Power stabilization of a diode laser with an acousto-optic modulator

TLDR

Laser power fluctuations degrade device performance, with high‑frequency variations lowering signal‑to‑noise ratio and slow drifts reducing repeatability or accuracy. The study experimentally investigates power stabilization of a diode laser using an acousto‑optic modulator. Stabilization is achieved by modulating the laser with an AOM, and slow power variations are examined in the time domain. The system reduces relative power noise to 2.2 × 10⁻⁸ Hz⁻¹ᐟ² over 1–100 kHz, yields an Allan deviation of 6 × 10⁻⁷ at 100 s that grows to 2 × 10⁻⁶ at 10 000 s.

Abstract

Laser power fluctuations can significantly reduce the device performances in various applications. High frequency fluctuations impact the signal-to-noise ratio, while slow variations can reduce the device repeatability or accuracy. Here we report experimental investigations on the power stabilization of a diode laser with an acousto-optic modulator. In the frequency domain the relative power noise is reduced at the level of $2.2\times 10^{-8}$ Hz$^{-1/2}$ in the range 1-100 kHz. The slow variations are studied in the time domain. The relative Allan standard deviation is measured at the level of $6\times 10^{-7}$ at 100 s averaging time. Above 100 s the instability increases and reaches $2 \times 10^{-6}$ at 10 000 s.