Realising Polarisation Modulation Using a DP-BPSK Modulator

This work introduces two microwave photonic configurations that emulate the functional behavior of a polarization modulator operated in both push-pull and single-arm drive modes. The proposed schemes are implemented using a commercially available dual-polarization binary phase-shift keying (DP-BPSK) modulator, where RF circuitry is attached to the modulator’s input ports. A voltage variation of 2Vπ applied to the RF port—where Vπ denotes the half-wave voltage—drives the output optical polarization to trace a great circle trajectory on the Poincaré sphere. Furthermore, by placing a rotatable linear polarizer at the output of the single-arm equivalent polarization modulator, the system is capable of producing not only polarization modulation but also phase and intensity modulation. Experimental demonstrations confirm the feasibility of realizing polarization, phase, and intensity modulation using the DP-BPSK modulator. In addition, two polarization-modulator-based microwave photonic signal processing units are experimentally configured to validate the high frequency operation of the proposed equivalent modulators in both push-pull and single-arm drive arrangements.