Tunable laser source

Patent metadata

Field	Value
Publication number	US-9728933-B2
Application number	US-201615094591-A
Country	US
Kind code	B2
Filing date	Apr 8, 2016
Priority date	Sep 30, 2014
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A tunable transmission optical filter is optically coupled between a laser section and semiconductor optical amplifier (SOA) section of a tunable laser device. The optical filter may be tuned to provide a high transmission near the lasing peak while suppressing a significant portion of back-propagating amplified spontaneous emission (ASE) of the SOA section. Without the optical filter, the laser output spectrum may develop side lobes of higher intensity after the ASE is amplified and reflected in the forward direction by the laser gain and mirror sections. While lessening the side lobes, the optical filter simultaneously transmits the laser peak for amplification by the SOA section.

First claim

What is claimed is:

1. A method comprising:
tuning a lasing wavelength of a tunable laser section to a calibration wavelength within a tuning range of the tunable laser section,
the tunable laser section being included in a tunable laser device, and
the tunable laser device including a tunable transmission optical filter and a semiconductor optical amplifier section;

scanning, based on tuning the lasing wavelength of the tunable laser section to the calibration wavelength, a center wavelength of a passband of the tunable transmission optical filter;
determining, based on scanning the center wavelength, an output optical power of a laser source or a side mode suppression ratio of the laser source;
selecting a value of the center wavelength corresponding to the determined output optical power or the determined side mode suppression ratio; and
associating the value of the center wavelength with the calibration wavelength.

2. The method of claim 1 , further comprising:
tuning the lasing wavelength of the tunable laser section to another calibration wavelength in a grid of calibration wavelengths;
scanning another center wavelength of the passband of the tunable transmission optical filter based on tuning the lasing wavelength of the tunable laser section to the other calibration wavelength;
determining, based on scanning the other center wavelength, another output optical power of the laser source or another side mode suppression ratio of the laser source;
selecting another value of the other center wavelength corresponding to the determined other output optical power or the determined other side mode suppression ratio; and
associating the other value of the other center wavelength with the other calibration wavelength.

3. The method of claim 2 , further comprising:
interpolating, for an additional calibration wavelength, the value of the center wavelength and the other value of the other center wavelength to determine an additional value of an additional center wavelength,
the additional center wavelength being within the tuning range of the tunable laser section.

4. The method of claim 3 , where the additional calibration wavelength is not included in the grid of calibration wavelengths.

5. The method of claim 3 , further comprising:
associating the additional value of the additional center wavelength with the additional calibration wavelength based on interpolating to determine the additional value of the additional center wavelength.

6. The method of claim 1 , further comprising:
providing the tunable laser device,
where tuning the lasing wavelength of the tunable laser comprises:
tuning the lasing wavelength of the tunable laser based on providing the tunable laser device.

7. The method of claim 1 , further comprising:
energizing the tunable laser section after associating the value of the center wavelength with the calibration wavelength;
energizing the tunable laser section and tuning the lasing wavelength to a first working wavelength within the tuning range of the tunable laser section;
tuning, based on energizing the tunable laser section, the center wavelength of the passband of the tunable transmission optical filter to increase the side mode suppression ratio at the first working wavelength; and
energizing, based on tuning the center wavelength of the passband, a semiconductor optical amplifier section.

8. An apparatus comprising:
a semiconductor optical amplifier section;
a tunable transmission optical filter; and
a tunable laser section,
the tunable laser section being calibrated to associate a value of a center wavelength of a passband of the tunable transmission optical filter with a calibration wavelength within a tuning range of the tunable laser section, and
the value of the center wavelength being selected based on a maximum output optical power or a maximum side mode suppression ratio associated with a scan of the center wavelength of the passband of the tunable transmission optical filter performed based on tuning the tunable laser section to the calibration wavelength.

9. The apparatus of claim 8 , where the tunable laser section is calibrated to a grid of calibration wavelengths.

10. The apparatus of claim 8 , where
the tunable laser section is calibrated to a particular calibration wavelength between a first calibration wavelength to which the tunable laser section is calibrated and a second calibration wavelength to which the tunable laser section is calibrated, and
the tunable laser section is calibrated to the particular calibration wavelength based on an interpolation associated with the first calibration wavelength and the second calibration wavelength.

11. The apparatus of claim 8 , where the tunable laser section, the tunable transmission optical filter, and the semiconductor optical amplifier section are optically coupled in sequence.

12. The apparatus of claim 8 , where the tunable laser section is configured to be energized based on being calibrated.

13. The apparatus of claim 8 , where the semiconductor optical amplifier section is configured to be energized after tuning the center wavelength of the passband to increase a side mode suppression ratio after energizing the tunable laser section.

14. The apparatus of claim 8 , where the tunable transmission optical filter further comprises:
a stopband to attenuate light at a particular wavelength,
the particular wavelength being different from a lasing wavelength that the passband is calibrated to transmit.

15. A method comprising:
providing a tunable laser device,
the tunable laser device comprising a semiconductor optical amplifier section, a tunable transmission optical filter, and a tunable laser section, and
the tunable laser device being calibrated to associate a value of a center wavelength of a passband of the tunable transmission optical filter with a calibration wavelength within a tuning range of the tunable laser section;

energizing the tunable laser section and tuning a lasing wavelength to a working wavelength within the tuning range of the tunable laser section;
tuning, based on energizing the tunable laser section, the center wavelength of the passband of the tunable transmission optical filter to increase a side mode suppression ratio at the working wavelength; and
energizing, based on tuning the center wavelength of the passband, the semiconductor optical amplifier section.

16. The method of claim 15 , where
the tunable transmission optical filter is associated with an optical loss at the working wavelength and
energizing the semiconductor optical amplifier section comprises:
energizing the semiconductor optical amplifier section to a particular level of amplification,
the particular level of amplification compensating for the optical loss at the working wavelength.

17. The method of claim 15 , further comprising:
calibrating tunable laser device based on providing the tunable laser device.

18. The method of claim 17 , where calibrating the tunable laser device comprises:
tuning the lasing wavelength to the calibration wavelength;
scanning, based on tuning the lasing wavelength to the calibration wavelength, the center wavelength of the passband of the tunable transmission optical filter;
determining, based on tuning the lasing wavelength of the tunable laser section to the calibration wavelength, an output optical power of a laser source or another side mode suppression ratio of the laser source;
selecting the value of the center wavelength corresponding to a maximum output optic

Assignees

• Lumentum Operations Llc

Inventors

• Larson Michael C

Classifications

• H01S5/026

  Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06) · CPC title

• G02B6/29389

  Bandpass filtering, e.g. 1x1 device rejecting or passing certain wavelengths (G02B6/2938 takes precedence) · CPC title

• G02B6/29395

  configurable, e.g. tunable or reconfigurable (switching G02B6/35) · CPC title

• H01S5/0078 Primary

  for frequency filtering · CPC title

• H01S5/06256

  with DBR-structure · CPC title