Polarization modulated direct detection optical transmission systems

Abstract

A novel polarization modulated direct detection (PM-DD) system suitable both for binary and multilevel transmission is presented. At the transmitter the optical field is polarization modulated by a standard modulator. The receiver is based on the estimation of the Stokes parameters of the received optical field by means of a direct-detection optical front end and baseband electrical processing. The Poincare sphere rotation induced by the fiber is compensated by means of a purely electronic algorithm and the decision is performed in the Stokes space. The system performance is evaluated by an analytical model when the only relevant noise source is the receiver thermal noise and when erbium-doped optical amplifiers introduce amplified spontaneous emission (ASE) noise. The system is completely compatible with a direct-detection-based optical network, and it is possible to implement efficient multilevel modulation formats.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>