traffic characteristics of the nodes in EONs. This article discusses a simulation program that has the advantage of providing the possibility to determine the loss probability for individual service classes in the nodes of an EON where the resource reservation mechanism has been introduced. The initial assumption in the article is that a Clos optical switching network is used to construct the EON nodes. The results obtained with the simulator developed by the authors will allow the influence of the introduced reservation mechanism on the loss probability of calls of individual traffic classes that are offered to the system under consideration to be determined.

Recently, research on sixth-generation (6G) networks has gained significant interest. 6G is expected to enable a wide-range of applications that fifth-generation (5G) networks will not be able to serve reliably, such as tactile Internet. Additionally, 6G is expected to offer Terabits per second (Tbps) data rates, 10 times lower latency, and near 100% coverage, compared to 5G. Thus, 6G is expected to expand across all available spectrums including terahertz (THz) and optical frequency bands. In this manuscript, mixed-carrier communication (MCC) is investigated as a novel physical layer (PHY) design for 6G networks. The proposed MCC version in this study is based on visible light communication (VLC). MCC enables a unified transmission PHY design to connect devices with different complexities, simultaneously. The design trade-offs and the required signal-to-noise ratio (SNR) per individual modulation schemes embedded within MCC are investigated. The complexity analysis shows that a conventional optical OFDM receiver can capture the high-speed bit-stream embedded within MCC. For a forward error correction (FEC) bit-error-rate (BER) threshold of 3.8×10−3, MCC is optimized to maximize the spectral efficiency by embedding 2-beacon phase-shift keying (2-BnPSK) within an MCC envelope on top of 12 bits per beacon position modulation (BPM) symbol.

The interconnection of many processors in order to increase the computing power of the ensemble is a growing theme in the data processing industry [1]. These processors may be within modules on a common board, on seperate boards within a common frame, or in seperate frames distributed in a room or building. A key element of this “computer complex” is the network which allows efficient data transfers. These data processing networks are differentiated from data communications networks by a demand for fast data transfer, so that the processors and memory at the nodes can interact in times measured in about 1–1000 machine cycles. Machine cycle times might be from tens to hundreds of nanoseconds, and the amount of data transferred might be measured in Kilobytes [2]. This implies both a fast and a high bandwidth technology for implementing these interconnections, as well as a limited link distance. The VLSI IC technology and associated dense electrical chip packaging which has made such powerful computing nodes possible, also implies a requirement for dense packaging of the optical link adapter, for compatability [3]. The multiprocessor complex has very high requirements on reliability, leading to low tolerance for component failure or erroneous data transmission. Eight year life, with failure rates less than 0.01%/Khr, and link bit error rates less than 1 in 1015 are not uncommon requirements [4]. The performance and cost of these networks are often determined by the wiring technology chosen, specifically the electronics and opto-electronics of the interfaces at the network's nodes. Optical interconnections are potentially attractive for this application, but the requirements on optical, electrical and associated packaging technologies are significantly different than the technology which has been developed for the data communications applications. [4, 5].

Optical fibers are utilized widely for data transmission systems because of their capacity to carry extensive information and dielectric nature. Network architectures utilizing multiple wavelengths per optical fiber are used in central, metropolitan, or broad‐area applications to link thousands of users with a vast range of transmission speeds and capacities. A powerful feature of an optical communication link is sending several wavelengths through the 1300‐to‐1600‐ nm range of a fibre simultaneously. The technology of integrating several wavelengths onto a similar fiber is called wavelength division multiplexing (WDM). The principle of WDM utilized in concurrence with optical amplifiers has an outcome in communication links that permit rapid communications among users in the world's countries. This paper presents an overview of the challenges of fibre optic communication. This paper offers an outline of the areas to be the most relevant for the future advancement of optical communications. The invention of integrated optics and modern optical fibers takes place in the field of optical equipment and components.

ABSTRACTRecently, various nanoscale materials, devices, and systems with remarkable properties have been developed, with numerous unique applications in chem.-bio sensors, nanophotonics, and nanobiotechnology. This presentation covers satellite and aerial remote sensing science and methodologies employing nanotechnology based advanced sensor systems to improve performance, resolutions, and security. Increased demand on monitoring, surveillance due to global war on terrorism, weather prediction, and environmental pollution detection and monitoring have necessitated geospatial sensing with high accuracy, speed, and authenticity. Plasmonic interactions on the nanoscale and nanophotonics have produced new phenomena and technologies surpassing the realms of possibilities with conventional photonics and electronics. These new technologies could include high spatial resolution near-field imaging, high efficiency information processing and transferring, high capacity optical data storage, flexible- and high contrast displays, and precise detection, control and manipulation of nanoscale devices and integrated systems. Elements utilizing refractive or diffractive surfaces have found applications in novel sub-wavelength nanostructures satellites. The nanophotonics structures coupled with lightweight structures and advanced nanotechnology based sensors have resulted in launching of nano-satellites by several countries. The use of nanophotonics in space through the combination of micro, nano, integrated and fibre-optic technologies is to reduce susceptibility of the system to EMI, reduction in the weight of the signal cables (< 1/20 of electrical), higher information transmission capacity (GHz), reduced weight and volume, opto-isolation of critical spacecraft subsystems, high speed optical processing of RF and microwave signals, low propagation loss, and enhanced security encryption capabilities. Carbon Nanotubes (CNTs) based field emission electron gun (FEG) employ low voltage for emission and are actively researched as cold cathode microwave generation devices. CNTs based composites provide light-weight and compact platform with mechanical and thermal robustness. Such satellite system can be placed in low Earth orbit (LEO) to medium Earth orbit (MEO) as multi-sensor satellite imagers with panchromatic, multi-spectral, area and hyper spectral sensors on a single focal plane array (FPA), to achieve medium to high resolution (2.5m to 15m) spatial sampling, wide swaths (up to 45km) and noise equivalent reflectance (NER) values of less than 0.5%. An evaluation of security risks, vulnerability, and strategies is presented for communications technologies used in gathering, processing, storing, and disseminating global environmental micro and nano sensors and satellite data.

Digital culture, as we know it, owes much to space exploration. The technological pursuit of outer space has fuelled innovations in signal processing and automated computing that have left an impact on the hardware and software that make our digital present possible. Developments in satellite technologies, for example, produced far-reaching improvements in digital image processing (Gonzalez and Woods) and the demands of the Apollo missions advanced applications of the integrated circuit – the predecessor to the microchip (Hall). All the inventive digital beginnings in space found their way back to earth and contributed to the development of contemporary formations of culture composed around practices dependent on and driven by digital technologies. Their terrestrial adoption and adaptation supported a revolution in information, mediation and communication technologies, increasing the scope and speed of global production, exchange and use of data and advancing techniques of imaging, mapping, navigation, surveillance, remote sensing and telemetry to a point that could only be imagined before the arrival of the space age. Steadily knotted with contemporary scientific, commercial and military endeavours and the fabric of the quotidian, digital devices and practices now have a bearing upon all aspects of our pursuits, pleasures and politics. Our increasing reliance upon the digital shaped the shared surfaces of human societies and produced cultures in their own right. While aware of the uneasy baggage of the term ‘culture’, we use it here to designate all digitally grounded objects, systems and processes which are materially and socially inflecting our ways of life. In this sense, we consider both what Michael Hardt and Antonio Negri describe as “those results of social production that are necessary for social interaction and further production, such as knowledges, languages, codes, information, affects, and so forth” (viii), and the material contexts of these products of the social. The effects of digital technologies on the socio-material ambits of human life are many and substantial and – as we want to suggest here – evolving through their ‘extraterrestrial’ beginnings. The contemporary courses of digital cultures not only continue to develop through investments in space exploration, they are themselves largely contingent on the technologies that we have placed in outer space, for instance, global telecommunications infrastructure, GPS, Google maps, weather and climate monitoring facilities and missile grids all rely on the constellation of satellites orbiting the earth. However, we have been increasingly witnessing something new: modes of social production that developed on earth from the technical demands of the space age are now being directed, or rather returned back to have new beginnings beyond the globe. Our focus in this paper is this outward momentum of digital cultures. We do not aim to overview the entire history of the digital in outer space, but instead to frame the extraterrestrial extension of human technologies in terms of the socio-material dimensions of extra-planetary digital cultures. Hannah Arendt described how the space age accelerated the already rapid pace of techno-scientific development, denying us pause during which to grasp its effects upon the “human condition”. Our treacherously fast technological conquest of outer space leaves in its wake an aporia in language and “the trouble”, as Arendt puts it, is that we will “forever be unable to understand, that is, to think and speak about the things which nevertheless we are able to do” (3). This crisis in language has at its core a problem of ontology: a failure to recognise that the words we use to describe ourselves are always, and have always been, bound up in our technological modes of being. As thinkers such as Gilbert Simondon and Bernard Stiegler argued and Arendt derided (but could not deny), our technologies are inseparably bound up with the evolutionary continuum of the human and the migration of our digital ways of life into outer space still further complicates articulation of our techno-logic condition. In Stiegler’s view the technical is the primordial supplement to the human into which we have been “exteriorising” our “interiors” of social memory and shared culture to alter, assert and advance the material-social ambits of our living milieu and which have been consequently changing the idea of what it is to be human (141). Without technologies – what Stiegler terms “organised inorganic matter” (17), which mediate our relationships to the world – there is no human in the inhuman extraterrestrial environment and so, effectively, it is only through the organisation of inert matter that culture or social life can exist outside the earth. Offering the possibility of digitally abstracting and processing the complexities and perils of outer space, space technologies are not only a means of creating a human milieu ‘out there’, but of expediting potentially endless extra-planetary progress. The transposition of digital culture into outer space occasions a series of beginnings (and returns). In this paper, we explore extra-planetary digital culture as a productive trajectory in broader discussions of the ontological status of technologies that are socially and materially imbricated in the idea of the human. We consider the digital facilitation of exchanges between earth and outer space and assign them a place in an evolving discourse concerned with expressing the human in relation to the technological. We suggest that ontological questions occasioned by the socio-material effects of technologies require consideration of the digital in outer space and that the inhuman milieu of the extraterrestrial opens up a unique perspective from which to consider the nascent shape of what might be the emerging extra-planetary beginnings of the post human. Digital Exurbias The unfolding of extra-planetary digital cultures necessitates the simultaneous exteriorisation of our production of the social into outer space and the domestication of our extraterrestrial activities here on earth. Caught in the processes of mediated exploration, the moon, Mars, Pluto and other natural or human-made celestial bodies such as the International Space Station are almost becoming remote outer suburbs – exurbias of earth. Digital cultures are reaching toward and expanding into outer space through the development of technologies, but more specifically through advancing the reciprocal processes of social exchanges between terrestrial and extraterrestrial space. Whether it be through public satellite tracking via applications such as Heavens-Above or The High Definition Earth Viewing system’s continuous video feed from the camera attached to the ISS (NASA, "High Definition") – which streams us back an image of our planetary habitat from an Archimedean point of view – we are being encouraged to embrace a kind of digital enculturation of extraterrestrial space. The production of social life outside our own planet has already had many forms, but perhaps can be seen most clearly aboard the International Space Station, presently the only extraterrestrial environment physically occupied by humans. Amongst its many landmark events, the ISS has become a vigorous node of social media activity. For example, in 2013 Chris Hadfield became a Twitter phenomenon while living aboard the ISS; the astronaut gathered over a million Twitter followers, he made posts on Facebook, Tumblr and Reddit, multiple mini-vids, and his rendition of David Bowie’s Space Oddity on YouTube (Hadfield) has thus far been viewed over 26 million times. His success, as has been noted, was not merely due to his use of social media in the unique environment of outer space, but rather that he was able to make the highly technical lives of those in space familiar by revealing to a global audience “how you make a sandwich in microgravity, how you get a haircut” (Potter). This techno-mediation of the everyday onboard ISS is, from a Stieglerian perspective, a gesture toward the establishment of “the relation of the living to its milieu” (49). As part of this process, the new trends and innovations of social media on earth are, for example, continuously replayed and rehearsed in the outer space, with a litany of ‘digital firsts’ such as the first human-sent extraterrestrial ‘tweet’, first Instagram post, first Reddit AMA and first Pinterest ‘pin’ (Knoblauch), betraying our obsessions with serial digital beginnings. The constitution of an extra-planetary milieu progresses with the ability to conduct real-time interactions between those on and outside the earth. This, in essence, collapses all social aspects of the physical barrier and the ISS becomes merely a high-tech outer suburb of the globe. Yet fluid, uninterrupted, real-time communications with the station have only just become possible. Previously, the Iinternet connections between earth and the ISS were slow and troublesome, akin to the early dial-up, but the recently installed Optical Payload for Lasercomm Science (OPAL), a laser communications system, now enables the incredible speeds needed to effortlessly communicate with the human orbital outpost in real-time. After OPAL was affixed to the ISS, it was first tested using the now-traditional system test, “hello, world” (NASA, "Optical Payload"); referencing the early history of digital culture itself, and in doing so, perhaps making the most apt use of this phrase, ever. Open to Beginnings Digital technologies have become vital in sustaining social life, facilitating the immaterial production of knowledge, information and affects (Hardt and Negri), but we have also become increasingly attentive to their materialities; or rather, the ‘matter of things’ never went away, it was only partially occluded by the explosion of social interactivities sparked by the ‘digital revolution’. Within the ongoing ‘material turn’, there have been a gamut of inquiries into the material contexts of the ‘digital’, for example, in the fields of digital anthropology (Horst and Miller), media studies (Kirschenbaum, Fuller, Parikka) and science and technology studies (Gillespie, Boczkowski, and Foot) – to mention only a very few of these works. Outside the globe material things are again insistent, they contain and maintain the terrestrial life from which they were formed. Outer space quickens our awareness of the materiality underpinning the technical apparatus we use to mediate and communicate and the delicate support that it provides for the complex of digital practices built upon it. Social exchanges between earth and its extra-planetary exurbias are made possible through the very materiality of digital signals within which these immaterial interactions can take place. In the pared down reality of contemporary life in outer space, the sociality of the digital is also harnessed to bring forth forms of material production. For example, when astronauts in space recently needed a particular wrench, NASA was able to email them a digital file from which they were then able print the required tool (Shukman). Through technologies such as the 3D printer, the line between products of the social and the creation of material objects becomes blurred. In extra-planetary space, the ‘thingness’ of technologies is at least as crucial as it is on earth and yet – as it appears – material production in space might eventually rely on the infrastructures occasioned by the immaterial exchanges of digital culture. As technical objects, like the 3D printer, are evolving so too are conceptions of the relationship that humans have with technologies. One result of this is the idea that technologies themselves are becoming capable of producing social life; in this conception, the relationships and interrelationships of and with technologies become a potential field of study. We suggest here that the extra-planetary extension of digital cultures will not only involve, but help shape, the evolution of these relationships, and as such, our conceptions and articulations of a future beyond the globe will require a re-positioning of the human and technical objects within the arena of life. This will require new beginnings. Yet beginnings are duplicitous, as Maurice Blanchot wrote – “one must never rely on the word beginning”; technologies have always been part of the human, our rapport is in some sense what defines the human. To successfully introduce the social in outer space will involve an evolution in both the theory and practice of this participation. And it is perhaps through the extra-planetary projection of digital culture that this will come about. In outer space the human partnership with the objects of technology, far from being a utopian promise or dystopian end, is not only a necessity but also a productive force shaping the collective beginnings of our historical co-evolution. Objects of technology that migrate into space appear designed to smooth the ontological misgivings that might arise from our extra-planetary progress. While they are part of the means for producing the social in outer space and physical fortifications against human frailty, they are perhaps also the beginnings of the extraterrestrial enculturation of technologies, given form. One example of such technologies is the anthropomorphic robots currently developed by the Dextrous Robotics Laboratory for NASA. The latest iteration of these, Robotnaut 2 was the first humanoid robot in space; it is a “highly dexterous” robot that works beside astronauts performing a wide range of manual and sensory activities (NASA, "Robonaut"). The Robonaut 2 has recorded its own series of ‘firsts’, including being the “first robot inside a human space vehicle operating without a cage, and first robot to work with human-rated tools in space” (NASA, "Robonaut"). One of the things which mark it as a potential beginning is this ability to use the same tools as astronauts. This suggests the image of a tool using a tool – at first glance, something now quite common in the operation of machines – however, in this case the robot is able to manipulate a tool that was not designed for it. This then might also include the machine itself in our own origins, in that evolutionary moment of grasping a tool or stealing fire from the gods. As an exteriorisation of the human, these robots also suggest that a shared extra-planetary culture would involve acknowledging the participation of technologic entities, recognising that they share these beginnings with us, and thus are participating in the origins of our potential futures beyond the globe – the prospects of which we can only imagine now. Identifiably human-shaped, Robonauts are created to socialise with, and labour together with, astronauts; they share tools and work on the same complex tasks in the same environment aboard the International Space Station. In doing so, their presence might break down the separation between the living and the nonliving, giving form to Stiegler’s hypothesis regarding the ontology of technical objects, and coming to represent a mode of “being” described as “organized inert matter” (49). The robonaut is not dominated by the human, like a hand-held tool, nor is it dominating like a faceless system; it is engineered to be conducted, ‘organised’ rather than controlled. In addition to its anthropomorphic tendencies – which among other things, makes them appear more human than astronauts wearing space suits – is the robonaut’s existence as part of an assemblage of networked life that links technical objects with wet bodies into an animate system of information and matter. While this “heralds the possibility of making the technical being part of culture” (Simondon 16), it also suggests that extra-planetary digital cultures will harness what Simondon formulates as an “ensemble” of “open machines” – a system of sensitive technologies toward which the human acts as “organizer and as a living interpreter” (13). In the design of our extra-planetary envoys we are evolving toward this openness; the Robonaut, a technical object that shares in digital culture and its social and material production, might be the impetus through which the human and technological acquire a language that expresses a kind of evolutionary dialectic. As a system of inclusions that uses technologies to incorporate/socialise everything it can, including its own relationship with technical objects, digital culture in outer space clarifies how technologies might relate and “exchange information with each other through the intermediacy of the human interpreter” (Simondon 14). The Robonaut, like the tweeting astronaut, provides the test signals for what might eventually become points of communication between different modes of being. In this context, culture is collective cumulative memory; the ‘digital’ form of culture suggests an evolution of both technologic life and human life because it incorporates the development of more efficient means of storing and transmitting memory as cultural knowledge, while recognising the experience of both. Social learning and memory will first define the evolution of the Robonaut. Digital culture and the social expressed through technology – toward a shared social life and cultural landscape established in outer space – will involve the conservation, transmission and setting of common patterns that pool a composite interplay of material, neurobiologic and technologic variables. This will in turn require new practices of enculturation, conviviality with technologies, a sharing, incorporation and care. Only then might this transform into a discussion concerning the ontologies of the ‘we’. (Far from) Conclusions Hannah Arendt wrote that technologic progress could not find full expression in “normal” (3) language and that we must constantly be aware that our knowledge, politics, ethics and interactions with regard to technologies are incomplete, unformulated or unexpressed. It could be said then that our relationship with technologies is constantly beginning, that this need to keep finding new language to grasp it means that it actually progresses through its rehearsal of beginnings, through the need to maintain the productive inquisitive force of a pleasant first meeting. Yet Arendt’s idea emerges from a kind of contempt for technology and her implied separation between ‘normal’ and what could be called ‘technical’ language suggests that she privileges the lay ‘human’ tongue as the only one in which meaningful ideas can be properly expressed. What this fails to acknowledge is an appreciation of the potential richness of technical language and Arendt instead establishes a hierarchy that privileges one’s ‘natural’ language. The invocation of the term ‘normal’ is itself an admission of unequal relations with technologies. For a language to develop in which we can truly begin to express and understand the human relationship with ever-changing but ever-present technologies,, we must first allow the entrance of the language of technology into social life – it must be incorporated, learnt or translated. In the future, this might ultimately give technology a voice in a dialogue that might be half-composed of binary code. Digital culture is perhaps a forerunner of such a conversation and perhaps it is in the milieu of outer space that it could be possible to see advances in our ideas about the mutually co-constitutive relationship between the human and technical. 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