Suppression of residual amplitude modulation effects in Pound–Drever–Hall locking

Abstract

Residual amplitude modulation (RAM) effects in a Pound-Drever-Hall (PDH) technique locked cavity system is analyzed in this paper. The suppression of the amplitude of the RAM has been investigated by many groups, while the effect of the cavity response has not received full attention. Frequency shift caused by RAM in the PDH method is found to be both related to the amplitude of the RAM effects and to the cavity's mode matching and impedance matching. According to our analysis, RAM effects can be fully suppressed by choosing proper impedance matching parameter and magic mode coupling efficiency. We measure the RAM-to-frequency conversion coefficients at different coupling efficiencies. The result agrees well with our theoretical model, demonstrating the potential of full suppression of the RAM effects through proper design of cavities.

New method for residual amplitude modulation control in fibered optical experiments

“…This is consistent with the fact that V ε (ϕ d + π/2) monitors the RAM amplitude, which is proportional to sin(δϕ) according to Eqs. (15)(16)(17) (see also the Supplementary). Again, the theoretical curves perfectly agree with the measured ones.…”

“…This method has been shown to be very efficient when there is no polarization dependent component on the two beam paths, for instance when both beams propagate in free space [4,8,11]. Several studies, based on this technique, propose complementary approaches to actively or passively compensate the RAM effect [14][15][16][17][18][19].…”

Noise Analysis of a Passive Resonant Laser Gyroscope

“…This indicates that the electronic noise is dominant in the frequency discrimination system at a frequency range above 1 Hz. The noise introduced by the RAM is quite common in a PDH system [ 33 ]. The RAM effect will ruin the stability of the locking zero-baseline, thus affecting the stability of the Sagnac frequency and ultimately the performance of our PRG.…”