Single-frequency Brillouin fiber ring laser with extremely narrow linewidth
First Claim
1. A Brillouin fiber ring laser, comprising:
- A Brillouin fiber ring cavity having at least one cavity mode within the Brillouin gain profile;
A tunable pump laser that emits a single-frequency pump beam that is optically coupled to the ring cavity; and
A feedback loop comprising a function generator that applies a dither signal to the pump laser frequency, said feedback loop actively tuning the pump laser to keep the frequency of the pump beam in resonance with one of said at least one cavity modes so that the cavity emits a single-frequency Brillouin laser beam at a different wavelength and having a different linewidth at least one order of magnitude narrower than the linewidth of said single-frequency pump beam.
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Abstract
A single-frequency Brillouin fiber ring laser with extremely narrow linewidth comprises a single-frequency narrow-linewidth rapid-tunable pump laser, a temperature-controlled acoustically-damped package for Brillouin fiber ring laser cavity, and an auto-tracking feedback electronic loop with novel configuration for active stabilization. The Pound-Drever-Hall frequency-locking technique is employed to keep pump laser frequency in resonance with one of the Brillouin fiber ring cavity modes. Instead of changing cavity length of Brillouin fiber ring laser, the pump laser frequency is rapidly tuned in the auto-tracking feedback electronic loop. This enables extremely narrow linewidth radiation emitted from a Brillouin fiber ring laser without stretching the fiber ring. Dual-wavelength actively stabilized Brillouin fiber ring laser may be generated from a single ring cavity by polarization-combining or wavelength-combining two pump laser beams and using two independent feedback loops to the two operation wavelengths.
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Citations
15 Claims
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1. A Brillouin fiber ring laser, comprising:
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A Brillouin fiber ring cavity having at least one cavity mode within the Brillouin gain profile; A tunable pump laser that emits a single-frequency pump beam that is optically coupled to the ring cavity; and A feedback loop comprising a function generator that applies a dither signal to the pump laser frequency, said feedback loop actively tuning the pump laser to keep the frequency of the pump beam in resonance with one of said at least one cavity modes so that the cavity emits a single-frequency Brillouin laser beam at a different wavelength and having a different linewidth at least one order of magnitude narrower than the linewidth of said single-frequency pump beam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A Brillouin fiber ring laser, comprising:
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A Brillouin fiber ring cavity having at least one cavity mode within the Brillouin gain profile; A tunable pump laser that emits a single-frequency pump beam that is optically coupled to the ring cavity; A function generator that applies a dither signal to the pump laser frequency; A detector that detects an intensity modulated portion of the pump beam coupled out of the ring cavity; and A demodulator that demodulates the intensity modulated portion of the pump beam to provide an error signal that actively tunes the pump laser frequency to keep the frequency of the pump beam in resonance with one of said at least one cavity modes so that the cavity emits a single-frequency Brillouin laser beam at a different wavelength and having a different linewidth at least one order of magnitude narrower than the linewidth of said single-frequency pump beam. - View Dependent Claims (10, 11)
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12. A method for actively stabilizing a Brillouin fiber ring laser, comprising:
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Using a tunable single-frequency pump laser that emits a single frequency pump beam to pump a Brillouin fiber ring cavity having at least one cavity mode within the Brillouin gain profile; Dithering the pump laser frequency leaving the ring cavity undisturbed; Detecting an intensity modulated portion of the pump beam coupled out of the ring cavity; Demodulating the intensity modulated portion of the pump to provide an error signal; and Feeding back the error signal to actively tune the pump laser to keep the frequency of the pump beam in resonance with one of the ring cavity modes so that the cavity emits a single-frequency Brillouin laser beam at a different wavelength and having a linewidth at least one order of magnitude narrower than the linewidth of said single-frequency pump beam. - View Dependent Claims (13, 14, 15)
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Specification