Silicon photonic hybrid polarization demultiplexer

Patent metadata

Field	Value
Publication number	US-10330960-B2
Application number	US-201715663333-A
Country	US
Kind code	B2
Filing date	Jul 28, 2017
Priority date	Jul 8, 2014
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

An optical demultiplexer that includes at least one a hybrid phase shifter configured to receive a light signal over a fiber element, the light signal including polarized optical signals. Each phase shifter includes a thermo-optic phase shifter configured to phase shift the light signal, an electro-optic phase shifter configured to phase shift the light signal, and a coupler configured to maintain polarization of the polarized signal components. The optical demultiplexer also includes control circuitry configured to regulate the thermo-optic and electro-optic phase shifters.

First claim

We claim:

1. A polarization demultiplexer comprising:
at least one hybrid phase shifter configured to receive a light signal over a fiber element, the light signal including polarized optical signals, the at least one hybrid phase shifter each comprising:
a thermo-optic phase shifter configured to phase shift the polarized optical signals;
an electro optic-phase shifter configured to phase shift the polarized optical signals, wherein the electro optic-phase shifter and the thermo-optic phase shifter are connected in series; and
an input receiving a feedback error signal, the feedback error signal being based on an output of the demultiplexer;
feedback control circuitry regulating, based at least in part on a feedback error signal, the thermo-optic and electro-optic phase shifters as a pair to reduce an insertion loss of the hybrid phase shifter while maintaining a sufficient control bandwidth, the control circuitry further configured to send a control signal to the thermo-optic phase shifter and a dither signal to the electro-optic phase shifter.

2. The polarization demultiplexer of claim 1 , each hybrid phase shifter further comprising a coupler configured to maintain polarization of polarized optical signals of the light signal, the coupler and the hybrid phase shifter forming a mixing stage.

3. The polarization demultiplexer of claim 2 , further comprising:
a plurality of cascaded mixing stages.

4. The polarization demultiplexer of claim 1 , wherein the control signal and the dither signal having different amplitudes.

5. The polarization demultiplexer of claim 4 , wherein the dither signal has an amplitude that is less than an amplitude of the control signal.

6. The polarization demultiplexer of claim 1 , wherein polarized optical signals of the light signal are substantially orthogonal with respect to each other.

7. The polarization demultiplexer of claim 1 , wherein the electro-optical phase shifter includes one of a MOS capacitor, a PN junction, a P-I-N junction, or a Lithium Niobate (LiNbO3) phase modulator.

Assignees

• Cisco Tech Inc

Inventors

• Anderson Sean
• Webster Mark
• Shastri Kalpendu

Classifications

• G02F1/015 Primary

  based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction (G02F1/03 takes precedence) · CPC title

• G02F1/0123

  Circuits for the control or stabilisation of the bias voltage, e.g. automatic bias control [ABC] feedback loops · CPC title

• G02F1/225

  in an optical waveguide structure · CPC title

• G02F2203/50

  Phase-only modulation · CPC title

• G02F1/025

  in an optical waveguide structure (G02F1/017, {G02F1/2257} take precedence) · CPC title