Patent ID: 10801891

Abstract:
An optical apparatus includes a waveguide-based frequency-selective structure with one or more input ports and N1 output ports where N1 is 2 or more. If input signals in a pair of input signals are separated in frequency by an integer multiple of the structure's free spectral range, and one of the pair is routed onto one output port, the other in the pair is also routed onto that port. The apparatus also includes: N2 waveguides, where N2<=N1, each having an input port coupled to a corresponding one of the N1 output ports, and a waveguide output port; N3 frequency-selective elements where N3<=N2, each having an input port coupled to a corresponding one of the N2 waveguide output ports and an output surface from which optical emission occurs at an optical frequency-dependent angle; and an element receiving optical emission from the N3 output surfaces, detecting a corresponding intensity pattern.