| Recently, the rapid progress of long-haul, large capacity, high-bit-rate WDM optical fiber communication systems has greatly met the desperate requirements for communication bandwidth; at the same time, optoelectronic devices used in WDM systems are confronted with strim situations. The integrated optoelectronic devices are investigated extensively due to their advantages of low cost, low power consumption, compactness, high reliability, easy packaging, and so on. Key breakthroughs in large scale optoelectronic integration are indispensible for the continuous and rapid development of WDM technology in the future.This dissertation investigates the integrated WDM demultiplexing receiving devices based on epitaxially grown Fabry-Perot cavity (EG-FPC), mainly including wavelength-selective tunable flat-top photodetectors with high speed, narrow spectral linewidth, and a tunable photodetector array for multiwavelength receiving applications. The main achievements of this dissertation are listed as follows.1. The theoretical model of EG-FPC is established by using Transfer Matrix Method (TMM). By using this model as theoretical guidance, a novel technique for the relocation of transmission characteristics of EG-FPC is proposed and demonstrated experimentally. Compared with the conventional way, this new technique presents much higher efficiency, and consequentially lower the fabrication cost of relative demultiplxing receiving devices. 2. A photodetector array for four channel wavelength receiving applications, which can be incorporated in ROADM, is fabricated by the introduction of stepped microstructure in EG-FPC. The four measured response peaks locate at1559nm,1553nm,1541nm and1536nm, respectively. The peak quantum efficiencies range from14.5%to16%. The linewidths of the response peaks are around0.8nm, and the3dB bandwidth comes to10.8GHz. Tuning range achieves8.5nm.3. The influence of GaAs substrate on the transmission perforemance of EG-FPC is investigated by using TMM. The transmission peak of EG-FPC will deteriorate by splitting up due to the F-P effect of GaAs substrate; periodic osilation of the peak transmittivity of EG-FPC are abserved along with the alteration of substrate thickness; the split of the transmission peak can be depressed by thinning the substrate down to a suitable thickness range. The transmission perforemance of EG-FPC is improved by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing, which matches well with the theoretical results.4. A Si-based tunable flat-top photodetector is designed by the introduction of a2-step microstructure into Si-based F-P cavity. The top DBR of the device are7pairs of GaAs/AlGaAs, while the bottom one consisting of3.5pairs of SiO2/Ta2O5. The effective cavity thickness is37.32μm. The calculated1dB,3dB,6dB linewidths and quantum efficiency are0.5nm,0.8nm,1.2nm and40%, respectively. The device can be tuned by thermal-optic effect.5. A monolithically integrated tunable dual-wavelength photodetector with flat-top response is designed by the introduction of a4-step microstructure into EG-FPC. The detectable wavelength range of this photodetector which is with the configuration of InP-based PIN absorption structure on GaAs-based EG-FPC, is doubled by the introduction of dual-wavelengh response. However, the quantum efficiencies of the device are sacrificed.6. A kind of InP/In0.53Ga0.47As multijunction PIN photodiode (MJ-PIN-PD) is proposed. We calculated the3dB bandwidth, quantum efficiency and bandwidth-efficiency product (BEP) of the device in detail. Corresponding to junction areas of40×40μm2,30×30μm2,20×20μm2and10×10μm2, maximum BEPs are achieved when setting junction numbers and absorption layer thickness to be1,2,2,3and1.28μm,1.16μm,0.84μm,0.54μm, respectively. A dual-absorption PIN-PD based on GaAs-DBR is fabricated successfully. The measured results verify the enhancement of quantum efficiency in MJ-PIN-PD along with the introduction of the DBR. |
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