Patent ID: 8112005
Filing Date: 2012-02-07
Classification: H04B

Abstract:
1. An optical receiver apparatus for use in a Return-to-Zero (RZ) system, the optical receiver apparatus comprising a conventional receiver and an all-optical decision element (ODE) at the input of the conventional receiver, the ODE realized with nonlinear optical elements comprising first and second non-linear optical loop mirrors (NOLMs) arranged in cascade, wherein the first NOLM has a first coupler arranged to split an optical RZ input signal incident thereon substantially equally into first counter-propagating loop signals that recombine at the first coupler to form a reduced pulse-width optical RZ signal for coupling to an input of the second NOLM and the second NOLM has a second coupler arranged to split an optical RZ signal incident thereon into substantially unequal second counter-propagating loop signals that recombine at the second coupler to form an output optical signal for coupling to the conventional receiver.