Third-Harmonic Power Extraction From InP Gunn Devices up to 455 GHz

InP Gunn devices with graded doping profiles were evaluated for third-harmonic power extraction above 400 GHz in a configuration with a tapered output waveguide that cuts off both fundamental and second-harmonic frequencies of the oscillator. The best devices generated RF output powers of 283 muW at 412 GHz and 203 muW at 429 GHz. The highest third-harmonic frequency observed was 455 GHz at an output power of 23 muW .