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

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 × 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 × 10−7 at 100 s averaging time. Above 100 s, the instability increases and reaches 2 × 10−6 at 10 000 s.

Ultra-low intensity noise, all fiber 365 W linearly polarized single frequency laser at 1064 nm

“…shows the Allan deviation (log-log plot) of the power fluctuations expressed in percent of the normalized optical power respect to the measurement time. In order to better analyze this long-term time series, we have processed the data using the Allan deviation, a statistical tool widely used by the time and frequency community [39] and more recently applied to the characterization of the optical power stability [40]. Figure 8.…”

Long-Term Stability Analysis Toward <10−14 Level for a Highly Compact POP Rb Cell Atomic Clock

“…For reducing these long-term instability contributions due to light intensity fluctuations, active laser intensity stabilization is required and can be implemented by, e.g., acting on the laser temperature or via the AOM drive power. Considering that the relative laser intensity fluctuations may be drastically reduced down to the level of 2 × 10 −6 at τ = 10 4 s [39] with a stabilization loop via the RF power of the employed AOM, our clock's instability contribution from the intensity LS effect would improve by more than three orders of magnitude to the 5 × 10 −18 level. Besides decreasing the laser intensity fluctuations, detailed investigation on the processes contributing to the LSs in the POP scheme, particularly in view of reducing the residual coherence via a stronger optical pumping [37] would help to improve the clock stability limits due to this effect.…”

Metrological and stability studies in high-performance rubidium vapor-cell atomic clocks

“…The laser frequency is stabilized via the laser drive current, and therefore may lead to light intensity variations if the intensity is not stabilized in a separate loop. The laser intensity fluctuations can be reduced through an active stabilization loop via the AOM [115] up to three orders of magnitude, yielding a clock stability limit below 10 −16 . Nevertheless, adding a servo loop on each parameter would make the system relatively more complicated and power consuming.…”

“…Given that the relative laser intensity fluctuations can be drastically reduced to the level of 2 • 10 −5 at τ = 10 4 s using a temperature-stabilized AOM, as demonstrated in. [115], with a stabilization loop via the RF power of the employed AOM, our clock's stability limit of the intensity LS effect would decrease by more than three orders of magnitude to 5 • 10 −17 . In addition to decreasing the laser intensity fluctuations, detailed investigation of the processes that contribute to the light shifts in the POP scheme, particularly in view of reducing the residual coherence via a stronger optical pumping [69], would help to improve the clock stability limits due to this effect.…”

“…In the POP-DR scheme, the AOM required for optical switching would further degrade the output power stability by about one order of magnitude (see Table 2.1). Therefore, an active optical power stabilization should be considered to restrain the limitations to clock stability, with a potential of several orders of magnitude improvement in power stability [115], thus the clock stability limit for unchanged intensity LS coefficient.…”