Transmission of 108-Gb/s PDM 16ADPSK signal on 25-GHz grid using non-coherent receivers

We demonstrate the transmission of 108-Gb/s polarization-division-multiplexed (PDM) 16-ary amplitude- and differential phase-shift-keying (16ADPSK) signal by using a non-coherent receiver. We generate the 16ADPSK signal by using a differential 8-ary phase-shift-keying (D8PSK) modulator and a phase-distortion-free amplitude-shift-keying (ASK) modulator. On the other hand, the receiver is implemented by using a delay interferometer based on a 3×3 fiber coupler and the data-aided phase-noise estimation (DAPNE) algorithm. By using these transmitter and receiver, we achieve a nearly quantum-limited receiver sensitivity in the back-to-back condition. In addition, we examine the possibility of transmitting 108-Gb/s signals on a 25-GHz grid without using the coherent detection technology. The results show that we can secure a sufficient optical-signal-to-noise (OSNR) margin after the transmission of 80-km long dispersion managed link. The achieved spectral efficiency is 4.0 bit/s/Hz.