Optical modulator

Patent metadata

Field	Value
Publication number	US-9851615-B2
Application number	US-201715483553-A
Country	US
Kind code	B2
Filing date	Apr 10, 2017
Priority date	Jun 5, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

An optical modulator is disclosed, in which a MMI couplers are used for input signal splitting for branching into individual Mach-Zehnder interferometers, as well as for branching and combining from individual Mach-Zehnder waveguides. MMI couplers, splitters, and combiners may be cascaded and combined with single-mode Y-splitters and combiners to provide modulators of various types, including dual polarization, quadrature phase Mach-Zehnder interferometer base optical modulators.

First claim

What is claimed is:

1. An optical modulator comprising:
an optical splitter comprising:
an input port for receiving light;
a multimode interference optical splitter downstream of the input port for splitting the light received at the input port; and
first to fourth output ports for outputting the split light; and

at least one Mach-Zehnder interferometer including a Mach-Zehnder combiner,
the Mach-Zehnder combiner including:
a plurality of ingress ports, each corresponding to a different one of the first to fourth output ports, and an egress port;
a multimode interference coupler between the plurality of ingress ports and the egress port; and
another non-ingress port.

2. The optical modulator of claim 1 , further comprising:
a first Mach-Zehnder interferometer and a second Mach-Zehnder interferometer,
each of the first Mach-Zehnder interferometer and the second Mach-Zehnder interferometer comprising a first Mach-Zehnder combiner and a second Mach-Zehnder combiner, respectively; and

an optical combiner comprising:
first and second inlet ports each optically coupled to the egress port of the first Mach-Zehnder combiner and the egress port of the second Mach-Zehnder combiner; and
a outlet port for outputting the light.

3. The optical modulator of claim 2 , wherein the optical combiner comprises a multimode interference coupler comprising the first and second inlet ports and the outlet port.

4. The optical modulator of claim 3 , wherein the multimode interference coupler comprises an additional outlet port for outputting residual light.

5. The optical modulator of claim 4 , further comprising:
a photodetector for detecting the residual light.

6. The optical modulator of claim 2 , wherein the optical splitter and the optical combiner are disposed on different substrates.

7. The optical modulator of claim 1 , wherein each Mach-Zehnder interferometer, of the at least one Mach-Zehnder interferometer, further includes:
first and second waveguides each optically coupled to a different one of the first to fourth output ports.

8. The optical modulator of claim 7 , wherein each Mach-Zehnder interferometer, of the at least one Mach-Zehnder interferometer, further includes:
a first phase shifter operationally coupled to the first waveguide, for modulating the split light propagating in the first waveguide; and
a second phase shifter operationally coupled to the second waveguide, for modulating the split light propagating in the second waveguide.

9. The optical modulator of claim 1 , wherein
the multimode interference optical splitter comprises first and second outlet ports, and
the optical splitter further comprises first and second Y-splitters each comprising an ingress port optically coupled to a different one of the first and second outlet ports.

10. The optical modulator of claim 9 , wherein
the first Y-splitter includes the first and second output ports of the optical splitter, and
the second Y-splitter includes the third and fourth output ports of the optical splitter.

11. The optical modulator of claim 1 , wherein
the optical splitter further comprises fifth to eighth output ports for outputting light, and
at least one Mach-Zehnder interferometer includes a first, second, third, and fourth Mach-Zehnder interferometer, each of the first, second, third, and fourth Mach-Zehnder interferometers including:
a Mach-Zehnder combiner,
first and second waveguides each optically coupled to a different one of the first to eighth output ports,
a first phase shifter operationally coupled to the first waveguide, for modulating the split light propagating in the first waveguide; and
a second phase shifter operationally coupled to the second waveguide, for modulating the split light propagating in the second waveguide.

12. An optical modulator comprising:
a multimode interference optical splitter comprising an input port for receiving light and first to M th output ports for outputting split light, wherein M is at least 2;
first and second additional splitters for receiving the split light, further splitting the split light, and outputting the further split light on first to N th output ports, wherein N is at least 4; and
first through (N/2) th Mach-Zehnder interferometers, each Mach-Zehnder interferometer, of the first through (N/2) th Mach-Zehnder interferometers, including:
a Mach-Zehnder combiner including:
a plurality of ingress ports, each corresponding to a different one of the first to N th output ports, and an egress port; and
a multimode interference coupler between the plurality of ingress ports and the egress port.

13. The optical modulator of claim 12 , wherein
each Mach-Zehnder interferometer, of the first through (N/2) th Mach-Zehnder interferometers, includes a first Mach-Zehnder combiner and a second Mach-Zehnder combiner, respectively, and
the optical modulator further includes:
an optical combiner comprising:
first and second inlet ports each optically coupled to the egress port of the first Mach-Zehnder combiner and the egress port of the second Mach-Zehnder combiner; and
a outlet port for outputting the light.

14. The optical modulator of claim 13 , wherein the optical combiner comprises a multimode interference coupler comprising the first and second inlet ports and the outlet port.

15. The optical modulator of claim 14 , wherein the multimode interference coupler comprises an additional outlet port for outputting residual light.

16. The optical modulator of claim 15 , further comprising:
a photodetector for detecting the residual light.

17. The optical modulator of claim 12 , wherein each Mach-Zehnder interferometer, of the first through (N/2) th Mach-Zehnder interferometers, includes:
first and second waveguides each optically coupled to a different one of the first to N th output ports.

18. The optical modulator of claim 17 , wherein each Mach-Zehnder interferometer, of the first through (N/2) th Mach-Zehnder interferometers, includes:
a first phase shifter operationally coupled to the first waveguide, for modulating the split light propagating in the first waveguide; and
a second phase shifter operationally coupled to the second waveguide, for modulating the split light propagating in the second waveguide.

19. The optical modulator of claim 12 , wherein the first and second additional splitters are first and second Y-splitters, respectively.

20. The optical modulator of claim 19 , wherein
the first Y-splitter includes first and second output ports, and
the second Y-splitter includes third and fourth output ports.

Assignees

• Lumentum Operations Llc

Inventors

• Jewart Charles M
• Lize Yannick
• Kissa Karl

Classifications

• G02B6/2813

  based on multimode interference effect, i.e. self-imaging · CPC title

• G02F2201/58

  Arrangements comprising a monitoring photodetector · CPC title

• G02B6/125

  Bends, branchings or intersections · CPC title

• G02F1/2257 Primary

  the optical waveguides being made of semiconducting material · CPC title

• G02F2001/212

  Physics · mapped topic