Figure 4: Experimental setup for detuning measurements in a hot resonator.
From: Phase steps and resonator detuning measurements in microresonator frequency combs
This setup enables the measurement of detunings between optical frequency comb modes and their respective microresonator modes during the comb generation. (a) An external cavity diode laser (ECDL) seeds the resonator and generates an optical frequency comb. Simultaneously, a probe ECDL is coupled into the microresonator in the backward direction and swept across one of the modes that are part of the frequency comb. (b) Oscilloscope recording of the absorption profile of the resonator mode together with the beating between probe laser and the fraction of the light in the comb mode being back-reflected in the microresonator. The time domain axis from the oscilloscope is converted to a frequency axis using the beat frequency as calibration. Amp, optical amplifier; BP, optical bandpass filter; OSA, optical spectrum analyser; Pol, polarization controller.
