Patent ID: 8275224
Filing Date: 2012-09-25
Classification: G02B,H04B,H04J

Abstract:
1. An apparatus, comprising an arrayed waveguide grating (AWG) that comprises: a substrate having a planar surface; a first optical star coupler being along said surface and having first and second optical inputs and a first spatial array of optical outputs; a second optical star coupler being along said surface and having a second spatial array of optical inputs and a third spatial array of optical outputs; and an array of waveguide arms, each waveguide arm connecting one optical output of the first spatial array to a corresponding optical input of the second spatial array, wherein the array of waveguide arms is configured to cause a first set of four optical outputs of the third spatial array to receive four different phase combinations of light received at the first and second optical inputs in response to the light received at the first and second optical inputs being of about the same wavelength, wherein the four different phase combinations are combinations of the light from the first and second optical input ports with relative phases of about 0, π/2 radians, π radians, and 3π/2 radians.