Electronic and photonic processing in advanced photonic long-haul transmission

The advancements in electronic integrated-circuit technology and photonics in the last decade have allowed the design and demonstration of ultra-high-bit-rate transmission over advanced optical-fiber transmission lines employing inline optical amplification, as well as electronic compensation and equalization of linear and nonlinear distortion effects. Research and development into novel modulation techniques for achieving effective signal bandwidth and energy distribution per bit in order to extend the transmission reach are also attracting intensive interest. In this paper, we present: (i) A brief overview of optical-fiber communications employing advanced modulation and novel formats, especially the amplitude-and phase-shift keying with both discrete (DPSK, DQPSK, offset DQPSK) and continuous phase shifts (MSK, CPPSK…); (ii) Distortion and dispersion effects due to linear and nonlinear effects, and experimental demonstration of electronic and photonic compensation methodologies; (iii) Practical demonstration of the transmission of multiple channels at 40 Gb/s over several fiber spans of dispersion-managed optical fibers; and (iv) Demonstration of 40 Gb/ s over 10 Gb/s wavelength-multiplexed optically amplified long-haul transmission for capacity upgrading.