Polarization-based dual channel wavelength locker

Patent metadata

Field	Value
Publication number	US-9972964-B2
Application number	US-201615132944-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Apr 19, 2016
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

An optical device may include a laser emitter to generate a first laser beam and a second laser beam with orthogonal polarization states. The optical device may include first and second photodetectors to generate respective first currents based on optical powers of the first and second laser beams. The optical device may include a polarization-based beam splitter to combine the first and second laser beams. The optical device may include a wavelength filter to filter the first and second laser beams based on respective wavelengths of the first and second laser beams. The optical device may include a third photodetector and a fourth photodetector to generate respective second currents based on optical powers of the first and second laser beams after filtration. The wavelengths of the first and second laser beams may be controlled based on the first currents and the second currents.

First claim

What is claimed is:

1. An optical device, comprising:
a dual laser emitter to generate a first laser beam and a second laser beam,
the first laser beam and the second laser beam to be associated with orthogonal polarization states;

a first photodetector and a second photodetector to generate respective first currents based on optical powers of the first laser beam and the second laser beam,
the first currents to be used to control wavelengths at which the first laser beam and the second laser beam are to be generated;

a polarization-based beam splitter to combine the first laser beam and the second laser beam based on the orthogonal polarization states;
a wavelength filter to filter the first laser beam and the second laser beam based on respective wavelengths of the first laser beam and the second laser beam; and
a third photodetector and a fourth photodetector to generate respective second currents,
the third photodetector and the fourth photodetector to generate the respective second currents based on optical powers of the first laser beam and the second laser beam after the first laser beam and the second laser beam are filtered by the wavelength filter,
the wavelengths of the first laser beam and the second laser beam to be controlled based on the first currents and the second currents.

2. The optical device of claim 1 , where the second laser beam that is combined with the first laser beam is a first portion of the second laser beam; and
where the optical device further comprises:
a beam splitter to receive the second laser beam and split the second laser beam into the first portion and a second portion,
the second portion to be received by the second photodetector,
the second photodetector to generate the first current corresponding to the second laser beam based on an optical power of the second portion.

3. The optical device of claim 1 , where the wavelength filter comprises at least one of:
an interferometer,
a Michelson interferometer,
a Fabry-Perot interferometer, or
a Fabry-Perot etalon.

4. The optical device of claim 1 , further comprising:
a crystal wedge to impart a spatial separation or an angular separation between the first laser beam and the second laser beam before the first laser beam and the second laser beam are to be outputted by the optical device.

5. The optical device of claim 1 , further comprising:
a waveplate to cause the first laser beam or the second laser beam to be polarized to cause the first laser beam and the second laser beam to have the orthogonal polarization states.

6. The optical device of claim 5 , where the dual laser emitter comprises a first laser emitter and a second laser emitter,
the first laser emitter being a different laser emitter than the second laser emitter.

7. The optical device of claim 1 , further comprising:
an output component to output the first laser beam and the second laser beam with a spatial separation or an angular separation.

8. A method, comprising:
receiving or generating a first laser beam and a second laser beam at orthogonal polarization states;
determining respective reference values for respective first portions of the first laser beam and the second laser beam,
the reference values being determined based on respective optical powers of the first portions;

combining second portions of the first laser beam and the second laser beam to form a third laser beam;
wavelength filtering the third laser beam to form a filtered laser beam,
the filtered laser beam including filtered second portions of the first laser beam and the second laser beam, respectively;

determining respective transmission values of the first laser beam and the second laser beam based on respective optical powers of the filtered second portions; and
controlling wavelengths of the first laser beam and the second laser beam based on the reference values and the transmission values.

9. The method of claim 8 , where generating the first laser beam and the second laser beam at the orthogonal polarization states comprises:
generating the first laser beam and the second laser beam at a same polarization state; and
changing a polarization state of the first laser beam or the second laser beam to cause the first laser beam and the second laser beam to have the orthogonal polarization states.

10. The method of claim 8 , where wavelength filtering the third laser beam comprises:
transmitting the third laser beam through one of:
an interferometer,
a Michelson interferometer,
a Fabry-Perot interferometer, or
a Fabry-Perot etalon.

11. The method of claim 8 , where determining the respective transmission values comprises:
directing the second portion of the first laser beam to a first photodetector based on a polarization state of the first laser beam,
the first photodetector generating a current based on which the transmission value for the first laser beam is determined; and

directing the second portion of the second laser beam to a second photodetector based on a polarization state of the second laser beam,
the second photodetector generating a current based on which the transmission value for the second laser beam is determined.

12. The method of claim 8 , where one or more of the reference values are determined after the second portions of the first laser beam and the second laser beam are combined to form the third laser beam.

13. The method of claim 8 , where determining the reference values comprises:
splitting the first laser beam, before the first laser beam and the second laser beam are combined, to cause the first portion of the first laser beam to be transmitted to a photodetector,
the photodetector generating a current based on the optical power of the first portion of the first laser beam,
the reference value being determined based on the current.

14. The method of claim 8 , where controlling the wavelengths comprises:
controlling the wavelength of the first laser beam based on a ratio of the reference value for the first laser beam to the transmission value for the first laser beam; and
controlling the wavelength of the second laser beam based on a ratio of the reference value for the second laser beam to the transmission value for the second laser beam.

15. The method of claim 8 , further comprising:
outputting spatially or angularly separated portions of the first laser beam and the second laser beam.

16. An optical device, comprising:
a dual laser emitter to generate a first laser beam and a second laser beam;
first and second photodetectors to generate respective reference values based on respective optical powers of the first laser beam and the second laser beam,
the first photodetector to generate the reference value for a first portion of the first laser beam,
the second photodetector to generate the reference value for a first portion of the second laser beam;

a polarization-based beam splitter to combine the first laser beam and the second laser beam into a combined laser beam based on the first laser beam and the second laser beam having different polarization states;
a wavelength filter to filter at least a portion of the combined laser beam based on wavelengths of the first laser beam and the second laser beam to form a filtered laser beam; and
third and fourth photodetectors to generate transmission values based on respective optical powers of respective second portions of the first laser beam and the second laser beam after the filtered laser beam is formed,
the third photodetector to generate the transmission value for the second portion of

Assignees

• Lumentum Operations Llc

Inventors

• Xiong Wei
• Larson Michael C
• Li Zhaoming

Classifications

• G02B27/283

  used for beam splitting or combining · CPC title

• G02F2001/215

  Physics · mapped topic

• H01S3/0064

  Anti-reflection devices, e.g. optical isolaters (absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955) · CPC title

• G02F2001/213

  Physics · mapped topic

• H01S3/0085

  Modulating the output, i.e. the laser beam is modulated outside the laser cavity · CPC title