Adaptive PLL-free optical coherent receiver for joint polarization tracking and equalization in Phase-Shift-Keying for next-generation optical communication

Existing on-off-keying modulation in optical communication becomes inadequate to meet exponentially growing bandwidth demand. New receiver architectures and algorithms are being sought to confront this challenge. To achieve this goal, we propose innovative adaptive algorithms to simultaneously track optical polarizations and compensate any channel impairment without the need of any optical/electronic phase-locked-loop in Phase-Shift-Keying modulation for optical coherent receivers. These algorithms are demonstrated to be capable of coping with various impairments such as chromatic dispersion and polarization mode dispersion in optical channels to allow transmission of high speed data at 40 Gbps and beyond in even low-speed-grade long-haul fibers.