High-performance GaNAsSb/GaAs 1.55-μm waveguide photodetector

We report on the small-signal high-frequency response of a GaNAsSb/GaAs pin waveguide photodetector at 1.55-μm wavelength. The GaNAsSb absorbing layer with 3.5% N and 18% Sb is sandwiched by GaAs-cladding layers. The device of an 8-μm ridge width and 15- μm ridge length has a dc responsivity of 0.44 A/W and an 11-GHz cutoff frequency at 5-m W optical illumination at a bias condition of -5 V. A higher cutoff frequency of 14.3-GHz is achieved on the smallest device of 4- μm ridge width and 17- μm ridge length with a responsivity of 0.2 A/W at a reverse bias condition of -1 V.