Fig. 1. Configuration of the transfer cavity and its chamber.

Fig. 2. Schematic diagram of the multiple wavelength frequency stabilization with the transfer cavity. DM, dichroic mirror; QWP, quarter-wave plate; HWP, half-wave plate; PBS, polarization beam splitter; HR, high-reflection mirror; PD, photodiode; PID, proportional-integral-differential servo; FEOM, fiber electro-optical phase modulator; SG, signal generator. 1062-nm USL, ULE cavity stabilized laser system at 1062 nm.

Fig. 3. PDH error signal of the transfer cavity with the phase modulated 1062-nm reference laser. Black: the error signal of one sideband when the transfer cavity is scanning. Red: when the transfer cavity is locked. Inset: the full range with carrier and two sidebands.

Fig. 4. The beat note frequency variation of two 1015-nm lasers (SL-2 and SL-3) when (a) both of them are transfer-locked on the ultra-stable laser and (b) one of them is transfer-locked on the ultra-stable laser but the other is locked on a free running temperature-controlled FP cavity. (c) The beat note signal of two 1015-nm lasers, which are transfer-locked. (d) The beat note signal of two 725-nm lasers, which are transfer-locked. The red line indicates the Lorentz fit. The RBW of the spectrum analyzer is 3 kHz.

Fig. 5. Beat note frequency (black) and temperature of TC-2 (red) without temperature-controlling over 4 hours.

Fig. 6. (a) The beat note frequency variation of SL-2 and SL-1. (b) The beat note frequency variation of SL-3 and SL-1. (c) The Gaussian-fitted curve to the statistical frequency counts of the beat note frequency variation of SL-2 and SL-1. (d) The Gaussian-fitted curve to the statistical frequency counts of the beat note frequency variation of SL-3 and SL-1.

Fig. 7. Allan deviation of the beat note frequency signal between the FMSAS-locked laser and transfer-locked lasers. The gate time is 100 ms in the frequency counter.

Fig. 8. Saturated absorption spectrum and FMSAS error signal by the transfer-locked SL-2 1015-nm laser. The step frequency is 200 kHz, and the dwell time is 500 ms.