US 12,248,189 B2
Demultiplexer
Thomas Pierre Schrans, Temple City, CA (US); Andrea Trita, Pasadena, CA (US); and Adam Scofield, Los Angeles, CA (US)
Assigned to Rockley Photonics Limited, Altrincham (GB)
Appl. No. 17/793,914
Filed by ROCKLEY PHOTONICS LIMITED, Altrincham (GB)
PCT Filed Jan. 22, 2021, PCT No. PCT/EP2021/051505
§ 371(c)(1), (2) Date Jul. 19, 2022,
PCT Pub. No. WO2021/148637, PCT Pub. Date Jul. 29, 2021.
Claims priority of provisional application 62/964,557, filed on Jan. 22, 2020.
Prior Publication US 2023/0058741 A1, Feb. 23, 2023
Int. Cl. G02B 6/42 (2006.01); G02B 6/12 (2006.01); G02B 6/293 (2006.01); H04B 10/2581 (2013.01)
CPC G02B 6/4215 (2013.01) [G02B 6/12019 (2013.01); G02B 6/29344 (2013.01); G02B 6/29352 (2013.01); G02B 6/2938 (2013.01); H04B 10/2581 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A demultiplexer, for use in a wavelength division multiplexed system, the demultiplexer comprising:
an input waveguide, configured to receive a wavelength division multiplexed signal;
a wavelength demultiplexing element, configured to demultiplex the multiplexed signal received from the input waveguide into a plurality of multi-spatial-mode demultiplexed signal components respectively having a plurality of different wavelengths;
a multi-spatial-mode output waveguide, the multi-spatial-mode output waveguide being coupled to the demultiplexing element and configured to receive one of the multi-spatial-mode demultiplexed signal components; and
a splitter, coupled to the multi-spatial-mode output waveguide, and configured to split the received multi-spatial-mode demultiplexed signal component into two single-spatial-mode outputs and to provide each of the two single-spatial-mode outputs to a respective transfer waveguide, and
wherein the demultiplexer includes an output Mach-Zehnder interferometer connected to each of the respective transfer waveguides and operable as a wavelength filter, each output Mach-Zehnder interferometer of the output Mach-Zehnder interferometers has two arms of different path lengths and is configured to multiplex two wavelengths that are equal distance from a channel center of the output Mach-Zehnder interferometer so that the frequency response of the output Mach-Zehnder interferometer is a flat-top response, and
wherein the demultiplexer includes an input Mach-Zehnder interferometer connected between the input waveguide and the demultiplexing element, the input Mach-Zehnder interferometer having two arms of different path lengths, and the input Mach-Zehnder interferometer being operable as a wavelength filter.