| With the transformation of telecom operators, a number of new integrated applications are beginning to operate, such as a variety of new IP services and awavelength-level operations (storage area network, SAN) faced to key customers, these operations can not be separated from WDM transmission bearer technology. In WDM system, photodetector is a major key device, which is the wavelength division multiplexing technology can be used in practical optical fiber communication systems and play to their power guarantee. For the current WDM systems, multiplexing hundreds of wavelengths, the transmission rate is up to tens of Tbit/s, high-performance photodetector requirements are also increasing.For another, the optical add-drop multiplexing (OADM) technology, in particular, reconfigurable optical add-drop multiplexing (ROADM) technology have received a lot of development in recent years, and the node has been actual used in the optical network of United States, Japan and other developed countries. ROADM equipment can be remotely configured to achieve a flexible adding and dropping of local optical wavelength, enabling the network acheive reconfiguration capabilities, so it has gradually become an important node in Optical Transport Network (OTN). But practical use of the ROADM nodes are combination of discrete functional components, at the same time, the price is more expensive, cost has become a major constraining factor in the development of ROADM technology.In this paper, a novel program is proposed for ultimate actualization high quantum efficiency, high-speed response, high-performance photodetector through a innovative strcture of dual-absorption resonant cavity-enhanced photodetectors; and the initial realization of the key features ROADM device integration is got by fabricating a photodetector array with wavelength selective function. The main research work is listed below:1. Basic structure and principle of Resonant Cavity Enhancement photodetectors and dual-absorption photodetectors are analyzed. Some significant factors of designing RCE photodetectors are summed up.2,A new dual-absorption Resonant Cavity Enhanced (RCE) photodetector that eases the bandwidth-efficiency limitation of conventional RCE photodetectors for long-wavelength application is proposed, in which, the dual-absorption layers are completely symmetric put inside a microcavity. In this case, high quantum efficiency is achieved by the function of dual-absorption layer and resonant cavity, high frequency respond is got by a thin single absorption. Theoretical analysis indicate that this design can achieve a quantum efficiency as high as 93% with a suitable reflectivity of top mirror, even 81% without a top DBR mirror for a thickness of 0.2um dual-absorption layer. And a 26GHz frequency bandwidth is achieved with mesa area for 30μm×30μm and 50-Ωload resistance. This design appears outstanding performance for allowing comparative simple photodetector to be applied in high-speed, high-sensitivity systems.3,A wavelength selective monolithically integrated photodetector array has been fabricated and characterized, which can be used for reconfigurable optical add-drop multiplexers.The integrated device consists of a GaAs/AlGaAs Fabry-Perot filter with InP-Ino.53Gao.47As-InP PIN photodetectors. In order to achieve much channel routing detection, the thickness of GaAs-based filter cavity is varied by wet etching, the filter is accomplished by overgrowth, and then InP-based structure heteroepitaxy growth is realized by low-temperature buffer layer approach. The device operates at a wavelength around 1550nm for four channels with 10nm interval. A spectral linewidth as narrow as 0.8nm, an external quantum efficiency of about 15%, and a 3dB bandwidth of 9GHz were obtained in the device. |
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