Applying implicit training to polarization-division-multiplexed coherent optical systems

Abstract

We report the use of implicit training-aided channel estimation (ITA-CE) for polarization-division-multiplexed (PDM) single-carrier coherent optical systems. With the concept of ITA-CE, where the training sequence (TS) is arithmetically added onto the information symbols rather than appearing in separate time slots, overhead-free transmission can be achieved with minor optical signal to noise ratio (OSNR) penalty. ITA-CE system enables simple digital pilot-tone based frequency-offset compensation, and inherits the benefits from typical training-aided channel acquisition and data recovery. Furthermore, we address the issue of selfinterference to channel estimation (CE) of ITA-CE system in thi..