Simultaneous photonic generation of two microwave signals with precisely-controllable phase difference using orthogonal polarization modes

Optical microwave or millimeter-wave generation using the beat note of two lightwaves is an attractive technique because of its advantages of frequency-tunable micro/millimeter-wave generation, high selectivity of the operation frequency, and high-speed phase switching of the generated signals owing to the photonics-based scheme. In this paper, we propose and demonstrate the simultaneous generation of two microwave signals with a precisely-controlled phase difference using the orthogonal polarization modes existing in a polarization maintaining fiber. High stability and controllability of the phase difference between the generated two microwave signals was experimentally confirmed.