Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Applied

Robust suppression of high-frequency laser phase noise by adaptive Pound-Drever-Hall feedforward

Yu-Xin Chao, Zhen-Xing Hua, Xin-Hui Liang, Zong-Pei Yue, Jia Chen, Li You, Meng Khoon Tey

Published Jan 27, 2025• 10 citations
Publisher

Abstract

As opposed to feedback, feedforward methods bring new opportunities to suppress high-frequency laser phase noise, but their performance is more susceptible to environmental perturbations, hindering broad application. Tackling the key factors for long-term stability of feedforward based on Pound-Drever-Hall (PDH) detection, the authors construct a compact circuit to adaptively control feedforward gain in response to power variations of cavity transmission. This design achieves robust suppression beyond 40 dB for megahertz noise frequencies. The compact scheme may promote the general use of reliable PDH feedforward in simple, inexpensive lasers for precision quantum control and metrology.

DOI
10.1103/physrevapplied.23.l011005

Related papers

Robust High-frequency Laser Phase Noise Suppression by Adaptive Pound-Drever-Hall Feedforward

Yu-Xin Chao, Zhen-Xing Hua, Xin-Hui Liang +4 more

Suppressing high-frequency laser phase noise, particularly at frequencies near and beyond typical feedback bandwidths of a few MHz, is a critical yet challenging task in many advanced applications. Feedforward-based methods generally outperform feedback in high-frequency range, but their performances are more susceptible to perturbations. In this work, we focus on the Pound-Drever-Hall (PDH)-feedforward method we demonstrated recently [Yu-Xin Chao et al., Optica 11(7), 945-950 (2024)] and analyze the factors that affect its long-term stability. By constructing a simple circuit allowing for adaptive control of the feedforward gain in response to power fluctuations of cavity transmission, we demonstrate a robust $\geq 40$ dB suppression of laser phase noise around 2 MHz and a noise suppression bandwidth up to 50 MHz. In comparison, when using normal PDH feedback, robust noise suppression of over 40 dB can only occur for frequencies below tens of kHz in most setups. Our findings may pave the way for general usage of PDH feedforward and allow for simple construction of low-noise lasers for precise quantum controls and precision metrology.

arXiv:2407.19642•Jul 29, 2024•0 citations

Pound-Drever-Hall Feedforward for Trapped-Ion Optical Qubits

Jia-Yang Gao, Jianwei Lee, Morteza Ahmadi +1 more

Laser phase noise is one of the limiting factors that dictate gate fidelities and coherence times in trapped-ion quantum systems. Previous studies have reported that when the Rabi frequency of an ion qubit is close to the servo-bump phase-noise frequency, the driving laser limits the fidelity and coherence time. This issue has typically been mitigated by choosing a Rabi frequency outside the servo-bump region. However, this constrains the usable range of gate speeds and can limit the achievable fidelity. To address this issue, we developed an active phase-noise stabilization system for a barium-ion optical-qubit laser at 1762 nm, employing a fiber electro-optic modulator (EOM) with an electrical feedforward servo. Our results demonstrate that this setup, based on the Pound-Drever-Hall (PDH) feedforward method, can suppress servo-bump phase noise by 15 dB near the bump peak frequency in our locking system. The laser phase noise is analyzed using delayed self-heterodyne interferometry (DSHI). We further tested the stabilized laser on an optical qubit and observed a clear improvement in coherence time based on the measured amplitude decay of Rabi oscillations, even when the Rabi frequency lies within the servo-bump bandwidth. This technique can be readily adapted to other optical qubits with minimal modifications.

quant-pharXiv:2607.24050•Jul 28, 2026•0 citations

Predictive electronic feedback control for narrow-linewidth lasers

Jiatian Liu, Xuan Qi, Xiayang Fan +2 more

Narrow-linewidth lasers are essential for various key atom-laser interaction processes and optical setups in quantum coherent control, quantum precision measurement, and quantum information science. The Pound-Drever-Hall (PDH) technique is the standard method for the frequency-stabilization of narrow-linewidth lasers, but the inherent time delay in its feedback loop inevitably induces excessive phase noise, commonly known as servo bumps. Previous solutions primarily rely on additional optical components outside the electronic feedback control loop. Here, we propose and implement a generic method based on the Smith predictor to address the time-delay issue entirely within the electronic part of the PDH feedback control loop. We systematically demonstrate its capability to suppress phase noise and reduce servo bumps by adding only a single Field-Programmable Gate Array (FPGA) controller to the loop. This class of methods is demonstrated to be conceptually concise with minimal hardware overhead, effective in practice, and holds potential for a wide variety of future applications.

physics.opticsCross-listedarXiv:2610.31396•Oct 23, 2026

Robust cavity metrology beyond the limits of Pound-Drever-Hall

Ibukunoluwa Adisa, Won Chan Lee, Yanqin Huang +3 more

Precise measurement of the resonance frequencies of microwave and optical cavities is a foundational capability across quantum technologies. One of the highest-performance methods currently available is Pound-Drever-Hall (PDH) spectroscopy, which relies on a three-tone interrogation and eliminates sensitivity to path-length fluctuations. However, PDH is known to suffer from systematic offsets due to residual amplitude modulation and demodulation-phase errors. Here we leverage an optimal linear combination of the phases of the three interrogation tones to implement a method for robust cavity metrology which eliminates significant systematic-error sensitivities of PDH. We experimentally demonstrate robust cavity measurements in both the optical and microwave frequency regime, showing insensitivity to sideband imbalance and demodulation phase, as well as demonstrating single-shot readout of a cavity-coupled superconducting qubit.

quant-pharXiv:2608.21512•Aug 25, 2026•0 citations

High-bandwidth Coherence Cloning using Optical-Phase-Locking Feedforward

Chen Jia, Zhen-Xing Hua, Yu-Xin Chao +1 more

Ultra-narrow-linewidth lasers with suppressed high-frequency phase noise are critical for quantum control and precision metrology. While optical phase locking (OPL) is the standard technique for cloning the coherence of such sources, its effectiveness is often limited at high frequencies by feedback latency. We present a robust feedforward architecture that overcomes this limitation by recycling and demodulating the existing master-slave beat signal to drive a single electro-optic modulator for near-instantaneous noise cancellation. This approach eliminates the extraneous sidebands and transmission losses typical of more complex modulators. Through active stabilization of the beat amplitude and demodulation phase, we demonstrate robust suppression exceeding 30 dB from 10 kHz to 10 MHz. This hardware-efficient framework is readily compatible with standard OPL setups, offering a scalable solution for high-fidelity coherent control.

quant-pharXiv:2604.02218•Apr 3, 2026•0 citations

Stabilization of $866$ nm laser with Pound-Drever-Hall (PDH) technique for quantum manipulation of Ca+ ion in Paul trap

Siddhant Singh

This article provides an introduction to one of the most efficient laser stabilization techniques - the Pound-Drever-Hall (PDH) method. The aim of the experiment is to build the PDH stabilization apparatus from scratch. I describe all the necessary theoretical treatment to formulate the technique and then describe it as I have experimentally implemented in the lab. All major sources of noise are discussed and noise tackling methods are implemented. All the equipments used are also described in detail for their principle and working.

arXiv:2007.00768•Jun 25, 2020•1 citation
As opposed to feedback, feedforward methods bring new opportunities to suppress high-frequency laser phase noise, but their performance is more susceptible to environmental perturbations, hindering broad application. Tackling the key factors for long-term stability of feedforward based on Pound-Drever-Hall (PDH) detection, the authors construct a compact circuit to adaptively control feedforward gain in response to power variations of cavity transmission. This design achieves robust suppression beyond 40 dB for megahertz noise frequencies. The compact scheme may promote the general use of reliable PDH feedforward in simple, inexpensive lasers for precision quantum control and metrology.
Suppressing high-frequency laser phase noise, particularly at frequencies near and beyond typical feedback bandwidths of a few MHz, is a critical yet challenging task in many advanced applications. Feedforward-based methods generally outperform feedback in high-frequency range, but their performances are more susceptible to perturbations. In this work, we focus on the Pound-Drever-Hall (PDH)-feedforward method we demonstrated recently [Yu-Xin Chao et al., Optica 11(7), 945-950 (2024)] and analyze the factors that affect its long-term stability. By constructing a simple circuit allowing for adaptive control of the feedforward gain in response to power fluctuations of cavity transmission, we demonstrate a robust ≥40\geq 40≥40 dB suppression of laser phase noise around 2 MHz and a noise suppression bandwidth up to 50 MHz. In comparison, when using normal PDH feedback, robust noise suppression of over 40 dB can only occur for frequencies below tens of kHz in most setups. Our findings may pave the way for general usage of PDH feedforward and allow for simple construction of low-noise lasers for precise quantum controls and precision metrology.
Laser phase noise is one of the limiting factors that dictate gate fidelities and coherence times in trapped-ion quantum systems. Previous studies have reported that when the Rabi frequency of an ion qubit is close to the servo-bump phase-noise frequency, the driving laser limits the fidelity and coherence time. This issue has typically been mitigated by choosing a Rabi frequency outside the servo-bump region. However, this constrains the usable range of gate speeds and can limit the achievable fidelity. To address this issue, we developed an active phase-noise stabilization system for a barium-ion optical-qubit laser at 1762 nm, employing a fiber electro-optic modulator (EOM) with an electrical feedforward servo. Our results demonstrate that this setup, based on the Pound-Drever-Hall (PDH) feedforward method, can suppress servo-bump phase noise by 15 dB near the bump peak frequency in our locking system. The laser phase noise is analyzed using delayed self-heterodyne interferometry (DSHI). We further tested the stabilized laser on an optical qubit and observed a clear improvement in coherence time based on the measured amplitude decay of Rabi oscillations, even when the Rabi frequency lies within the servo-bump bandwidth. This technique can be readily adapted to other optical qubits with minimal modifications.
Narrow-linewidth lasers are essential for various key atom-laser interaction processes and optical setups in quantum coherent control, quantum precision measurement, and quantum information science. The Pound-Drever-Hall (PDH) technique is the standard method for the frequency-stabilization of narrow-linewidth lasers, but the inherent time delay in its feedback loop inevitably induces excessive phase noise, commonly known as servo bumps. Previous solutions primarily rely on additional optical components outside the electronic feedback control loop. Here, we propose and implement a generic method based on the Smith predictor to address the time-delay issue entirely within the electronic part of the PDH feedback control loop. We systematically demonstrate its capability to suppress phase noise and reduce servo bumps by adding only a single Field-Programmable Gate Array (FPGA) controller to the loop. This class of methods is demonstrated to be conceptually concise with minimal hardware overhead, effective in practice, and holds potential for a wide variety of future applications.
Precise measurement of the resonance frequencies of microwave and optical cavities is a foundational capability across quantum technologies. One of the highest-performance methods currently available is Pound-Drever-Hall (PDH) spectroscopy, which relies on a three-tone interrogation and eliminates sensitivity to path-length fluctuations. However, PDH is known to suffer from systematic offsets due to residual amplitude modulation and demodulation-phase errors. Here we leverage an optimal linear combination of the phases of the three interrogation tones to implement a method for robust cavity metrology which eliminates significant systematic-error sensitivities of PDH. We experimentally demonstrate robust cavity measurements in both the optical and microwave frequency regime, showing insensitivity to sideband imbalance and demodulation phase, as well as demonstrating single-shot readout of a cavity-coupled superconducting qubit.
Ultra-narrow-linewidth lasers with suppressed high-frequency phase noise are critical for quantum control and precision metrology. While optical phase locking (OPL) is the standard technique for cloning the coherence of such sources, its effectiveness is often limited at high frequencies by feedback latency. We present a robust feedforward architecture that overcomes this limitation by recycling and demodulating the existing master-slave beat signal to drive a single electro-optic modulator for near-instantaneous noise cancellation. This approach eliminates the extraneous sidebands and transmission losses typical of more complex modulators. Through active stabilization of the beat amplitude and demodulation phase, we demonstrate robust suppression exceeding 30 dB from 10 kHz to 10 MHz. This hardware-efficient framework is readily compatible with standard OPL setups, offering a scalable solution for high-fidelity coherent control.
Stabilization of 866866866 nm laser with Pound-Drever-Hall (PDH) technique for quantum manipulation of Ca+ ion in Paul trap
This article provides an introduction to one of the most efficient laser stabilization techniques - the Pound-Drever-Hall (PDH) method. The aim of the experiment is to build the PDH stabilization apparatus from scratch. I describe all the necessary theoretical treatment to formulate the technique and then describe it as I have experimentally implemented in the lab. All major sources of noise are discussed and noise tackling methods are implemented. All the equipments used are also described in detail for their principle and working.