Patent ID: 7483641
Filing Date: 2009-01-27
Classification: H04B

Abstract:
1. An optical hybrid, comprising: an input element for combining a data input optical signal and a local oscillator input optical signal and for splitting the combined input optical signals into first and second internal optical signals; an output element for recombining the internal optical signals and for splitting the combined internal optical signals into output optical signal components having a known phase relationship therebetween; and at least one phase delay element and at least one loss element connected between the input element and the output element, the phase delay element configured to apply a known phase delay to one of the internal optical signals and the loss element configured to apply a known attenuation to one of the internal optical signals; the known phase relationship being dependent, at least in part, on both the known phase delay and the known attenuation, wherein the phase delay element and the loss element co-operate to introduce said known phase relationship.