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Generation and Coherent Control of Pulsed Quantum Frequency Combs
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Synchronization of frequency combs by optical injection
Optics Express
|October 19, 2022
Summary
Stabilizing offset frequencies in semiconductor laser optical frequency combs is crucial for dual-comb spectroscopy. This study demonstrates synchronized offset frequencies using optical injection locking, enabling phase-stabilized dual-comb spectrometers.
Area of Science:
- Optics and Photonics
- Spectroscopy
- Laser Physics
Background:
- Semiconductor laser optical frequency combs offer monolithic integration for dual-comb spectrometers.
- Stabilizing the offset frequency (fceo) is challenging due to limited spectral bandwidth, causing signal degradation and complex processing.
- Current dual-comb configurations suffer from uncorrelated frequency jitter, leading to broadened beatnotes and low signal-to-noise ratios (SNR).
Purpose of the Study:
- To demonstrate a novel method for synchronizing the offset frequencies of two optical frequency combs.
- To achieve full phase-stabilization in dual-comb spectrometers by combining optical and electrical injection locking.
- To enable simpler data acquisition and processing for dual-comb spectroscopy.
Main Methods:
- Utilizing optical injection locking with a master oscillator derived from a single comb line isolated by an optical Vernier filter.
- Implementing electrical injection locking for the repetition frequencies (frep) of both combs.
- Employing analog electronics for coherent averaging of the stabilized dual-comb signal.
Main Results:
- Achieved synchronized and phase-stabilized offset frequencies for two optical frequency combs.
- Demonstrated a periodic and stable dual-comb signal over thousands of periods.
- Significantly increased SNR by orders of magnitude and reduced data size, enabling efficient coherent averaging.
Conclusions:
- The presented optical injection locking technique enables fully phase-stabilized dual-comb spectrometers.
- This method simplifies data acquisition and processing, reducing hardware complexity and cost.
- Provides a pathway for comparing and stabilizing offset frequencies to narrow-linewidth optical references.
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