Automatic Tunable Chromatic Dispersion Compensation at 40 Gb/s in ASK and DPSK, NRZ, and CSRZ 263-km Transmission Experiments

Chromatic dispersion (CD) in single-mode optical fiber distorts pulses and is a big obstacle for the installation of long-haul dynamically routed transmission systems, especially at 40 Gb/s. Here the automatic residual CD compensation of a 263-km fiber link in the range -300 to -700 ps/nm is demonstrated for nonreturn-to-zero amplitude-shift keying (NRZ-ASK), carrier-suppressed return-to-zero (CSRZ)-ASK, NRZ differential phase-shift keying (DPSK), and CSRZ-DPSK modulation formats at 40 Gb/s. A thermally tunable dispersion compensator minimizes residual CD, which is measured by a synchronous arrival time detection scheme. The measured transmission penalty with online CD compensation is between /spl plusmn/1.2 dB for various link lengths and compensated CD values.