IP Library › Granted Patent US 12,322,926
Granted Patent B2
US 12,322,926 · App. 17/195,780 · Granted Jun 3, 2025

Tunable laser assembly

Inventors: Peter J. S. Heim (Washington, DC); John Hryniewicz (Columbia, MD); Jacob Mertz (Elkridge, MD); Jianfei Wang (Potomac, MD)
Assignee: Thorlabs Quantum Electronics, Inc.
H01S5/0683G01B9/02004G01B9/02091H01S3/1305H01S5/0064H01S5/02251H01S5/02253H01S5/02415H01S5/026H01S5/06835H01S5/142H01S5/18361
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Quick Facts
Patent No.
US 12,322,926
App. No.
17/195,780
Granted
Jun 3, 2025
Kind
B2
Abstract

A tunable laser assembly housed in a single enclosure and a method of control is described wherein the tunable laser, pump and semiconductor optical amplifier do not share a common optical axis but are all aligned to optical waveguides on an intervening planar lightwave circuit (PLC). Wavelength monitoring circuitry is included on the PLC to enable monitoring and control of the tunable laser center wavelength and optical bandwidth. The design of the PLC does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

Claims (48)

1. A tunable laser assembly comprising:

a tunable semiconductor laser emitting tunable laser radiation that sweeps over a range of wavelengths at a sweep rate;

a semiconductor optical amplifier (SOA);

at least one photodetector; and

a planar lightwave circuit (PLC);

wherein the tunable semiconductor laser, the SOA, and the at least one photodetector are aligned to optical waveguides on the PLC, and

wherein the PLC contains a wavelength monitoring circuit (WMC) that provides signal pulses to the at least one photodetector that enable control at least one of the absolute wavelength and width of the tuning range of said tunable laser radiation by observing the timing and number of the pulses as the tunable semiconductor laser sweeps across the wavelength range.

2. The tunable laser assembly of claim 1 , wherein said tunable semiconductor laser is a tunable MEMS-VCSEL.

3. The tunable laser assembly of claim 1 , wherein said semiconductor optical amplifier provides optical gain for substantially only one polarization.

4. The tunable laser assembly of claim 1 , wherein said at least one photodetector is comprised of a photodetector array.

5. The tunable laser assembly of claim 1 , wherein said PLC has a waveguide core comprised of one of silicon dioxide, silicon, or silicon nitride.

6. The tunable laser assembly of claim 1 , wherein said PLC has a waveguide index contrast greater than 1%.

7. The tunable laser assembly of claim 1 , wherein said PLC includes circuit elements configured to strip off unwanted radiation propagating in a polarization orthogonal to a fundamental polarization mode and prevent cross-coupling between the orthogonal and fundamental polarization modes that would cause an artifact in an optical coherence tomography (OCT) image.

8. The tunable laser assembly of claim 1 , wherein said tunable semiconductor laser, said SOA, said at least one photodetector, and said PLC are mounted on a common baseplate and a thermal electric cooler (TEC) attached to the common baseplate and controls the baseplate temperature.

9. The tunable laser assembly of claim 1 , wherein a lens is placed between at least one of said tunable semiconductor laser and said SOA, and at least one waveguide on said PLC.

10. The tunable laser assembly of claim 1 , wherein an optical isolator is placed between said tunable semiconductor laser and said PLC.

11. The tunable laser assembly of claim 10 , wherein said isolator is comprised of a quarter-wave polarization waveplate.

12. The tunable laser assembly of claim 1 , wherein said PLC incorporates a wavelength monitoring circuit comprised of wavelength filters designed to enable monitoring of the center wavelength and tuning bandwidth of said tunable laser assembly.

13. The laser of claim 12 , wherein said wavelength filters comprises at least one selected from a list of: a Bragg grating, a micro-ring resonator (MRR), and a Mach-Zehnder interferometer.

14. The tunable laser assembly of claim 13 , wherein a quarter-wave polarization waveplate is placed between said tunable semiconductor laser and said PLC.

15. The tunable laser assembly of claim 1 , wherein at least one of said tunable semiconductor laser and said at least one photodetector is attached on the top surface of said PLC.

16. The tunable laser assembly of claim 1 , wherein the optical signal from said tunable semiconductor laser is coupled to said PLC via an external turning mirror that enables vertical alignment of the optical signal by lateral adjustment of the external turning mirror.

17. The tunable laser assembly of claim 1 , wherein said semiconductor optical amplifier provides optical gain for substantially only one polarization.

18. The tunable laser assembly of claim 1 , wherein said at least one photodetector is comprised of a photodetector array.

19. The tunable laser assembly of claim 1 , wherein said PLC has a waveguide core comprised of one of silicon dioxide, silicon, or silicon nitride.

20. The tunable laser assembly of claim 1 , wherein said PLC has a waveguide index contrast greater than 1%.

21. The tunable laser assembly of claim 1 , wherein said PLC includes circuit elements configured to strip off unwanted radiation propagating in a polarization orthogonal to a fundamental polarization mode and prevent cross-coupling between the orthogonal and fundamental polarization modes that would cause an artifact in an optical coherence tomography (OCT) image.

22. The tunable laser assembly of claim 1 , wherein said PLC is comprised of a wavelength monitoring circuit to enable monitoring of the center wavelength and tuning bandwidth of said tunable laser assembly.

23. The tunable laser assembly of claim 1 , wherein at least one of said tunable semiconductor laser and said at least one photodetector is attached on the top surface of said PLC.

24. The tunable laser assembly of claim 1 , wherein the optical signal from said tunable semiconductor laser is coupled to said PLC via an external turning mirror that enables vertical alignment of the optical signal by lateral adjustment of the external turning mirror.

25. A tunable laser assembly comprising:

a tunable semiconductor laser emitting tunable laser radiation that sweeps over a range of wavelengths at a sweep rate;

a pump laser;

a semiconductor optical amplifier (SOA);

at least one photodetector; and

a planar lightwave circuit (PLC);

wherein the tunable semiconductor laser, the pump laser, the SOA, and the at least one photodetector are aligned to optical waveguides on the PLC; and

wherein the PLC contains a wavelength monitoring circuit (WMC) that provides signal pulses to the at least one photodetector that enable control at least one of of the absolute wavelength and width of the tuning range of said tunable laser radiation by observing the timing and number of the pulses as the tunable semiconductor laser sweeps across the wavelength range.

26. The tunable laser assembly of claim 25 , wherein said tunable semiconductor laser is an optically-pumped tunable MEMS-VCSEL.

27. The laser of claim 26 , wherein said WMC comprises at least one selected from a list of: a Bragg grating, a micro-ring resonator (MRR), and a Mach-Zehnder interferometer.

28. The tunable laser assembly of claim 25 , wherein said pump laser is a single-frequency laser having a side-mode suppression ratio of 30 dB or greater.

29. The tunable laser assembly of claim 25 , wherein said pump laser is one of a distributed feedback (DFB) laser, distributed Bragg reflector (DBR) laser, volume holographic (VHG) stabilized laser.

30. The tunable laser assembly of claim 25 , wherein said tunable semiconductor laser, said pump laser, said SOA, said at least one photodetector, and said PLC are mounted on a common baseplate and a thermal electric cooler (TEC) attached to the common baseplate and controls the baseplate temperature.

31. The tunable laser assembly of claim 25 , wherein said pump laser is comprised of an external cavity reflector circuit on said PLC that forms an external cavity laser in combination with a pump laser.

32. The tunable laser assembly of claim 25 , wherein said pump laser is hybrid or heterogeneously integrated on the PLC.

33. The tunable laser assembly of claim 25 , wherein a lens is placed between at least one of said tunable semiconductor laser, said pump laser, and said SOA, and at least one waveguide on said PLC.

34. The tunable laser assembly of claim 25 , wherein an optical isolator is placed between said pump laser and said PLC.

35. The tunable laser assembly of claim 25 , wherein said optical isolator is comprised of a quarter-wave polarization waveplate.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 12, 2021
From: HEIM, PETER J.S.; HRYNIEWICZ, JOHN; MERTZ, JACOB; WANG, JIANFEI
To: THORLABS QUANTUM ELECTRONICS, INC.
Reel/Frame 055579/0273 →
Continuity (3)
Provisional Application 62989007 · Mar 13, 2020
Provisional Application 62987102 · Mar 9, 2020
Related Publication 20210281046A1 · Sep 9, 2021
References Cited (52)
US 5850292A · Braun · 1998 [cited by applicant]
US 5982791A · Sorin · 1999 [cited by applicant]
US 6043883A · Leckel · 2000 [cited by applicant]
US 6362878B1 · Wang · 2002 [cited by applicant]
US 6486984B1 · Baney · 2002 [cited by applicant]
US 6498800B1 · Watterson · 2002 [cited by applicant]
US 6594022B1 · Watterson · 2003 [cited by applicant]
US 11835836B1 · Wu · 2023 [cited by examiner]
US 20030039275A1 · Pezeshki · 2003 [cited by examiner]
US 20040188794A1 · Gothoskar · 2004 [cited by examiner]
US 20040264981A1 · Zhang et al. · 2004 [cited by applicant]
US 20080037608A1 · Zhou et al. · 2008 [cited by applicant]
US 20110178413A1 · Schmitt · 2011 [cited by examiner]
US 20140125991A1 · Johnson · 2014 [cited by applicant]
US 20140176958A1 · Flanders · 2014 [cited by examiner]
US 20170026131A1 · Orcutt · 2017 [cited by examiner]
US 20170074640A1 · Cable et al. · 2017 [cited by applicant]
US 20170192171A1 · Shi · 2017 [cited by examiner]
US 20170268988A1 · Swanson · 2017 [cited by examiner]
US 20170299697A1 · Swanson · 2017 [cited by examiner]
US 20180249555A1 · Sugiyama · 2018 [cited by applicant]
US 20190052063A1 · Tolstikhin · 2019 [cited by examiner]
US 20190137687A1 · Daniel · 2019 [cited by applicant]
US 20190280798A1 · Rahn · 2019 [cited by examiner]
US 20200069225A1 · Vizbaras et al. · 2020 [cited by applicant]
US 20210281046A1 · Heim et al. · 2021 [cited by applicant]
CN 1862898A · 2006 [cited by applicant]
CN 207439428U · 2018 [cited by applicant]
CN 108474643A · 2018 [cited by applicant]
CN 108474992A · 2018 [cited by applicant]
EP 3879643A1 · 2021 [cited by applicant]
EP 3879644A1 · 2021 [cited by applicant]
J. Peatross and M. Ware, “Physics of Light and Optics,” p. 79-105, published Aug. 14, 2008. (Year: 2008). [cited by examiner]
Johnson et al., “Tunable 1060nm VCSEL co-packaged with pump and SOA for OCT and LiDAR”, Proc. SPIE 10867, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXIII, 1086706 (Feb. 22, 2019). … [cited by examiner]
Lobintsov et al., “Highly efficient semiconductor optical amplifier for the 820-860-nm spectral range”, Quantum Electron. 40 305 (2010). (Year: 2010). [cited by examiner]
Nasu, H. et al., “Wavelength Monitor Integrated Laser Modules for 25-GHz-Spacing Tunable Applications”, IEEE Journal of Selected Topics in Quantum Electronics, Jan./Feb. 2005, pp. 157-164, vol. 11, No. 1, IEEE. [cited by applicant]
Yu, Runxiang et al., “Rapid High-Precision In Situ Wavelength Calibration for Tunable Lasers Using an Athermal AWG and a PD Array”, IEEE Photonics Technology Letters, Jan. 1, 2012, pp. 70-72, vol. 24, No. 1, IEEE. [cited by applicant]
Keysight Technologies, “81980A, 81960A, 81940A, 81989A, 81949A, and 81950A Compact Tunable Laser Sources Data Sheet”, 5988-8518EN, Dec. 2017, pp. 1-13. [cited by applicant]
Kim, Ryun et al., “Highly Linear-Polarized External Cavity Lasers Hybrid Integrated on Planar Lightwave Circuit Platform”, IEEE Photonics Technology Letters, Feb. 15, 2006, pp. 580-582, vol. 18, No. 4, IEEE. [cited by applicant]
Fan, Youwen et al., “Optically Integrated InP-Si3N4 Hybrid Laser,” IEEE Photonics Journal, Dec. 1, 2016, pp. 1-12, vol. 8, No. 6, Article Sequence No. 1505111. [cited by applicant]
Komljenovic, T., “Heterogeneous Silicon Photonic Integrated Circuits”, J. Lightwave Technol., vol. 34, No. 1, 2016, pp. 20-35. [cited by applicant]
Huang, Duanni et al., “Sub-kHz linewidth Extended-DBR Lasers heterogeneously integrated on silicon”, 2019 Optical Fiber Communications Conference and Exhibition (OFC), pp. 1-3, IEEE. [cited by applicant]
Schwelb, Otto, “Transmission, Group Delay, and Dispersion in Single-Ring Optical Resonators and Add/Drop filters—A Tutorial Overview”, Journal of Lightwave Technology, May 2004, pp. 1380-1394, vol. 22, No. 5, IEEE. [cited by applicant]
Bogaerts, Wim et al., “Silicon microring resonators”, Laser & Photonics Reviews, 2012, vol. 6, No. 1, pp. 47-73, Wiley Online Library. [cited by applicant]
Johnson et al., “Tunable 1060 nm VCSEL co-packaged with pump and SOA for OCT and LiDAR”, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XXIII, Proc. of SPIE vol. 1086, 1086706, 2019. [cited by applicant]
Extended European Search Report with written opinion issued by the European Patent Office for corresponding European Patent Application No. EP 21 16 0867, dated Jul. 6, 2021. [cited by applicant]
Extended European Search Report with written opinion issued by the European Patent Office for corresponding European Patent Application No. EP 21 16 0865.8, dated Jul. 16, 2021. [cited by applicant]
First Office Action issued by the Chinese Patent Office for Patent Application No. 202110257222.1, dated May 29, 2024, with machine-generated English translation attached. [cited by applicant]
First Office Action issued by the Chinese Patent Office for Patent Application No. 202110258332.X , dated May 31, 2024, with machine-generated English translation attached. [cited by applicant]
Requisition by the Examiner issued by the Canadian Patent Office for Canadian Patent Application No. 3111302, dated Nov. 30, 2023. [cited by applicant]
Second Office Action issued by The China National Intellectual Property Administration for Chinese Patent Application No. 202110258332.X, dated Oct. 29, 2024, with English translation attached. [cited by applicant]
Communication pursuant to Article 94(3) EPC issued by the European Patent Office for European Patent Application No. 21160865.8, dated Apr. 17, 2025. [cited by applicant]