Gotowa bibliografia na temat „Silicon microring resonators”

Microwave photonic (MWP) signal processing has attracted strong interest due to its unique advantages such as large operational bandwidth and immunity against electromagnetic interference. Recently, fast-growing markets in 5G wireless networks and the Internet of Things have become a strong thrust to the development of MWP signal processing. They are expected to benefit from MWPs with its capabilities to achieve a high time-bandwidth product in the transmission of microwave or millimeter-wave signals. Conventional MWP systems are composed of discrete optoelectronic devices and fiber-based components, which are usually bulky and power-hungry, making them inferior to the commercial RF electronic devices. It is therefore imperative to realize compact integrated MWP systems with reduced cost, size, weight and power consumption. While Moore's Law is approaching its limit to drive the evolution of electronic circuits, the silicon photonic integration platform, which features high compatibility with the standard CMOS processes, emerges as a promising solution. By incorporating both electronics and optics components on a single integrated chip, silicon photonic circuits ensure the unique characteristics of MWP signal processing such as wide bandwidth and high configurability are fully utilized, thus promoting the performance of integrated MWP signal processors. In this thesis, the applications of integrated silicon photonics on key MWP building blocks are investigated. The investigation is focused on the applications of microring resonators fabricated on SOI platform, which exhibit excellent compactness due to their inherent resonance effect and strong light confinement of the waveguide. The MWP building blocks we explore include an integrated optical single sideband modulator, a frequency tunable microwave filter for amplitude control and a photonic-assisted microwave frequency measurement system.

This thesis presents a novel method of modulating silicon photonic circuits using 3D printed microfluidic devices. The fluids that pass through the microfluidic device interact directly with the silicon waveguides. This method changes the refractive index of the waveguide cladding, thus changing the effective index of the system. Through using this technique we demonstrate the shift in resonant wavelength by a full free spectral range (FSR) by increasing the concentration of the salt water in the microfluidic device from 0% to 10%. On a 60 μm microring resonator, this equals a resonant wavelength shift of 1.514 nm when the index of the cladding changes by 0.017 refractive index units (RIU), or at a rate of 89.05 nm/RIU. These results are confirmed by simulations that use both analytical and numerical methods. This thesis also outlines the development of a process that uses two-photon absorption(TPA) in silicon to produce a photoelectrochemical (PEC) etching effect. TPA induces free carriers in silicon that then interact with the Hydroflouric Acid (HF) solution that the wafer is submerged in. This interaction removes silicon away from the wafer, which is the etching observed in our experiments. Non-line-of-sight PEC etching is demonstrated. The optical assemblies used in these experiments are presented, as are several of the results of the etching experiments.

Optical polymers are a subject of research and industry implementation for many decades. Optical polymers are inexpensive, easy to process and flexible enough to meet a broad range of application-specific requirements. These advantages allow a development of cost-efficient polymer photonic integrated circuits for on-chip optical communications. However, low refractive index contrast between core and cladding limits light confinement in a core and, consequently, integrated polymer device miniaturization. Also, polymers lack active functionality like light emission, amplification, modulation, etc. In this work, we improved a performance of integrated polymer waveguides and demonstrated active waveguide devices. Also, we present novel Si QD/polymer optical materials. In the integrated device part, we demonstrate optical waveguides with enhanced performance. Decreased radiation losses in air-suspended curved waveguides allow low-loss bending with radii of only 15 µm, which is far better than &gt;100 µm for typical polymer waveguides. Another study shows a positive effect of thermal treatment on acrylate waveguides. By heating higher than polymer glass transition temperature, surface roughness is reflown, minimizing scattering losses. This treatment method enhances microring resonator Q factor more than 2 times. We also fabricated and evaluated all-optical intensity modulator based on PMMA waveguides doped with Si QDs. We developed novel hybrid optical materials. Si QDs are encapsulated into PMMA and OSTE polymers. Obtained materials show stable photoluminescence with high quantum yield. We achieved the highest up to date ~65% QY for solid-state Si QD composites. Demonstrated materials are a step towards Si light sources and active devices. Integrated devices and materials presented in this work enhance the performance and expand functionality of polymer PICs. The components described here can also serve as building blocks for on-chip sensing applications, microfluidics, etc.<br><p>QC 20171207</p>

A 4 × 4 photonic switch matrix was designed, fabricated and characterized. The photonic switch matrix was based on microring resonator (MR) and was fabricated on relatively low-cost silicon-on-insulator (SOI). Independent wavelength channel switching was accomplished by thermo-optic tuning of the MRs through highly localized resistive micro-heaters. The device was fabricated using the relatively mature silicon fabrication technology. Waveguide patterns were defined with high definition eBeam lithography, etching was done in a reactive-ion etching chamber, and the top cladding SiO2 layer was deposited through plasma-enhanced chemical vapor deposition. Finally, resistive Nichrome micro-heaters were deposited locally directly above each MR to offer the dynamic tuning capability. The strong optical confinement offered by the high index contrast between silicon and SiO2 makes it possible to fabricate micrometer-sized MRs with acceptable optical power loss caused by the small bending radii. The MRs were designed with a uniform diameter of 10 µm to support a wide free spectral range. All waveguides have a design dimension of 450 nm × 250 nm to allow operation exclusively in the fundamental mode at the 1.55 µm wavelength. A FSR of 18 nm with a spectral linewidth of 0.1 nm were observed for the fabricated MRs offering high wavelength selectivity. The device exhibits virtually no thermal crosstalk between adjacent channels, showing no output peak wavelength shift at 0.01 nm wavelength measurement precision by thermally tuning an adjacent MR with electric current as high as 7 mA, which is equivalent to about 2.5 nm in resonance wavelength tuning. The device showed a tuning delay time of about 1 ms. The overall bare chip size of the device is 20 mm × 4 mm. We demonstrated through this work a wavelength selective photonic switch device using low-cost SOI technology that is compact and easy to fabricate. It shows high potential for further development into high port-count photonic switch matrix.

In this thesis, we present and study the use of bent couplers in silicon-on-insulator (SOI) microring resonator (MRR) based filters. MRR based filters are attractive candidates in wavelength division-multiplexing (WDM) transceivers because of their compactness and low power consumptions. However, they suffer from drawbacks that include a limited free spectral range (FSR) which limit the number of channels that can be simultaneously multiplexed and/or demultiplexed. Our work investigates SOI single-ring MRR filters with bent couplers that have extended FSRs, enhanced filter performance (such as bandwidth, out-of-band rejection ratio, side-mode suppression, extinction ratio, and insertion loss) while maintaining compact footprints. Our aim is to make these filters attractive candidates to the current state-of-the-art WDM transceivers. We first demonstrated a 2.75 μm radius MRR filter that employs bent directional couplers in its coupling regions. This MRR filter was fabricated using a 248 nm photolithography process. Our filter has a 33.4 nm FSR and a 3-dB bandwidth of 25 GHz. Also, our MRR achieved an out-of-band-rejection ratio of 42 dB, an extinction ratio of 19 dB, and a drop-port insertion loss that is less than 1 dB. Lastly, our MRR filter has a tuning efficiency of 12 mW/FSR. Then, we theoretically and experimentally demonstrated an MRR filter with bent contra-directional couplers that exhibits an FSR-free response, at both the drop and through ports, while achieving a compact footprint. Also, using bent contra-directional couplers in the coupling regions of MRRs allows us to achieve larger side-mode suppressions than MRRs with straight CDCs. The fabricated MRR filter has a minimum suppression ratio of more than 15 dB, a 3dB-bandwidth of ~23 GHz, a through-port extinction ratio of ~18 dB, and a drop-port insertion loss of ~1 dB. High-speed data transmission through the MRR filter is demonstrated at data rates of 12.5 Gbps, 20 Gbps, and 28 Gbps.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate

Silicon photonics is a very promising technology for future low-cost high-bandwidth optical telecommunication applications down to the chip level. This is due to the high degree of integration, high optical bandwidth and large speed coupled with the development of a wide range of integrated optical functions. Silicon-based microring resonators are a key building block that can be used to realize many optical functions such as switching, multiplexing, demultiplaxing and detection of optical wave. The ability to tune the resonances of the microring resonators is highly desirable in many of their applications. In this work, the study and application of a thermally wavelength-tunable photonic switch based on silicon microring resonator is presented. Devices with 10µm diameter were systematically studied and used in the design. Its resonance wavelength was tuned by thermally induced refractive index change using a designed local micro-heater. While thermo-optic tuning has moderate speed compared with electro-optic and all-optic tuning, with silicon’s high thermo-optic coefficient, a much wider wavelength tunable range can be realized. The device design was verified and optimized by optical and thermal simulations. The fabrication and characterization of the device was also implemented. The microring resonator has a measured FSR of ~18 nm, FWHM in the range 0.1-0.2 nm and Q around 10,000. A wide tunable range (>6.4 nm) was achieved with the switch, which enables dense wavelength division multiplexing (DWDM) with a channel space of 0.2nm. The time response of the switch was tested on the order of 10 us with a low power consumption of ~11.9mW/nm. The measured results are in agreement with the simulations. Important applications using the tunable photonic switch were demonstrated in this work. 1×4 and 4×4 reconfigurable photonic switch were implemented by using multiple switches with a common bus waveguide. The results suggest the feasibility of on-chip DWDM for the development of large-scale integrated photonics. Using the tunable switch for output wavelength control, a fiber laser was demonstrated with Erbium-doped fiber amplifier as the gain media. For the first time, this approach integrated on-chip silicon photonic wavelength control.

Photonic sensing technologies offer unexceptionable features for taking high requirement measurement in a harsh environment. They inherit advantages such as fast speed and immunity from electromagnetic interference from optical communications. In addition, with the silicon-on-insulator (SOI) technologies, chip scale optical sensors are capable of providing high sensitivity with an ultra-compact form factor. The motivation is derived from the high demand for sensors in the new era of the Data Age and the great potential of fast response, highly sensitive and ultra-compact photonic sensor. Furthermore, rapid sensor development puts forward a new prospect for many areas such as medical and health measurement, defence technology, and the internet of things. With all the advantages that SOI-based chip scale optical sensors provide, there are still shortcomings can be improving to provided much more capable sensing abilities from many aspects. With that in mind, this thesis will focus on SOI-based optical microring resonator, one of the most popular SOI-based optical structure for sensing purpose; and solutions for two shortcomings of the common SOI-based optical sensor. One of the solutions that will be mentioned in this thesis is intended to solve the issues of limited measurement speed and low resolution that caused by the way of the data analysis in the common SOI-based optical sensing system. The second purposed solutions in this thesis focused on the connection schemes of the SOI-based optical sensor; Common connection schemes of SOI-based optical chip needs at least two optical ports for coupling the light into and out of the silicon photonics chip which limits the ability to perform measurements at remote locations that are hard to be reached. Chapter 4 and 5 of this thesis contains detailed explorations of these shortcomings and solutions. An integrated photonic sensor based on optoelectronic oscillator with an on-chip sensing probe that is capable of realising highly sensitive and high-resolution optical sensing is presented in this thesis as a solution for the first shortcoming. The key component is an integrated SOI-based microring resonator which is used to implement a microwave photonic bandpass filter (MPBF) to effectively suppress the side modes of the optoelectronic oscillator (OEO) by more than 30dB, thus generating a peak RF signal that maps the detected optical change into a resulting shift in the oscillating frequency. As an application example, the proposed optical sensor system is employed to detect small changes in temperature, and experimental results demonstrate a highly sensitive optical temperature sensor with an achieved sensitivity of 7.7 GHz/°C. Moreover, the proposed sensing system revealed a 0.02°C measurement resolution which is a tenfold improvement compared with the modest resolution of 0.23°C seen by the conventional MPBF system without the OEO loop, rendering it highly suitable for diverse high-resolution sensing applications. With the purpose of reducing the size of the SOI-based photonic sensor and to overcoming the second shortcoming, an ultra-compact, reflective optical sensor probe based on SOI microring resonator and Y-junction structure is also presented in this thesis. This structure is capable of simultaneously achieving high sensitivity and fine resolution optical sensing. The reflective configuration of the probe enables remote measurements at locations which are otherwise hard to be assessed by transmission based sensors. As an application example, the proposed sensor probe for temperature measurement is demonstrated. Experiment results show that the center wavelength shift of the sensor’s reflected spectrum offers a linear response to temperature change with a high sensitivity of 66 pm/°C.

The experimental work that is reported in the thesis explores some properties and possible uses of silicon microring resonators as integrated sources of non-classical states of light, based on the enhancement of non-linear effect of four-wave mixing (FWM).<br>The experimental work that is reported in the thesis explores some properties and possible uses of silicon microring resonators as integrated sources of non-classical states of light, based on the enhancement of non-linear effect of four-wave mixing (FWM).

The objective of this work is to develop essential building blocks for the lab-on-a-chip optical sensing systems with high performance. In this study, the silicon-on-insulator (SOI) platform is chosen because of its compatibility with the mature microelectronics industry for the great potential in terms of powerful data processing and massive production. Despite the impressing progress in optical sensors based on the silicon photonic technologies, two constant challenges are larger sensitivity and better selectivity. To address the first issue, we incorporate porous materials to the silicon photonics platform. Two porous materials are investigated: porous silicon and porous titania. The demonstrated travelling-wave resonators with the magnesiothermically reacted porous silicon cladding have shown significant enhancement in the sensitivity. The process is then further optimized by replacing the thermal oxide with a flowable oxide for the magnesiothermic reduction. A different approach of making porous silicon using porous anodized alumina membrane leads to better flexibility in controlling the pore size and porosity. Porous titania is successfully integrated with silicon nitride resonators. To improve the selectivity, an array of integrated optical sensors are coated with different polymers, such that each incoming gas analyte has its own signature in the collective response matrix. A multiplexed gas sensor with four polymers has been demonstrated. It also includes on chip references compensating for the adverse environmental effects. On chip spectral analysis is also very critical for lab-on-a-chip sensing systems. For that matter, based on an array of microdonut resonators, we demonstrate an 81 channel microspectrometer. The demonstrated spectrometer leads to a high spectral resolution of 0.6 nm, and a large operating bandwidth of ~ 50 nm.