Fabrication And Test Of High-Performance Photodetector

The wavelength selective Photodector used for wavelength-division multiplexing (WDM) technology requires high speed, high quantum effi-ciency, narrow spectral line width, tunable characteristics at long wave-length and flat-top and steep-edge. This high-performance photodetector comprised of a filter and a detector is one of the key devices in WDM system. In the thesis, the fabrication and test of high-performance photo-detector were studied. The main achievements are listed as follows:1. Participated in the fabrication of GaAs-DBRs/InP-PD photode-tector. A Fabry-Perot filter composed by GaAs/AlGaAs DBRs is inte-grated on the p-i-n photodetector. The fabrication procedure includes li-thography, masking, etching, lifting-off, passivating and metal electrode fabricating, etc. 2. The methods of testing the spectral response and high-speed re-sponse were studied and the GaAs-DBRs/InP-PD photodetector was tested of the two characteristics. The test results show that the device ob-tains a 1576.3nm peak wavelength, a max quantum efficiency of 34.5%, a max responsiveness of 0.44A/W, a spectral linewidth of 1.7 nm and a 3-dB bandwidth of 12.8GHz.3. A circuital control method achieving the flat-top and steep-edge response of photodetectors was studied. To realize the scheme, a structure was designed and simulated. It includes three wavelength selective pho-todetectors with different center wavelengths, three preamplifiers, two voltage comparators and a logic gates. OptiSystem is used to simulate to support this structure.4. The circuit aimed to realizing the circuital control method was de-signed and fabricated. Appropriate ICs were chosen according to the sim-ulation parameters and manual welded on the PCB.