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Studies On Integrated Demultiplexing Receivers For WDM Optical Networks

Posted on:2011-05-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:X F DuanFull Text:PDF
GTID:1118360308461948Subject:Physical Electronics
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The research works of this dissertation are supported by the National Basic Research Program of China (973 Project, No.2003CB314900), the National High Technology Research and Development Program of China (863 Project, No.2006AA03Z416 and No.2007AA03Z418), the 111 Project of China (No.B07005), and the Program of Key International Science and Technology Cooperation Projects (No.2006DFB11110).Recently, the increasing demand for bandwidth of telecommunication has greatly promoted the development of optical fiber communications. One of the promising technologies is wavelength-division multiplex (WDM) that has been developed rapidly in the long haul communications, and the all-optical network based on WDM just under intensively research. Wavelength-selective receiving has become the key technology of WDM applications. We have studied wavelength-selective photodetectors and got many achievements.In this dissertation, both theoretically and experimentally, long wavelength tunable photodetectors with high speed, high quantum efficiency and narrow spectral linewidth, monolithically integrated tunable wavelength-selective photodetector (WSPD) arrays, as well as reconfigurable multi-channel WDM drop module using a tunable WSPD array, are studied. The main contents and innovations are listed as follows.1. A novel monolithically integrated tunable photodetector has been completed successfully. Important progress has been made in the search for the heteroepitaxy of large mismatched materials. The difficult problems of manufacturing tunable electrodes have been solved. A 1550nm monolithically integrated tunable photodetector with GaAs DBRs and an InP p-i-n photodiode (GaAs-DBRs/InP-PD) was fabricated by employing a thin low-temperature buffer layer. A wavelength tuning range of 10.0 nm, an external quantum efficiency of about 20%, a spectral linewidth of 0.5 nm and a 3-dB bandwidth of 8.2 GHz have been obtained in this device.2. A novel GaAs-based multistep F-P filtering cavity (FPC) is proposed. The technological problems of the multistep FPC have been solved completely. This structure offers a new way for monolithically integrated WSPD photodetector arrays.3. It is the first time that a monolithically integrated WSPD photodetector array with a multistep cavity was fabricated. The methods of adhesive bonding using Benzocyclobutene (BCB) for photonic integrated circuits (PICs) are researched. On these bases, an integrated ROADM drop module for use in the long-wavelength is demonstrated using a tunable WSPD array. The photodetector array detects four wavelength channels, whose interval is about 10 nm, around 1550 nm. The maximal peak quantum efficiency is 20%. The tunable range reaches 10nm with a tuning power efficiency of 14.2nm/W, and the dropped wavelength shift dependence on tuning power is found to be linear. A spectral linewidth less than 0.5nm (FWHM) and a 3dB bandwidth of 10GHz were simultaneously obtained.4. The 1550nm InP/GaAs resonant cavity enhanced (RCE) photodetector with four-mirror and three-cavity (M4C3) has been realized first time. The high-quality GaAs/InP heteroepitaxy is realized by employing a thin low temperature buffer layer. By adopting M4C3 structure, high quantum efficiency, high response speed, and a narrow spectral response linewidth can be obtained simultaneously. A peak quantum efficiency of about 70%, a spectral linewidth of 0.5 nm and a 3-dB bandwidth of 8.0GHz have been obtained in this device.5. A novel dual-absorption RCE photodetector is proposed, which eases the bandwidth-efficiency limitation of conventional RCE photodetectors. Theoretical analyses indicate that a quantum efficiency as high as 93%, and a 26GHz frequency bandwidth can be achieved for 0.2um absorption layer thickness,30μm×30μm mesa area and 50-O load resistance.6. A novel RCE photodetector is proposed using subwavelength gratings (SWG) as the bottom mirrors. Simulation reveals that the total number of DBR's layers is less than conventional InGaAsP/InP DBR. Theoretical analyses indicate that a quantum efficiency as high as 90% can be achieved.
Keywords/Search Tags:monolithically integrated, photodetector, wavelength selective, tunable, reconfigurable optical add-drop multiplexer
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