Optics Letters

Passive laser power stabilization in a broadband noise spectrum via a second-harmonic generator

Nanjing Jiao, Ruixin Li, Bingnan An, Jiawei Wang, Lirong Chen, Yajun Wang, Yaohui Zheng

Published May 24, 2024• 10 citations

Abstract

An extremely conspicuous passive power noise stabilization is the first, to the best of our knowledge, discovered in a cavity-enhanced second-harmonic generation (SHG) process. Differing from the SHG as a buffer reservoir, the stronger strength of the nonlinear interaction pushes the power noise suppression level to a higher value and exhibits a broadband noise reduction performance due to the mechanism of dynamic pump suppression in the SHG process. The noise is suppressed to near shot noise limit (SNL) among the kHz to MHz frequency range, accompanied by a maximum noise reduction of 35 dB. A comprehensive demonstration indicates that the nonlinear interaction has no function on the phase noise of fundamental and harmonic waves. A theoretical model is also established that is consistent well with the experimental results. The methodology is beneficial to multiple optical metrology experiments.

DOI: 10.1364/ol.524119

Related papers

Bright squeezed light in the kilohertz frequency band

Ruixin Li, Bingnan An, Nanjing Jiao +4 more

The dominant technical noise of a free-running laser practically limits bright squeezed light generation, particularly within the MHz band. To overcome this, we develop a comprehensive theoretical model for nonclassical power stabilization, and propose a novel bright squeezed light generation scheme incorporating hybrid power noise suppression. Our approach integrates broadband passive power stabilization with nonclassical active stabilization, extending the feedback bandwidth to MHz frequencies. This hybrid technique achieves an additional 9 dB technical noise suppression, establishing critical prerequisites for broadband bright squeezed light generation. Finally, a -5.5 dB bright squeezed light at 1 mW with kHz-MHz squeezing bandwidth was generated. The experimental results show excellent agreement with theoretical predictions, which represent we have comprehensively demonstrated a milliwatt-order bright squeezed light across kHz-MHz frequencies. Our work enables new quantum metrology applications and paves the way for next-generation quantum-enhanced technologies. Nonclassical hybrid passive-active power stabilization enables milliwatt-level bright squeezing across kHz-MHz band.

arXiv:2504.00627Light Science & ApplicationsSep 8, 202520 citations

Broadband suppression of laser intensity noise based on second-harmonic generation

Y. Li, F. Seddighi, Gil Porat

We present a novel method for the suppression of laser intensity noise and pulse-to-pulse energy fluctuation, based on second-harmonic generation. This method is broadband, passive, has low complexity, and suppresses noise uniformly over the noise spectrum. We theoretically model, analytically analyze, and numerically simulate this technique's performance for cw and nanosecond pulse lasers with different pulse shapes. We demonstrate broadband relative intensity noise suppression of up to 48 dB, and pulse-to-pulse energy fluctuation suppression of up to 50 dB, and highlight the significance of these findings for extending atom trap storage time, e.g., for quantum information processing.

Physical Review AppliedJul 11, 20244 citations

Fiber-interferometric second harmonic generator with dual-color standard quantum-limited noise performance

Marvin Edelmann, Mikhail Pergament, Yi Hua +2 more

We present a novel fiber-interferometric device that achieves dual functionality: simultaneous amplification of the pulsed input signal and generation of its second harmonic while effectively suppressing the intensity noise in both modes, reaching the standard quantum-limit. The underlaying mechanism is based on phase-biased nonlinear polarization rotation coupled with type-I phase-matched second harmonic generation, a concept that is both theoretically investigated and experimentally verified. In the experiment, a fiber-optic system is constructed capable of generating 42 MHz ultra-low noise sub-150 fs output pulse trains simultaneously at 1030 nm and 515 nm, with average powers of 165 mW and 50 mW, respectively. Systematic frequency-resolved intensity noise measurements confirm dual wavelength, quantum-limited noise suppression beyond 100 kHz offset-frequency, with suppression levels up to 14 dB, showing correlation with local maxima in average power in both fundamental and second harmonic mode.

Optics ExpressFeb 20, 20240 citations

Bright squeezed light generation via nonclassical power stabilization

Jasper R. Venneberg, H. Vahlbruch, Marina Trad Nery +1 more

Low-power-noise lasers are essential for many high-precision experiments. Shot noise imposes a fundamental limit on the power stability achievable with classical light sources. In this Letter, we report the generation of bright squeezed light in the audio band, which can improve the sensitivity of otherwise shot-noise-limited measurements. The bright squeezed light source is experimentally realized via the use of squeezed vacuum in a power stabilization scheme. We demonstrate a laser beam at a power of 9.9 mW with a broadband power noise suppression below the classical stabilization limit by up to 8 . 7 − 0.4 + 0.3 dB in the audio band, resulting in a bright squeezed beam with a power noise of 5 . 7 − 0.4 + 0.3 dB below shot noise for frequencies from 6 kHz to 20 kHz. We further conceptually outline a method to surpass this result in the future.

Physical Review ResearchMay 20, 20257 citations

Ultrabroadband Passive Laser Noise Suppression to Quantum Noise Limit through on-chip Second Harmonic Generation

Geun Ho Ahn, Ziyu Wang, Devin J. Dean +5 more

Laser intensity noise limits performance in quantum sensing, metrology, and computing. Existing stabilization methods face a trade-off between bandwidth and complexity: electronic feedback loops are speed-limited, while optical resonators are constrained by narrow linewidths and locking requirements. Here, we demonstrate an all-optical "noise eater" that passively suppresses intensity fluctuations from DC to >10 gigahertz. By leveraging high-efficiency second-harmonic generation in nanophotonic lithium niobate waveguides, we operate at a pump-depletion stationary point where input fluctuations are decoupled from the output to first order. This passive and nonresonant nanophotonic device suppresses relative intensity noise by 25 to 60 dB over the full measurement bandwidth and stabilizes a noisy fiber amplifier output to the shot-noise limit. Our results establish a scalable, wide-bandwidth paradigm for laser stabilization essential for high-throughput quantum technologies and deployable photonic sensing systems.

physics.opticsCross-listedarXiv:2603.25801Mar 30, 20260 citations

Ultrabroadband Passive Laser Noise Suppression to Quantum Noise Limit via on-chip Second Harmonic Generation

Amir H. Safavi‐Naeini, Geun Ho Ahn, Ziyu Wang +5 more

Abstract Laser intensity noise limits performance in quantum sensing, metrology, and computing. Existing stabilization methods face a trade-off between bandwidth and complexity: electronic feedback loops are speed-limited, while optical resonators are constrained by narrow linewidths and locking requirements. Here, we demonstrate an all-optical "noise eater" that passively suppresses intensity fluctuations from DC to > 10 gigahertz. By leveraging high-efficiency second-harmonic generation in nanophotonic lithium niobate waveguides, we operate at a pump-depletion stationary point where input fluctuations are decoupled from the output to first order. This passive and nonresonant nanophotonic device suppresses relative intensity noise by 25 to 60 dB over the full measurement bandwidth and stabilizes a noisy fiber amplifier output to the shot-noise limit. Our results establish a scalable, wide-bandwidth paradigm for laser stabilization essential for high-throughput quantum technologies and deployable photonic sensing systems.

Mar 25, 20260 citations