High saturation photocurrent THz waveguide-type MUTC-photodiodes reaching mW output power within the WR3.4 band

In this paper, we report on waveguide-type modified uni-traveling-carrier photodiodes (MUTC-PDs) providing a record high output power level for non-resonant photodiodes in the WR3.4 band. Indium phosphide (InP) based waveguide-type 1.55 mu m MUTC-PDs have been fabricated and characterized thoroughly. Maximum output powers of -0.6 dBm and -2.7 dBm were achieved at 240 GHz and 280 GHz, respectively. This has been accomplished by an optimized layer structure and doping profile design that takes transient carrier dynamics into account. An energy-balance model has been developed to study and optimize carrier transport at high optical input intensities. The advantageous THz capabilities of the optimized MUTC layer structure are confirmed by experiments revealing a transit time limited cutoff frequency of 249 GHz and a saturation photocurrent beyond 20 mA in the WR3.4 band. The responsivity for a 16 mu m long waveguide-type THz MUTC-PD is found to be 0.25 A/W. In addition, bow-tie antenna integrated waveguide-type MUTC-PDs are fabricated and reported to operate up to 0.7 THz above a received power of -40 dBm. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this paper, we present waveguide-type modified uni-traveling-carrier photodiodes (MUTC-PDs) with record high output power levels in the WR3.4 band. Indium phosphide (InP) based 1.55 μm MUTC-PDs have been fabricated and characterized. An optimized layer structure and doping profile design taking into account transient carrier dynamics enable achieving maximum output powers of -0.6 dBm at 240 GHz and -2.7 dBm at 280 GHz. The developed energy-balance model studies and optimizes carrier transport at high optical input intensities. The optimized MUTC layer structure exhibits advantageous THz capabilities, with a transit time limited cutoff frequency of 249 GHz and a saturation photocurrent exceeding 20 mA in the WR3.4 band.