Research On Micro-Ring Based Integrated Demulitiplexing Receiver Of DWDM Systems

Micro-ring resonator is compact wavelength-selective element that finds in many applications including add-drop filters,demultiplexers, dispersion compensators, and modulators.Its small size and functionality make it a key building block in densely-integrated planar light wave circuits.But there are not many reports on micro-ring photodetector. Microring photodetector has manymerits such as high speed, high quantum efficiency, small FWHM(full width at half maximum) and compact conformation.Compared with RCE-PD having vertical cavity, there is no need to fabricate DBR. The preparation of these devices are easier than any other waveguide integrated devices.The detailed theoretical analysis and parameter design of microring photodetector were carried out and the single ring resonator comprising multimode waveguide and RCE photodetector were experimentally fabricated with its performance tested, and the cascaded micro-ring resonator comprising single mode waveguide was explored experimentally. The main achievements in this paper are listed as follows. 1,The parameters of micro-ring resonator were calculated and stimulated in theory:the coupling coefficient between micro-ring waveguide and straight waveguide was analyzed using coupled mode theory and the transmission spectrum of micro-ring resonator was calculated using transmitted matrix method.The Verniar effect of cascaded micro-ring and the finite effect of transmission spectrum were analyzed.A novel cascaded micro-ring photodetector based on micro-ring resonator was proposed in theory. And their wavelength selection characteristics meets the ITU-T standard of DEMUX device used in DWDM. The transmission spectrum of these micro-ring resonator and their response properties were discussed, and results showed that the-3dB,-0.5dB and-20dB bandwidth were separately 0.85nm,0.3nm and 0.8nm. Demonstrating the photodetector characterized flat-top and steep-edge spectral response.2,The micro-ring and the micro-racetrack resonator were experimentally fabricated, the waveguide of which is multimode waveguide and the width of the waveguide is 3μm. The transmission spectrum of this two micro-ring resonator were measured.The RCE photodetector with vertical cavity was fabricated using GaAs/InP heteroepotaxial technique together with Dr. Ye Xian, while measuring its dark electrical and high frequency response properties.3,Fabrication of cascaded micro-ring photodetector was explored experimentally, and this photodetector meets the ITU-T standard of DEMUX device used in DWDM.It has respective absorption cavity and cavity resonator and the light vertically coupled to the absorption cavity from cavity resonator.The waveguide of micro-ring resonator is singlemode waveguide.The related techniques of this device is still in process.