Cladding-pumped waveguide optical gyroscope

Patent metadata

Field	Value
Publication number	US-11022440-B2
Application number	US-201916562561-A
Country	US
Kind code	B2
Filing date	Sep 6, 2019
Priority date	Sep 22, 2016
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A waveguide optical gyroscope (WOG) is disclosed, which may include: an emitter; an integrated interferometer disposed on a silica planar lightwave circuit (PLC) and comprising a multilayer waveguide loop disposed in a first cladding material and interposed between layers of at least a second cladding material having an index of refraction lower than an index of refraction of the first cladding material; a pump source configured to pump the first cladding material with a signal that compensates for a propagation loss in the multilayer waveguide loop; and a micro-optic component configured to receive an output of the emitter and to guide the output into the integrated interferometer.

First claim

What is claimed is:

1. A waveguide optical gyroscope (WOG), comprising:
an emitter;
an integrated interferometer disposed on a silica planar lightwave circuit (PLC) and comprising a multilayer waveguide loop disposed in a first cladding material and interposed between layers of at least a second cladding material having an index of refraction lower than an index of refraction of the first cladding material;
a pump source configured to pump the first cladding material with a signal that compensates for a propagation loss in the multilayer waveguide loop;
a waveguide spot-size converter (i) further disposed on the same silica PLC and (ii) configured to reduce an insertion loss of a micro-optic component by an amount satisfying a criterion;
a symmetry between a clockwise propagation and a counter-clockwise propagation in the multilayer waveguide loop; and
the micro-optic component (i) further disposed on the same silica PLC, (ii) configured to receive an output of the emitter and to guide the output into the integrated interferometer, and (iii) comprising a micro-optic isolator and a plurality of phase modulators,
wherein the symmetry is maintained by a substantially uniform illumination by the pump source that minimizes longitudinal gain/loss variation along the multilayer waveguide loop.

2. The WOG of claim 1 , wherein the multilayer waveguide loop comprises a rare-earth (RE) doped silica.

3. The WOG of claim 1 , wherein the micro-optic isolator is configured to block backward propagating light from the multilayer waveguide loop towards the emitter.

4. The WOG of claim 1 , wherein the micro-optic component includes a micro-optic polarizer configured to control polarization of the guided output before transmission into the integrated interferometer.

5. The WOG of claim 1 , wherein the phase modulators comprise a plurality of X-cut lithium niobate phase modulators.

6. The WOG of claim 1 , wherein the integrated interferometer includes an active loop of multi-layer waveguides pumped by the pump source and another pump source, the pump sources facing opposite directions and being located at a center of the active loop.

7. The WOG of claim 1 , wherein the multilayer waveguide loop is doped with only Erbium or with Erbium and Ytterbium.

8. The WOG of claim 1 , wherein the pump signal is side-coupled and uniformly distributed in the first cladding material surrounding at least a portion of the multilayer waveguide loop.

9. The WOG of claim 1 , wherein the pump signal is sourced from pump lasers operated athermally.

10. The WOG of claim 1 , wherein the multilayer waveguide loop comprises multiple stacks to implement a Sagnac sensor having multiple waveguide layers and to multiply a length of delay to control a shot-noise limited bias stability.

11. The WOG of claim 10 , wherein the multiple stacks have no waveguide crossings, except at an inter-layer transition region, to reduce an impact of non-reciprocal perturbations.

12. The WOG of claim 1 , wherein a spacing of the multilayer waveguide loop is larger than an optical mode size to reduce power cross talk between neighboring waveguides.

13. The WOG of claim 1 , further comprising:
an optical filter having a passband that overlaps with a spectrally flat part of the output.

14. The WOG of claim 13 , wherein the micro-optic component includes a double-stage isolator and a collimating lens that is coated with the optical filter and that operates irrespective of a temperature.

15. The WOG of claim 1 , further comprising:
cladding pumping configured to achieve uniform population inversion along a plurality of doped waveguide cores.

16. The WOG of claim 1 , further comprising:
a trench configured to promote chaotic pump propagation throughout the multilayer waveguide loop.

17. The WOG of claim 16 , wherein the trench is further configured to promote even distribution of the signal throughout the multilayer waveguide loop.

18. The WOG of claim 1 , further comprising:
a local substitution in over-clad materials using a polymer to achieve athermal performance in an optical delay or a power splitting ratio in couplers.

19. The WOG of claim 1 , wherein the WOG operates over multiple fringes, the fringes being counted either in an open- or closed-loop mode.

20. The WOG of claim 1 , further comprising:
a mode-size expander on the multilayer waveguide loop and active alignment in flip-chip bonding of the pump source.

Assignees

• LGS Innovations LLC

Inventors

• Kang Inuk

Classifications

• G02F1/3519

  of Sagnac type, i.e. nonlinear optical loop mirror [NOLM] · CPC title

• H01S3/06795

  with superfluorescent emission, e.g. amplified spontaneous emission sources for fibre laser gyrometers (fibre laser gyrometers per se G01C19/72) · CPC title

• H01S3/10084

  Frequency control by seeding · CPC title

• H01S3/0637

  Integrated lateral waveguide, e.g. the active waveguide is integrated on a substrate made by Si on insulator technology (Si/SiO2) · CPC title

• H01S3/094007

  Cladding pumping, i.e. pump light propagating in a clad surrounding the active core · CPC title