Laser device

Patent metadata

Field	Value
Publication number	US-10340657-B2
Application number	US-201715602432-A
Country	US
Kind code	B2
Filing date	May 23, 2017
Priority date	Feb 10, 2012
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A laser device includes a tunable laser having a laser cavity and a laser control module placed outside the laser cavity, the tunable laser being configured to generate laser light having a center frequency, the laser control module being configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module includes an interferometer having interferometer mirrors and a tunable interferometer length, and wherein the interferometer length is tunable by an actuator arranged between the interferometer mirrors and by thermal variation.

First claim

The invention claimed is:

1. A laser device, comprising
a tunable laser comprising a laser cavity and a laser control module placed outside the laser cavity,
wherein:
the tunable laser is configured to generate laser light having a center frequency,
the laser control module is configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, and
the laser control module comprises an interferometer comprising interferometer mirrors and a tunable interferometer length, wherein the interferometer length is tunable by an actuator arranged between the interferometer mirrors and by thermal variation.

2. The laser device of claim 1 , wherein the laser control module is encapsulated inside a hermetically sealed housing.

3. The laser device of claim 1 , wherein the laser is a single frequency laser.

4. The laser device of claim 1 , wherein the laser is selected from a fiber laser, a diode laser or a solid-state laser.

5. The laser device of claim 1 , wherein the interferometer is a Fabry-Perot interferometer.

6. The laser device of claim 1 , wherein the interferometer comprises solid silica.

7. The laser device of claim 1 , wherein the interferometer has an interferometer finesse of at least about 40.

8. The laser device of claim 1 , wherein the interferometer has a Free Spectral Range of at least about 25 GHz.

9. The laser device of claim 1 , wherein the interferometer length is tunable by means of piezo inducement.

10. The laser device of claim 9 , wherein the interferometer comprises serially connected photo detectors to provide that an anode of one photo detector is connected to a cathode of the other, and the control signal is taken from a common terminal of the serially connected photo detectors.

11. The laser device of claim 1 , wherein the laser has an optical axis and the interferometer is arranged with an angle to the optical axis, and wherein the interferometer length is tunable by means of changes in the angle of the interferometer with respect to the optical axis.

12. The laser device of claim 1 , wherein the laser device comprises a temperature sensor.

13. The laser device of claim 12 , wherein the temperature sensor is placed in direct contact with the interferometer.

14. The laser device of claim 1 , wherein the interferometer is a temperature dependent frequency discriminating element.

15. The laser device of claim 1 , wherein the laser device comprises a thermo-electric element located for thermally tuning the interferometer.

16. The laser device of claim 1 , wherein the interferometer is encapsulated inside a thermally insulated housing.

17. The laser device of claim 1 , wherein the device is configured to monitor the power of the portion of the laser light directed to the laser control module before entering the interferometer to generate a reference signal, and wherein the device is configured to generate the control signal by the difference between the reference signal and the power of the laser light transmitted through the interferometer.

18. The laser device of claim 1 , wherein the interferometer is a silica based Fabry-Perot interferometer and the power is detected using photo detectors.

19. The laser device of claim 1 , wherein the fiber laser center frequency is continuously tunable using thermal and piezo control for tuning the interferometer length.

20. The laser device of claim 1 , wherein the actuator is a thermal expansion actuator.

21. A laser device, comprising
a tunable laser comprising a laser cavity and a laser control module placed outside the laser cavity,
wherein:
the tunable laser is configured to generate laser light having a center frequency,
the laser control module is configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, and
the laser control module comprises an interferometer comprising interferometer mirrors and a tunable interferometer length, wherein the interferometer length is tunable by an actuator arranged to control the distance between the interferometer mirrors.

Assignees

• Nkt Photonics As

Inventors

• Pedersen Jens E
• Varming Poul
• Poulsen Christian V
• Fagerhøj Thomas O
• Gøth Bjarke
• Sørensen Henrik

Classifications

• H01S5/0654

  Single longitudinal mode emission · CPC title

• H01S3/2391

  emitting at different wavelengths · CPC title

• H01S5/0687 Primary

  Stabilising the frequency of the laser · CPC title

• H01S2301/02

  ASE (amplified spontaneous emission), noise; Reduction thereof · CPC title

• H01S5/141

  using a wavelength selective device, e.g. a grating or etalon (H01S5/146 takes precedence) · CPC title