适用400Gbit/s接收系统的铟磷基低暗电流高带宽倏逝波耦合光电探测器阵列

Low dark current and high bandwidth evanescent wave coupled PIN photodetector array for 400 Gbit/s receiving system

相较于面入射型和边入射型光电探测器,倏逝波耦合型光电探测器(evanescent coupling photodetector,ECPD)能够同时具备高带宽和高量子效率,因此在高速光通信领域有着广袤的应用前景.ECPD由稀释波导、单模脊波导和PIN光电二极管组成,通过倏逝波定向耦合提高光纤入射光到探测器吸收芯层的耦合效率.本文详细介绍了一种铟磷基ECPD阵列的结构设计、实验制备和测试结果.测试结果表明,制备的ECPD暗电流较低,在–3和0 V外加偏压下探测器暗电流低至215和1.23 pA.在有源区面积为5μm×20μm的情况下,器件仍能有较高响应度,为0.5 A/W(无增透膜).对探测器进行高频性能测试,探测器阵列的所有探测器带宽均超过25 GHz,总带宽400 GHz,可以集成任意光学器件.

Compared with surface and edge incident photodetectors,evanescent coupling photodetector(ECPD)has high bandwidth and high quantum efficiency,so it has a broad application prospect in the field of high-speed optical communication.The evanescent wave coupled photodetector is composed of a diluted waveguide,a single-mode ridge waveguide and a PIN photodiode.By directional evanescent wave coupling,the coupling efficiency of the incident light from the fiber to the absorption core of the photodetector is improved.In this paper,the structure design,experimental preparation and test results of an indium phosphorus based evanescent wave coupled photodetector array are introduced in detail.The test results show that the dark current of the evanescent wave coupled photodetector array is as low as 215 pA and 1.23 pA under–3 and 0 V bias,respectively.When the active area is 5μm×20μm,the device still has a high responsivity of 0.5 A/W(without antireflection film).The high frequency performance of the detector is tested.The bandwidth of each detector is more than 25 GHz,and the total bandwidth is more than 400 GHz.Any optical device can be integrated.The detector array can be applied to the WDM receiving system of 400 Gbit/s and coherent receiving system of 200 Gbit/s.