US 8,478,091 B2Granted

Single-Stage 1×5 grating-assisted wavelength division multiplexer

AssigneeNational Central University

InventorsHung-Chih Lu, Jen-Inn Chyi

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Abstract

A single-stage 1×5 grating-assisted wavelength division multiplexer is provided. A grating-assisted asymmetric Mach-Zehnder interferometer, a plurality of grating-assisted cross-state directional couplers and a plurality of novel side-band eliminators are combined to form the multiplexer. Only general gratings are required, not Bragg grating, for 5-channel wavelength division multiplexing in a single stage. A nearly ideal square-like band-pass filtering passband is obtained. The present disclosure can be used as a core device in IC-to-IC optical interconnects for multiplexing and demultiplexing of an optical transceiver. The present disclosure has a small size and good performance.

Claims3

Dependent claims

A single-stage 1×5 grating-assisted wavelength division multiplexer, comprising

a grating-assisted asymmetric Mach-Zehnder interferometer, said grating-assisted asymmetric Mach-Zehnder interferometer comprising
a first 3 dB directional coupler, said first 3 dB directional coupler being connected with an end of a first input waveguide to receive a light from said first input waveguide to divide said light into two lights having even powers;
an asymmetric phase-shifting waveguide region, an end of said asymmetric phase-shifting waveguide region being connected with said first 3 dB directional coupler, said asymmetric phase-shifting waveguide region having a first phase-shifting waveguide and a second phase-shifting waveguide, a parallel area of said asymmetric phase-shifting waveguide region being obtained by a part of said first phase-shifting waveguide and a part of said second phase-shifting waveguide, said part of said first phase-shifting waveguide being parallel to said part of said second phase-shifting waveguide with a fixed interval maintained, a phase difference being obtained from said parallel area of said asymmetric phase-shifting waveguide region after said two lights having even powers being passed through said first phase-shifting waveguide and said second phase-shifting waveguide separately;
a first grating, said first grating being obtained on said parallel area of said first phase-shifting waveguide and said second phase-shifting waveguide;
and
a second 3 dB directional coupler, said second 3 dB directional coupler being connected with another end of said asymmetric phase-shifting waveguide region to receive said two lights having said phase difference from said asymmetric phase-shifting waveguide region, said two lights having said phase difference being interfered with each other to process wavelength division multiplexing to be coupled to a first output waveguide, a sixth output waveguide and a seventh output waveguide by different wavelengths separately;
a first grating-assisted cross-state directional coupler, said first grating-assisted cross-state directional coupler being connected with an end of said grating-assisted asymmetric Mach-Zehnder interferometer through said sixth output waveguide, said first grating-assisted cross-state directional coupler comprising
said sixth output waveguide, an end of said sixth output waveguide being connected with said first phase-shifting waveguide;
a fourth output waveguide, a part of an end of said fourth output waveguide being parallel to a part of another end of said sixth output waveguide with a fixed interval maintained;
a second grating, said second grating being obtained on said fourth output waveguide and said sixth output waveguide;
and
a second output waveguide, an end of said second output waveguide being connected with an end of said fourth output waveguide;
a second grating-assisted cross-state directional coupler, said second grating-assisted cross-state directional coupler being connected with another end of said grating-assisted asymmetric Mach-Zehnder interferometer through said seventh output waveguide, said second grating-assisted cross-state directional coupler comprising
said seventh output waveguide, an end of said seventh output waveguide being connected with an end of second phase-shifting waveguide;
a fifth output waveguide, a part of an end of said fifth output waveguide being parallel to a part of another end of said seventh output waveguide with a fixed interval maintained;
a third grating, said third grating being obtained on said fifth output waveguide and said seventh output waveguide;
and
a third output waveguide, an end of said third output waveguide being connected with an end of said fifth output waveguide;
a first side-band eliminator, an end of said first side-band eliminator being connected with another end of said grating-assisted asymmetric Mach-Zehnder interferometer through said first output waveguide, said first side-band eliminator comprising
said first output waveguide, an end of said first output waveguide being connected with another end of said first phase-shifting waveguide;
a connecting waveguide, a part of an end of said connecting waveguide being parallel to a part of another end of said first output waveguide with a fixed interval maintained;
and
a fourth grating, said fourth grating being obtained on said first output waveguide and said connecting waveguide;
a second side-band eliminator, an end of said second side-band eliminator being connected with another end of said first side-band eliminator through said connecting waveguide, said second side-band eliminator comprising said connecting waveguide;
an eighth output waveguide, a part of an end of said eighth output waveguide being parallel to a part of another end of said connecting waveguide with a fixed interval maintained;
and
a fifth grating, said fifth grating being obtained on said eighth output waveguide and said connecting waveguide;
a third side-band eliminator, an end of said third side-band eliminator being connected with another end of said first grating-assisted cross-state directional coupler through said second output waveguide, said third side-band eliminator comprising
said second output waveguide;
a ninth output waveguide, a part of an end of said ninth output waveguide being parallel to a part of another end of said second output waveguide with a fixed interval maintained;
and
a sixth grating, said sixth grating being obtained on said second output waveguide and said ninth output waveguide;
and
a fourth side-band eliminator, an end of said fourth side-band eliminator being connected with another end of said second grating-assisted cross-state directional coupler through said third output waveguide, said fourth side-band eliminator comprising
said third output waveguide;
a tenth output waveguide, a part of an end of said tenth output waveguide being parallel to a part of another end of said third output waveguide with a fixed interval maintained;
and
a seventh grating, said seventh grating being obtained on said third output waveguide and said tenth output waveguide.

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Abstract

A single-stage 1×5 grating-assisted wavelength division multiplexer, comprising

a grating-assisted asymmetric Mach-Zehnder interferometer, said grating-assisted asymmetric Mach-Zehnder interferometer comprising
a first 3 dB directional coupler, said first 3 dB directional coupler being connected with an end of a first input waveguide to receive a light from said first input waveguide to divide said light into two lights having even powers;
an asymmetric phase-shifting waveguide region, an end of said asymmetric phase-shifting waveguide region being connected with said first 3 dB directional coupler, said asymmetric phase-shifting waveguide region having a first phase-shifting waveguide and a second phase-shifting waveguide, a parallel area of said asymmetric phase-shifting waveguide region being obtained by a part of said first phase-shifting waveguide and a part of said second phase-shifting waveguide, said part of said first phase-shifting waveguide being parallel to said part of said second phase-shifting waveguide with a fixed interval maintained, a phase difference being obtained from said parallel area of said asymmetric phase-shifting waveguide region after said two lights having even powers being passed through said first phase-shifting waveguide and said second phase-shifting waveguide separately;
a first grating, said first grating being obtained on said parallel area of said first phase-shifting waveguide and said second phase-shifting waveguide;
and
a second 3 dB directional coupler, said second 3 dB directional coupler being connected with another end of said asymmetric phase-shifting waveguide region to receive said two lights having said phase difference from said asymmetric phase-shifting waveguide region, said two lights having said phase difference being interfered with each other to process wavelength division multiplexing to be coupled to a first output waveguide, a sixth output waveguide and a seventh output waveguide by different wavelengths separately;
a first grating-assisted cross-state directional coupler, said first grating-assisted cross-state directional coupler being connected with an end of said grating-assisted asymmetric Mach-Zehnder interferometer through said sixth output waveguide, said first grating-assisted cross-state directional coupler comprising
said sixth output waveguide, an end of said sixth output waveguide being connected with said first phase-shifting waveguide;
a fourth output waveguide, a part of an end of said fourth output waveguide being parallel to a part of another end of said sixth output waveguide with a fixed interval maintained;
a second grating, said second grating being obtained on said fourth output waveguide and said sixth output waveguide;
and
a second output waveguide, an end of said second output waveguide being connected with an end of said fourth output waveguide;
a second grating-assisted cross-state directional coupler, said second grating-assisted cross-state directional coupler being connected with another end of said grating-assisted asymmetric Mach-Zehnder interferometer through said seventh output waveguide, said second grating-assisted cross-state directional coupler comprising
said seventh output waveguide, an end of said seventh output waveguide being connected with an end of second phase-shifting waveguide;
a fifth output waveguide, a part of an end of said fifth output waveguide being parallel to a part of another end of said seventh output waveguide with a fixed interval maintained;
a third grating, said third grating being obtained on said fifth output waveguide and said seventh output waveguide;
and
a third output waveguide, an end of said third output waveguide being connected with an end of said fifth output waveguide;
a first side-band eliminator, an end of said first side-band eliminator being connected with another end of said grating-assisted asymmetric Mach-Zehnder interferometer through said first output waveguide, said first side-band eliminator comprising
said first output waveguide, an end of said first output waveguide being connected with another end of said first phase-shifting waveguide;
a connecting waveguide, a part of an end of said connecting waveguide being parallel to a part of another end of said first output waveguide with a fixed interval maintained;
and
a fourth grating, said fourth grating being obtained on said first output waveguide and said connecting waveguide;
a second side-band eliminator, an end of said second side-band eliminator being connected with another end of said first side-band eliminator through said connecting waveguide, said second side-band eliminator comprising said connecting waveguide;
an eighth output waveguide, a part of an end of said eighth output waveguide being parallel to a part of another end of said connecting waveguide with a fixed interval maintained;
and
a fifth grating, said fifth grating being obtained on said eighth output waveguide and said connecting waveguide;
a third side-band eliminator, an end of said third side-band eliminator being connected with another end of said first grating-assisted cross-state directional coupler through said second output waveguide, said third side-band eliminator comprising
said second output waveguide;
a ninth output waveguide, a part of an end of said ninth output waveguide being parallel to a part of another end of said second output waveguide with a fixed interval maintained;
and
a sixth grating, said sixth grating being obtained on said second output waveguide and said ninth output waveguide;
and
a fourth side-band eliminator, an end of said fourth side-band eliminator being connected with another end of said second grating-assisted cross-state directional coupler through said third output waveguide, said fourth side-band eliminator comprising
said third output waveguide;
a tenth output waveguide, a part of an end of said tenth output waveguide being parallel to a part of another end of said third output waveguide with a fixed interval maintained;
and
a seventh grating, said seventh grating being obtained on said third output waveguide and said tenth output waveguide.

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