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

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.