IP Library › Granted Patent US 12,646,902
Granted Patent B1
US 12,646,902 · App. 18/098,628 · Granted Jun 2, 2026

Laser reference frequency source stabilized by optical self-injection locking

Inventors: Jiang Li (Alhambra, CA); Kerry Vahala (Pasadena, CA)
Assignee: HQPHOTONICS INC.
H01S3/1312H01S3/06791H01S3/094003H01S3/094096H01S3/0941H01S3/302
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Quick Facts
Patent No.
US 12,646,902
App. No.
18/098,628
Granted
Jun 2, 2026
Kind
B1
Abstract

A first pump laser source produces a first pump optical signal at a first pump optical frequency v 1P and launches it into a ring optical resonator to propagate in a forward direction around the ring optical resonator. A backscattered portion of the first pump optical signal propagates back to the first pump laser source and injection-locks it so that the first pump optical frequency v 1P is locked to a first resonant mode optical frequency of the ring optical resonator. A second laser source producing a second pump optical signal at a second optical frequency v 2P and can be similarly self-injection-locked to a second resonant mode optical frequency of the ring optical resonator different from the first resonant mode optical frequency.

Claims (38)

1 . An apparatus comprising:

(a) a ring optical resonator;

(b) a first pump laser source arranged so as to (i) produce a first pump optical signal at a first pump optical frequency v 1P , and (ii) launch at least a portion of the first pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the first pump laser source being arranged so that a portion of the first pump optical signal backscattered by the ring optical resonator propagates back to the first pump laser source and injection-locks the first pump laser source so that the first pump optical frequency v 1P is locked to a first resonant mode optical frequency of the ring optical resonator;

(c) a second pump laser source arranged so as to (i) produce a second pump optical signal at a second pump optical frequency v 2P , and (ii) launch at least a portion of the second pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the second pump laser source being arranged so that a portion of the second pump optical signal backscattered by the ring optical resonator propagates back to the second pump laser source and injection-locks the second pump laser source so that the second pump optical frequency v 2P is locked to a second resonant mode optical frequency of the ring optical resonator different from the first resonant mode optical frequency; and

(d) an optical detector arranged so as (i) to receive at least a portion of the first pump optical signal and at least a portion of the second pump optical signal, and (ii) to generate therefrom an electrical output signal at a difference frequency v DIFF =|v 2P −v 1P | that is less than 200 GHz.

2 . The apparatus of claim 1 wherein the difference frequency v DIFF =|v 2 −v 1 | is greater than 0.3 GHz.

3 . The apparatus of claim 1 wherein (i) the difference frequency v DIFF =|v 2 −v 1 | exhibits fluctuations over a 0.1 second timescale only within a bandwidth less than 100 Hz, or (ii) the output electrical signal exhibits phase noise less than −80 dBc/Hz at 10 kHz offset frequency.

4 . The apparatus of claim 1 wherein (i) the difference frequency v DIFF =|v 2 −v 1 | exhibits fluctuations over a 0.1 second timescale only within a bandwidth less than 1 Hz, or (ii) the output electrical signal exhibits phase noise less than −100 dBc/Hz at 10 KHz offset frequency.

5 . The apparatus of claim 1 wherein one or both of the first or second pump lasers sources are semiconductor diode lasers.

6 . The apparatus of claim 1 wherein one or both of the first or second pump optical frequencies v 1P and v 2P are greater than 75 THz or less than 750 THz.

7 . The apparatus of claim 1 wherein the ring optical resonator comprises a ring waveguide optical resonator on a substrate.

8 . The apparatus of claim 1 wherein the ring optical resonator comprises a disk optical resonator.

9 . The apparatus of claim 1 wherein the ring optical resonator comprises a fiber-loop optical resonator.

10 . The apparatus of claim 1 wherein the optical resonator exhibits a Q-factor greater than 10 6 .

11 . An apparatus comprising:

(a) a ring optical resonator;

(b) a first pump laser source arranged so as to (i) produce a first pump optical signal at a first pump optical frequency v 1P , and (ii) launch at least a portion of the first pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the first pump laser source being arranged so that a portion of the first pump optical signal backscattered by the ring optical resonator propagates back to the first pump laser source and injection-locks the first pump laser source so that the first pump optical frequency v 1P is locked to a first resonant mode optical frequency of the ring optical resonator;

(c) a second pump laser source arranged so as to (i) produce a second pump optical signal at a second pump optical frequency v 2P , and (ii) launch at least a portion of the second pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the second pump laser source being arranged so that a portion of the second pump optical signal backscattered by the ring optical resonator propagates back to the second pump laser source and injection-locks the second pump laser source so that the second pump optical frequency v 2P is locked to a second resonant mode optical frequency of the ring optical resonator different from the first resonant mode optical frequency; and

(d) an optical frequency divider arranged so as (i) to receive at least a portion of the first pump optical signal and at least a portion of the second pump optical signal, and (ii) to generate therefrom an electrical output signal at a divided frequency about equal to |v 2P −v 1P |/N, with N being an integer and |v 2P −v 1P | being greater than 100 GHz.

12 . The apparatus of claim 11 wherein the divided frequency is greater than 0.3 GHz.

13 . The apparatus of claim 11 wherein (i) the difference frequency v DIFF =|v 2 −v 1 | exhibits fluctuations over a 0.1 second timescale only within a bandwidth less than 100 Hz, or (ii) the output electrical signal exhibits phase noise less than −80-20·logN dBc/Hz at 10 KHz offset frequency.

14 . The apparatus of claim 11 wherein (i) the difference frequency v DIFF =|v 2 −v 1 | exhibits fluctuations over a 0.1 second timescale only within a bandwidth less than 1 Hz, or (ii) the output electrical signal exhibits phase noise less than −100-20·logN dBc/Hz at 10 KHz offset frequency.

15 . The apparatus of claim 11 wherein one or both of the first or second pump lasers sources are semiconductor diode lasers.

16 . The apparatus of claim 11 wherein one or both of the first or second pump optical frequencies v 1P and v 2P are greater than 75 THz or less than 750 THz.

17 . The apparatus of claim 11 wherein the ring optical resonator comprises a ring waveguide optical resonator on a substrate.

18 . The apparatus of claim 11 wherein the ring optical resonator comprises a disk optical resonator.

19 . The apparatus of claim 11 wherein the ring optical resonator comprises a fiber-loop optical resonator.

20 . The apparatus of claim 11 wherein the optical resonator exhibits a Q-factor greater than 10 6 .

21 . An apparatus comprising:

(a) a ring optical resonator;

(b) a first pump laser source arranged so as to (i) produce a first pump optical signal at a first pump optical frequency v 1P , and (ii) launch at least a portion of the first pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the first pump laser source being arranged so that a portion of the first pump optical signal backscattered by the ring optical resonator propagates back to the first pump laser source and injection-locks the first pump laser source so that the first pump optical frequency v 1P is locked to a first resonant mode optical frequency of the ring optical resonator; and

(c) a second pump laser source arranged so as to (i) produce a second pump optical signal at a second pump optical frequency v 2P , and (ii) launch at least a portion of the second pump optical signal into the ring optical resonator to propagate in a forward direction around the ring optical resonator, the ring optical resonator and the second pump laser source being arranged so that a portion of the second pump optical signal backscattered by the ring optical resonator propagates back to the second pump laser source and injection-locks the second pump laser source so that the second pump optical frequency v 2P is locked to a second resonant mode optical frequency of the ring optical resonator different from the first resonant mode optical frequency,

(d) wherein one or both of the first or second pump optical frequencies v 1P and v 2P are greater than 75 THz or less than 750 THz.

22 . The apparatus of claim 21 wherein one or both of the first or second pump lasers sources are semiconductor diode lasers.

23 . The apparatus of claim 21 wherein the ring optical resonator comprises a ring waveguide optical resonator on a substrate.

24 . The apparatus of claim 21 wherein the ring optical resonator comprises a disk optical resonator.

25 . The apparatus of claim 21 wherein the ring optical resonator comprises a fiber-loop optical resonator.

26 . The apparatus of claim 21 wherein the optical resonator exhibits a Q-factor greater than 10 6 .

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 19, 2023
From: LI, JIANG; VAHALA, KERRY
To: HQPHOTONICS INC.
Reel/Frame 062428/0953 →
Continuity (1)
Provisional Application 63300524 · Jan 18, 2022
References Cited (38)
US 9450673B2 · Vahala et al. · 2016 [cited by applicant]
US 9537571B2 · Li et al. · 2017 [cited by applicant]
US 9905999B2 · Li et al. · 2018 [cited by applicant]
US 11486706B2 · Wu · 2022 [cited by examiner]
US 11804694B2 · Bilenko · 2023 [cited by examiner]
US 20120039346A1 · Liang · 2012 [cited by examiner]
US 20170302048A1 · Li · 2017 [cited by examiner]
US 20190341739A1 · Loh · 2019 [cited by examiner]
US 20200313389A1 · Bilenko · 2020 [cited by examiner]
US 20220026211A1 · Wu · 2022 [cited by examiner]
US 20240322522A1 · Kippenberg · 2024 [cited by examiner]
Drever, R. et al; Laser phase and frequency stabilization using an optical resonator; Applied Physics B 31, 97 105 (1983). [cited by applicant]
Hansch, T. & Couillaud, B.; Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity; Optics communications 35, 441 444 (1980). [cited by applicant]
Young, B., Cruz, F., Itano, W. & Bergquist, J.; Visible lasers with subhertz linewidths; Physical Review Letters; 82, 3799 (1999). [cited by applicant]
Jin, W. et al.: Hertz-linewidth semiconductor lasers using CMOS-ready ultra-high-Q microresonators; Nature Photonics 15, 346-353 (2021). [cited by applicant]
Li, B. et al; Reaching fiber-laser coherence in integrated photonics; Optics Letters 46, 5201 5204 (2021). [cited by applicant]
Shen, B. et al; Integrated turnkey soliton microcombs; Nature 582, 365 369 (2020). [cited by applicant]
Stokes, L., Chodorow, M. & Shaw, H.; All-fiber stimulated Brillouin ring laser with submilliwatt pump threshold; Optics Letters 7, 509 511 (1982). [cited by applicant]
Smith, S., Zarinetchi, F. & Ezekiel, S. Narrow-linewidth stimulated Brillouin fiber laser and applications; Optics letters 16, 393 395 (1991). [cited by applicant]
Geng, J. et al; Highly stable low-noise Brillouin fiber laser with ultranarrow spectral linewidth; IEEE Photonics Technology Letters 18, 1813 1815 (2006). [cited by applicant]
Lee, H. et al; Chemically etched ultrahigh-Q wedge-resonator on a silicon chip; Nature Photonics 6, 369 373 (2012). [cited by applicant]
Li, J., Lee, H., Chen, T. & Vahala, K. J.; Characterization of a high coherence, Brillouin microcavity laser on silicon; Optics Express 20, 20170 20180 (2012). [cited by applicant]
Pant, R. et al; On-chip stimulated Brillouin scattering; Optics express 19, 8285 8290 (2011). [cited by applicant]
Debut, A., Randoux, S. & Zemmouri, J.; Linewidth narrowing in Brillouin lasers: Theoretical analysis; Physical Review A 62, 023803 (2000). [cited by applicant]
Gundavarapu, S. et al; Sub-hertz fundamental linewidth photonic integrated Brillouin laser; Nature Photonics 13, 60 67 (2019). [cited by applicant]
Fortier, T. M. et al; Generation of ultrastable microwaves via optical frequency division; Nature Photonics 5, 425 429 (2011). [cited by applicant]
Swann, W. C., Baumann, E., Giorgetta, F. R. & Newbury, N. R.; Microwave generation with low residual phase noise from a femtosecond fiber laser with an intracavity electro-optic modulator; Optics express 19, 24387 24395… [cited by applicant]
Li, J., Yi, X., Lee, H., Diddams, S. A. & Vahala, K. J.; Electro-optical frequency division and stable microwave synthesis; Science 345, 309 313 (2014). [cited by applicant]
Li, J. & Vahala, K.; A 30 GHz ultra-low-phase-noise oscillator using electro-optical frequency division; 2017 IEEE Photonics Conference (IPC) (2017), 455 456. [cited by applicant]
Kippenberg, T. J., Gaeta, A. L., Lipson, M. & Gorodetsky, M. L.; Dissipative Kerr solitons in optical microresonators; Science 361 (2018). [cited by applicant]
Lee, H. et al.; Spiral resonators for on-chip laser frequency stabilization; Nature Communications 4, 1 6 (2013). [cited by applicant]
Bauters, J. F. et al; Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding; Optics Express 19, 24090 24101 (2011). [cited by applicant]
Kondratiev, N. et al; Self-injection locking of a laser diode to a high-Q WGM microresonator; Optics Express 25, 28167 28178 (2017). [cited by applicant]
Wang, H., Wu, L., Yuan, Z. & Vahala, K.; Towards milli-Hertz laser frequency noise on a chip; CLEO: Science and Innovations (2021), SF2O 2. [cited by applicant]
Li, Jiang, Hansuek Lee, and Kerry J. Vahala; “Low-noise Brillouin laser on a chip at 1064 nm”; Optics Letters 39(2) 287-290 (2014). [cited by applicant]
Spirin et al; “Single-mode Brillouin fiber laser passively stabilized at resonance frequency with self-injection locked pump laser”; Laser Physics Letters 9(5) 377-380 (2012). [cited by applicant]
Spirin et al; “Stabilizing DFB laser injection-locked to an external fiber-optic ring resonator”; Optics Express 28(1) 478 (2020). [cited by applicant]
Korobko et al; “Self-injection-locking linewidth narrowing in a semiconductor laser coupled toring resonator”; Optics Communications 405 253-258 (2017). [cited by applicant]