Design and Modeling of an Efficient High-Speed InGaAs/InP QW Waveguide-Photodetector

A physical model-based simulation is conducted to investigate the design of an efficient high-speed quantum-well waveguide-photodetector (WGPD). The WGPD structure is optimized in terms of photoabsorber thickness, i-region thickness, cladding doping and thickness. The carrier transit-time and device capacitance effect are reduced for a WGPD by employing a ≤ 50 nm thin-photoabsorber in a 0.66 μ m thick i-region design. A three-fold improvement in responsivity up to 0.82 A/W is obtained by using two graded-index layers. The accurately positioned TPA layer in a thick i-region can provide up to 50 μ m long WGPD. The optimized WGPD design can achieve 3-dB bandwidth over 80 and 50 GHz for 25 and 50 μ m long WGPD, respectively. The device satisfies the requirements of high-speed, low dark current, high responsivity, and integration capabilities, which is an essential prerequisite for high-performance detectors in future optical communication systems.