Fabrication tolerant wavelength demultiplexer receiver

A method of operating a receiver, the method comprising:

• receiving, from an optical fiber coupled to an input, an optical signal comprising n wavelengths;
• splitting the optical signal based on a polarization of the optical signal into a first optical signal with a first polarization and a second optical signal with a second polarization;
• demultiplexing, by a first demultiplexer, the first optical signal into n first outputs for each of the n wavelengths;
• demultiplexing, by a second demultiplexer, the second optical signal into n second outputs for each of the n wavelengths;
• routing each of the n first outputs and the n second outputs to n shared photodetectors, wherein each photodetector of the n shared photodetectors receives a first output of the first n outputs and a second output of the n second outputs, wherein the first output and the second output comprise the same wavelength;
• combining one of the first n outputs with a first wavelength and one of the n second outputs with the first wavelength at a photodetector of the n shared photodetectors into a combined signal;
• and
• photodetecting the combined signal.