Figure 2

The cavity output signal and post-cavity signal when tuning the applied laser current with a sawtooth signal at 20 Hz. (a) Even and odd modes as well as threshold current lowering effect on optical feedback. (b) A magnification of the modes between 0.02 s to 0.03 s. Locking time, estimated by the FWHM, is 510 µs. The time between modes is 1250 µs.