Abstract We have studied the optical matching layers (OMLs) and external quantum efficiency in the evanescent coupling photodiodes (ECPDs) integrating a diluted waveguide as a fibre-to-waveguide coupler, by using the semi-vectorial beam propagation method (BPM). The physical basis of OML has been identified, thereby a general designing rule of OML is developed in such a kind of photodiode. In addition, the external quantum efficiency and the polarization sensitivity versus the absorption and coupling length are analysed. With an optical matching layer, the absorption medium with a length of 30μm could absorb 90% of the incident light at 1.55μm wavelength, thus the total absorption increases more than 7 times over that of the photodiode without any optical matching layer.
Received: 27 March 2008
Revised: 10 September 2008
Accepted manuscript online:
Fund: Project supported by the National
High Technology Research and Development Program of China (Grant No
2006CB302802).
Cite this article:
Zhang Yun(张云), Zuo Yu-Hua(左玉华), Guo Jian-Chuan(郭剑川), Ding Wu-Chang(丁武昌), Cheng Bu-Wen(成步文), Yu Jin-Zhong(余金中), and Wang Qi-Ming(王启明) Optical matching layer structures in evanescent coupling photodiodes at a wavelength of 1.55μm: physics, design and simulation 2009 Chin. Phys. B 18 225
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