Use of waveguide grating couplers in an optical mux/demux system
View Patent ↗A group of waveguide grating couplers is disposed on a semiconductor substrate. The grating couplers are all within a spot illuminated on the substrate by a light from an optical fiber. The light propagating in the fiber is wavelength division multiplexed (WDM) and consists of several channels. Within the group of grating couplers, at least one grating coupler is designed to be tuned to each of the channels. The group of grating couplers demultiplexes the channels propagating in the fiber. A group of waveguide grating couplers can also be used to multiplex several channels of light into an optical fiber. Single mode and multimode fiber can be used to carry the multiplexed channels of light in an optical multiplexing and demultiplexing system.
1. An optical multiplexing/demultiplexing system comprising a plurality of waveguide grating couplers on a substrate and an optical port,
where the plurality of waveguide grating couplers are in the same optical path as light in the optical port, and are configured to couple light between a plurality of planar waveguides on the substrate and the optical port,
the optical port contains signals propagating on a plurality of wavelengths,
a first subset of the plurality of waveguide grating couplers is tuned to primarily couple light to/from a first subset of the plurality of wavelengths,
one of the plurality of waveguide grating couplers is tuned to primarily couple one wavelength of light from the optical port,
said optical multiplexing/demultiplexing system further comprising a plurality of photodetectors,
where the one wavelength of light coupled to one of the plurality of waveguide grating couplers is coupled to one of the plurality of photodetectors, and
said optical multiplexing/demultiplexing system further comprising a mirror disposed on top of the one of the plurality of photodetectors,
where the mirror substantially blocks incident light from impinging on top of the one photodetector.
2. An optical multiplexing/demultiplexing system comprising a plurality of waveguide grating couplers on a substrate and an optical port,
where the plurality of waveguide grating couplers are in the same optical path as light in the optical port, and are configured to couple light between a plurality of planar waveguides on the substrate and the optical port,
the optical port contains signals propagating on a plurality of wavelengths,
a first subset of the plurality of waveguide grating couplers is tuned to primarily couple light to/from a first subset of the plurality of wavelengths,
one of the plurality of waveguide grating couplers is tuned to primarily couple one wavelength of light from the optical port,
said optical multiplexing/demultiplexing system further comprising a plurality of photodetectors,
where the one wavelength of light coupled to one of the plurality of waveguide grating couplers is coupled to one of the plurality of photodetectors, and
wherein the one photodetector is positioned in the center of a waveguide grating coupler.
3. An optical multiplexing/demultiplexing system comprising a plurality of waveguide grating couplers on a substrate and an optical port,
where the plurality of waveguide grating couplers are in the same optical path as light in the optical port, and are configured to couple light between a plurality of planar waveguides on the substrate and the optical port,
the optical port contains signals propagating on a plurality of wavelengths,
a first subset of the plurality of waveguide grating couplers is tuned to primarily couple light to/from a first subset of the plurality of wavelengths,
one of the plurality of waveguide grating couplers is tuned to primarily couple one wavelength of light from the optical port,
said optical multiplexing/demultiplexing system further comprising a plurality of photodetectors,
where the one wavelength of light coupled to one of the plurality of waveguide grating couplers is coupled to one of the plurality of photodetectors, and
wherein the one photodetector is positioned in a ring surrounding a waveguide grating coupler.
4. An optical apparatus comprising a plurality of waveguide grating couplers on a substrate optically coupled to an optical fiber,
where first and second waveguide grating couplers of the plurality of waveguide grating couplers are optically coupled to respective first and second wavelengths of light propagating in the optical fiber,
wherein at least one of the plurality of waveguide grating couplers receives a wavelength of light coupled to it from the optical fiber,
said optical apparatus further comprising at least one photodetector on the substrate,
where the wavelength of light received by the at least one waveguide grating coupler is coupled to the photodetector, and
said optical apparatus further comprising a mirror disposed on top of the at least one photodetector,
where the mirror substantially blocks incident light from impinging on top of the photodetector.
5. An optical apparatus comprising a plurality of waveguide grating couplers on a substrate optically coupled to an optical fiber,
where first and second waveguide grating couplers of the plurality of waveguide grating couplers are optically coupled to respective first and second wavelengths of light propagating in the optical fiber,
wherein at least one of the plurality of waveguide grating couplers receives a wavelength of light coupled to it from the optical fiber, and
wherein the at least one photodetector is positioned in the center of the at least one waveguide grating coupler.
6. An optical apparatus comprising a plurality of waveguide grating couplers on a substrate optically coupled to an optical fiber,
where first and second waveguide grating couplers of the plurality of waveguide grating couplers are optically coupled to respective first and second wavelengths of light propagating in the optical fiber,
wherein at least one of the plurality of waveguide grating couplers receives a wavelength of light coupled to it from the optical fiber, and
wherein the at least one photodetector is positioned in a ring surrounding the at least one waveguide grating coupler.
7. An optical apparatus on a substrate comprising:
a first waveguide grating coupler,
a first photodetector optically coupled to the first grating coupler and
a mirror disposed on top of the first photodetector,
where the mirror blocks incident light from impinging on top of the first photodetector, wherein the mirror is placed on the same side of the substrate as a source of incident light.
8. The optical apparatus of claim 7 , and further comprising an optical fiber optically coupled to the first grating coupler.
9. The optical apparatus of claim 8 , and further comprising a plurality of wavelengths of light propagating in the optical fiber.
10. The optical apparatus of claim 8 , wherein the optical fiber is selected from a group consisting of: a single mode fiber, a multimode fiber and a polarization maintaining fiber.
11. An optical apparatus on a substrate comprising:
a first waveguide grating coupler,
a first photodetector optically coupled to the first grating coupler and
a mirror disposed on top of the first photodetector,
where the mirror blocks incident light from impinging on top of the first photodetector,
wherein the first photodetector is positioned in the center of the first grating coupler.
12. An optical apparatus on a substrate comprising:
a first waveguide grating coupler,
a first photodetector optically coupled to the first grating coupler and
a mirror disposed on top of the first photodetector,
where the mirror blocks incident light from impinging on top of the first photodetector,
wherein the first photodetector is positioned in a ring surrounding the first grating coupler.