Photonic Vector Signal Generation Based on OEO and Optical Coherent QPSK Modulation

A novel scheme for photonic vector signal generation based on a self-starting optoelectronic oscillator (OEO) and optical coherent quadrature phase-shift keying (QPSK) modulation is proposed and experimentally demonstrated. The optical output sidebands of the OEO are employed for optical heterodyne mixing, where one first-order sideband is modulated by QPSK baseband data using a dual-parallel Mach-Zehnder modulator, followed by coherent detection so as to directly generate frequency-doubled K-band vector signals. In the experiment, a 19.9 GHz QPSK modulated vector signal with a bit rate of 100 Mb/s is generated when the OEO operates at 9.95 GHz. The generated signal is back demodulated with error vector magnitude (EVM) less than 7%.