40Gbps PM-BPSK Modulator, Fujitsu FTM7980EDA, Lithium Niobate DP-BPSK Modulator This optical modulator is a Ti:LiNbO3 DP-BPSK Dual-Drive Mach-Zehnder modulator with modulation speed of up to 21.5Gbaud. This modulator comprises 3dB coupler, two BPSK modulators, polarization rotator followed by the polarization beam combiner and the built-in monitor PD chips for automatic bias control (ABC) for the compensation system of DC-drift and other phenomena. The FTM7980EDA modulator supports the advanced Dual Polarization-DPSK modulation scheme. In general, the DPSK format is particularly suitable for 40G ULH applications; in combination with coherent detection the 2*20G polarization multiplexed version is very attractive as an upgrade to existing 10G links to a 40G transmission rate without modification of the link.