Optical Phase Shifter

Patent metadata

Field	Value
Publication number	US-2016334648-A1
Application number	US-201615013538-A
Country	US
Kind code	A1
Filing date	Feb 2, 2016
Priority date	May 15, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

An optical device includes first and second waveguide phase arms each having optically coupled parallel sections of waveguides, the parallel sections of each one of the waveguide phase arms being dissimilar to reduce crosstalk. The device further includes a tunable element for applying a phase shift to an optical signal traversing the first phase arm. The waveguides of the parallel sections may have dissimilar dimensions, e.g. may vary in width, thickness, or both. The waveguides adjacent the tunable element may be suspended and/or underetched to improve thermal isolation and accordingly reduce power consumption of the optical device.

First claim

1 . An optical device comprising:
first and second waveguide phase arms each having optically coupled parallel sections of waveguides, the parallel sections of each one of the first and second waveguide phase arms being dissimilar to lessen crosstalk; and a tunable element for applying a phase shift to an optical signal traversing the first waveguide phase arm.

2 . The optical device as claimed in claim 1 wherein each optically coupled parallel section of waveguides forms a single lightpath.

3 . The optical device as claimed in claim 2 wherein the waveguides of the parallel sections have dissimilar dimensions.

4 . The optical device as claimed in claim 2 wherein adjacent waveguides of the parallel sections vary in one or more of gap, width, and/or thickness.

5 . The optical device as claimed in claim 4 wherein the first and second waveguide phase arms comprise a plurality of tapered waveguides of different dimensions which are connected by loops, and the loops form transitions between the different dimensions.

6 . The optical device as claimed in claim 5 wherein there are N parallel sections and N−1 loops, with N being an odd integer greater than or equal to 3, such that input and output signals in each one of the first and second waveguide phase arms travel in a same direction.

7 . The optical device as claimed in claim 4 wherein the tunable element comprises a thermo-optic heater thermally coupled to the first waveguide phase arm.

8 . The optical device as claimed in claim 7 wherein the optical device is a silicon photonic device, and wherein the thermo-optic heater comprises a metallic layer.

9 . The optical device as claimed in claim 7 wherein the first waveguide phase arm is suspended for better thermal isolation thereof.

10 . The optical device as claimed in claim 8 wherein the optical device in the region of the thermo-optic heater is underetched to improve thermal isolation of the first waveguide phase arm adjacent the thermo-optic heater.

11 . The optical device as claimed in claim 4 further comprising a coupler configured as both an input power splitter for splitting an input optical signal between the first and second waveguide phase arms, and as an output power combiner for recombining optical signals from the first and second waveguide phase arms to produce an output optical signal.

12 . The optical device as claimed in claim 11 wherein the optical device is configured as a Michelson interferometer, and wherein the first and second waveguide phase arms are terminated with waveguide reflectors at ends of the first and second waveguide phase arms.

13 . The optical device as claimed in claim 12 wherein the one or more couplers comprise a 2×2 coupler selected from a group consisting of an adiabatic coupler, a multimode interference (MMI) coupler, and a directional coupler.

14 . The optical device as claimed in claim 12 wherein the waveguide reflectors comprise loop mirrors.

15 . The optical device as claimed in claim 14 wherein the loop mirror comprises a compact Y-branch and a bent waveguide.

16 . The optical device as claimed in claim 4 wherein the optical device is configured as a thermo-optic switch.

17 . The optical device as claimed in claim 16 further comprising one or more couplers configured as input power splitters for splitting an input optical signal between the first and second waveguide phase arms, or as output power combiners for recombining the optical signal from the first and second waveguide phase arms to produce an output optical signal.

18 . The optical device as claimed in claim 17 wherein the optical device is configured as a tunable Mach-Zehnder interferometer based optical switch.

19 . The optical device as claimed in claim 18 wherein the optical device is configured as a modulator.

20 . The optical device as claimed in claim 2 wherein the optical device is configured as a tunable Mach-Zehnder interferometer wherein at least adjacent waveguides of the parallel sections have varying widths.

Assignees

• Lu Zeqin
• Murray Kyle Jacob
• Chrostowski Lukas
• Huawei Tech Canada Co Ltd

Inventors

• Lu Zeqin
• Murray Kyle Jacob
• Chrostowski Lukas

Classifications

• G02F1/0102

  Constructional details, not otherwise provided for in this subclass · CPC title

• G02F1/0147 Primary

  based on thermo-optic effects (G02F1/132 takes precedence) · CPC title

• G02F2001/215

  Physics · mapped topic

• G02F1/2257

  the optical waveguides being made of semiconducting material · CPC title

• G02F1/011

  in optical waveguides, not otherwise provided for in this subclass · CPC title