Optical modulator

Patent metadata

Field	Value
Publication number	US-2016357086-A1
Application number	US-201514732041-A
Country	US
Kind code	A1
Filing date	Jun 5, 2015
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

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,
first to fourth output ports for outputting light, and
a multimode interference optical splitter downstream of the input port for splitting the light received at the input port;
first and second Mach-Zehnder interferometers, each comprising:
first and second waveguides each optically coupled to a different one of the first to fourth output ports;
a Mach-Zehnder combiner comprising: first and second ingress ports optically coupled to the first and second waveguides, respectively; and a first egress port; and
a first phase shifter operationally coupled to the first waveguide, for modulating optical phase of light propagating in the first waveguide; and
a first optical combiner comprising:
first and second inlet ports each optically coupled to a different one of the first egress ports of the Mach-Zehnder combiners of the first and second Mach-Zehnder interferometers; and
a first outlet port for outputting the light modulated by the first phase shifters of the first and second Mach-Zehnder interferometers.

2 . The optical modulator of claim 1 , wherein the multimode interference optical splitter is optically coupled to the input port, and comprises first and second outlet ports,
wherein 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 of the multimode interference optical splitter, wherein the first Y-splitter comprises the first and second output ports of the optical splitter, and the second Y-splitter comprises the third and fourth output ports of the optical splitter.

3 . The optical modulator of claim 1 , wherein the multimode interference optical splitter is optically coupled to the input port, and comprises the first to fourth output ports.

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

5 . The optical modulator of claim 4 , wherein the multimode interference coupler further comprises a second outlet port for outputting residual light.

6 . The optical modulator of claim 5 , further comprising a photodetector optically coupled to the second outlet port, for detecting the residual light.

7 . The optical modulator of claim 3 , wherein each one of the Mach-Zehnder combiners of the first and second Mach-Zehnder interferometers comprises a multimode interference coupler comprising the first and second ingress ports, and the first egress port.

8 . The optical modulator of claim 7 , wherein each one of the multimode interference couplers of the Mach-Zehnder combiners of the first and second Mach-Zehnder interferometers further comprises a second egress port.

9 . The optical modulator of claim 1 , wherein the first and second Mach-Zehnder interferometers each further comprise a second phase shifter operationally coupled to the respective second waveguide, for modulating optical phase of light propagating in the respective second waveguide.

10 . The optical modulator of claim 1 , wherein the optical splitter further comprises fifth to eighth output ports for outputting light, the optical modulator further comprising:
third and fourth Mach-Zehnder interferometers, each comprising:
first and second waveguides each optically coupled to a different one of the fifth to eighth output ports;
a Mach-Zehnder combiner comprising: first and second ingress ports optically coupled to the first and second waveguides, respectively; and a first egress port; and
a phase shifter operationally coupled to the first waveguide, for modulating optical phase of light propagating in the first waveguide; and
a second optical combiner comprising: first and second inlet ports each optically coupled to a different one of the first egress ports of the Mach-Zehnder combiners of the third and fourth Mach-Zehnder interferometers; and a first outlet port for outputting the light modulated by the phase shifters of the third and fourth Mach-Zehnder interferometers.

11 . The optical modulator of claim 10 , wherein the multimode interference optical splitter is optically coupled to the input port, and comprises first and second outlet ports,
wherein 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 of the multimode interference optical splitter, and two egress ports; wherein the optical splitter further comprises third to sixth Y-splitters each comprising an ingress port optically coupled to a different one of the egress ports of the first and second Y-splitters, and two egress ports; wherein each one of the egress ports of the third to sixth Y-splitters is coupled to a different one of the first to eighth waveguides.

12 . The optical modulator of claim 10 , wherein the multimode interference optical splitter is optically coupled to the input port, and comprises the first to eighth output ports.

13 . The optical modulator of claim 12 , wherein each one of the Mach-Zehnder combiners of the first to fourth Mach-Zehnder interferometers comprises a multimode interference coupler comprising the first and second ingress ports thereof, and the first egress ports thereof.

14 . The optical modulator of claim 13 , wherein each one of the multimode interference couplers of the Mach-Zehnder combiners of the first to fourth Mach-Zehnder interferometers further comprises a second egress port for outputting residual light.

15 . The optical modulator of claim 14 , wherein each one of the first and second optical combiners comprises a multimode interference coupler comprising the first and second inlet ports thereof, and the first outlet ports thereof.

16 . The optical modulator of claim 13 , wherein each one of the first and second optical combiners comprises a multimode interference coupler comprising the first and second inlet ports thereof, and the first outlet ports thereof.

17 . The optical modulator of claim 12 , wherein the multimode interference optical splitter comprises a taper portion optically coupled to the input port, and an interference portion optically coupled to the first to eighth output ports.

18 . The optical modulator of claim 10 , wherein the multimode interference optical splitter is optically coupled to the input port, and comprises first to fourth outlet ports, the optical splitter further comprising first to fourth Mach-Zehnder multimode interference splitters each comprising an ingress port optically coupled to a different one of the first to fourth outlet ports of the multimode interference optical splitter,
wherein the first Mach-Zehnder multimode interference splitter comprises the first and second output ports of the optical splitter; wherein the second Mach-Zehnder multimode interference splitter comprises the third and fourth output ports of the optical splitter; wherein the third Mach-Zehnder multimode interference splitter comprises the fifth and sixth output ports of the optical splitter; and wherein the fourth Mach-Zehnder multimode interference splitter comprises the seventh and eighth output ports of the optical splitter.

19 . The optical modulator of claim 1 , wherein the optical splitter and the first optical combiner are disposed on different substrates.

20 . T

Assignees

• Jds Uniphase Corp

Inventors

• Jewart Charles M
• Lize Yannick

Classifications

• G02F1/2257 Primary

  the optical waveguides being made of semiconducting material · CPC title

• G02F2001/212

  Physics · mapped topic

• G02B6/28

  having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals · CPC title

• G02B6/2935

  Mach-Zehnder configuration, i.e. comprising separate splitting and combining means · CPC title

• G02B6/29344

  operating by modal interference or beating, i.e. of transverse modes, e.g. zero-gap directional coupler, MMI · CPC title