DSP-Based Highly Linear Microwave Photonic Link

A coherent optical phase modulation link for the linear transport of analog radio frequency signals is presented. The technique utilizes the simultaneous and separate detection and digitization of optical in-phase and quadrature-phase signals for demodulation in the digital domain. Demodulation in the digital domain is found to allow significantly larger tolerance to the imperfect physical implementation of the phase demodulating receiver. We observe digitizer-limited performance achieving third order distortion improvement >50 dB for narrow instantaneous band widths (<10 MHz) and >40 dB for wide instantaneous bandwidths (<1 GHz).