40-Gb/s QPSK with inserted pilot symbols using self-homodyne detection (フォトニックネットワーク) 40-Gb/s QPSK with inserted pilot symbols using self-homodyne detection

We proposed and experimentally demonstrated 40-Gb/s quadrature phase-shifted keying (QPSK) transmission systems with inserted pilot symbols, using a return-to-zero radio frequency (RZ-RF) driving signal in the transmitter and self-homodyne direct detection in the receiver. Different from other existing homodyne or conventional differential QPSK systems, the proposed QPSK modulation formats do not need any complicated pre-coder, post-processor or local oscillator. In the proposed QPSK systems, simultaneous detection of in-phase and quadature components is successfully achieved by using one Mach-Zehnder delay interferometer and following balanced detector, which significantly reduces the system complexity and implementation cost.