Study On Integrated Photonic Applications Based On The Spectral Characteristics Of Silicon Microring Resonators

The twenty-first Century is the era of information, the development of the Internet of things, cloud computing, big data centers and other emerging information technology industry is accompanied by the explosive growth of the transmission rate of information. Thus, optical communication has attracted more and more attention and been widely applied due to its advantages of wide bandwidth, low loss, low delay and strong resistance of the electromagnetic interference. In order to break through the bottleneck of the electrical interconnection, the high-speed optical interconnection between the cores or chips is needed. Thus, it has very important significance and value of application to research the silicon photonic devices and application with low cost and high integration density.Silicon based micro-ring resonator (MRR) has the advantages of simple structure, compact size and CMOS compatible production. The transmission of silicon MRR has a variety of optical characteristics which can be applied to realize a lot of photonic devices. Study on the silicon photonic applications based on tie spectral characteristics of MRR has extensive and important application prospects in silicon integrated photonics.This thesis makes the theoretical analysis and experimental demonstration of reconfigurable wavelength division multiplexing optical link (R-WDM-OL), bandwidth tunable filter (BTF) and ratio metric wavelength monitor (RMWM), which are all based on the transmission spectral characteristics of the fundamental element-silicon MRR. The main works are listed as follows:1. The four kinds of spectral characteristics of the MRR transmission, the filtering characteristic, the tunable characteristic, the coherent superposition characteristic and the edge filtering characteristic, are analyzed by the simulation using the transfer matrix method. These four characteristics have important application value and all the applications studied in this thesis are based on these four characteristics of the MRR transmission spectra.2. An 8-channel silicon reconfigurable WDM optical link (R-WDM-OL) is designed and fabricated by the CMOS-compatible process based on the filtering and thermally tunable characteristics of the transmission spectra of MRR. With low thermal tuning powers the channel allocation can be reconfigured with high accuracy and flexibility. The optical link consists of 1×8 thermally tunable micro-ring modulators and 1×8 thermally tunable micro-ring filters integrated with Ge-Si photo-detectors. The chip is opto-electronic packaged and tested. All the MRR can be tuned to cover one FSR and the thermal tuning efficiency is approximately 8mW/nm. We show eight-channel configurations with channel spacing of 100GHz and 50GHz and a configuration in which all eight channels cover an entire free spectral range of the ring with uniform channel spacing of 1.2nm. Each channel can receive high-quality signals with a data rate of up to 13.5Gbs-1; thus an aggregate data rate higher than 100Gbs-1 can be achieved.3. We demonstrate two kinds of silicon multiple MRRs based optical filters with tunable bandwidth and wavelength. One is based on the MRR-MZI structure with common bus waveguide and only one power combiner, the other one is based on the four MRRs cascaded structure. The principle that the bandwidth of the filter can be tuned applying the spectral filtering characteristics and the coherent superposition characteristics of the MRRs transmission is described, and the performance of the two schemes affected by the MRRs transmission spectral characteristics is analyzed in detail. The four MRRs based filter is fabricated and tested based on the analysis, the size of the filter is about 1.6mm×0.25mm. The test results show that the bandwidth of the filter can be tuned continuously from 0.6nm to 2.8nm (75GHz-350GHz) by thermally adjusting the wavelength spacing between the MRRs, the center wavelength of the filter can be thermally tuned to cover whole the FSR of 10nm, the thermal efficiency is about 0.03nm/mW. The insertion loss is from 1.26dB to 7.08dB according to different value of the tuned bandwidth.4. An ultrahigh-resolution ratio-metric wavelength monitor based on microring resonators (MRRs) is demonstrated on silicon applying the spectral edge filtering an tunable characteristics of the MRRs transmission. The theoretical wavelength resolution is related to the functional wavelength range and the quality (Q)-factor of the microring. We analyze the relationship and experimentally demonstrate that the functional range and the resolution can be adjusted by thermally tuning the resonance spacing of the MRRs. The resolution is also limited by the noise introduced in the measurements. An ultrahigh experimental resolution of 1.5 pm is obtained within a 0.72 nm functional range and an ultrahigh theoretical extreme resolution of ～0.4 pm can be expected considering of the intrinsic systems noise only. The causes of the difference between the experimental and theoretical resolution and the measures to reduce the difference are also discussed. Based on the MRRs based ultra-high resolution RMWM, we design and demonstrate the two-level wavelength monitor based on the etched diffraction gratings (EDG) and MRRs. Both wide functional range of 30nm and ultra-high resolution of 1.5pm can be achieved with the two-level system.