Characteristics of waveguide photodetectors at high-power optical input

High-power characteristics of waveguide photodetectors (PDs) with various absorbing layer thicknesses were analyzed. When large photocurrent was generated by high-power optical input, the saturation of radio frequency response was closely related with the optical absorption efficiency. The device with a single quantum well absorbing layer showed no saturation behavior until the device failure, while PDs with a thicker absorbing layer were saturated at photocurrent of a few milliamperes. It was also found that as optical confinement decreases, the maximum photocurrent the device can endure increases by more than three times.