Figure 2: Intrinsic Q factor measured for the various resonator lengths.
From: Spiral resonators for on-chip laser frequency stabilization
The maximum Q factor obtained was 140 million at a length of 1.2 m. The blue curve is a theoretical prediction for the Q versus length that assumes a waveguide loss of 0.15 dB m−1. Upper left: a typical optical spectrum in blue. The sinusoidal curve is an interferometer scan that is used to calibrate the linewidth. Lower right: spectral scan in excess of one free-spectral range for the TE polarization. The black curve is the interferometer calibration trace.
