Scalable silicon photonic multiplexers and demultiplexers

A method for multiplexing optical signals, wherein the method comprises:

• receiving the optical signals on optical waveguides;
• optically coupling the optical signals to coupled-waveguide grating devices using multiple add/drop filters that are optically coupled to the coupled-waveguide grating devices, wherein a given add/drop filter has a filter bandwidth corresponding to a given optical channel, thereby providing fine optical filtering;
• and
• optically coupling the optical signals from the coupled-waveguide grating devices to a bus optical waveguide, wherein a given coupled-waveguide grating device has a band-pass filter characteristic that encompasses multiple optical channels, thereby providing coarse optical filtering;
• and wherein the band-pass filter characteristic of the given coupled-waveguide grating device is approximately equal to or less than a free spectral range (FSR) of the given add/drop filter.

An optical modulator, comprising:

• a bus optical waveguide;
• an optical source configured to provide an optical signal;
• multiple coupled-waveguide grating devices configured to optically couple to the bus optical waveguide and the optical source, wherein a given coupled-waveguide grating device has a band-pass filter characteristic that encompasses multiple optical channels, thereby providing coarse optical filtering;
• and
• multiple ring-resonator modulators configured to optically couple to the coupled-waveguide grating devices, wherein a given ring-resonator modulator has a modulation characteristic corresponding to a bandwidth of a given optical channel, thereby providing fine optical modulation of the optical signal in the given coupled-waveguide grating device, and wherein the band-pass filter characteristic of the given coupled-waveguide grating device is approximately equal to or less than a free spectral range (FSR) of the given ring-resonator modulator.