Fig. 1. (a) Two types of MIRs; (b) two types of OCMLLD structures.

Fig. 2. Photograph of two on-chip mode-locked lasers, using MIRs, with the SA at the two different locations.

Fig. 3. Experimental setup: AC, autocorrelator; EDFA, erbium doped fiber amplifier; ESA, electrical spectrum analyzer; I, current source; Iso, optical isolator; OSA, optical spectrum analyzer; PC, polarization controller; PD, photodiode; PM, power meter; −V, reverse bias voltage.

Fig. 4. (a) Optical power versus current (L–I curve); regions are FP, Fabry–Perot; ML, mode-locked; (b) optical spectra map.

Fig. 5. Optical spectrum of the OCMLLD in the mode-lock state; central wavelength, 1558 nm; span, 30 nm; inset shows the frequency mode spacing; resolution is 0.02 nm.

Fig. 6. Electrical spectrum of the OCMLLD; center frequency, 15 GHz; span, 30 GHz; resolution bandwidth (RBW), 1 MHz; video bandwidth (VBW), 1 MHz.

Fig. 7. (a) Pulsewidth versus gain section current level at fixed VSA; (b) pulse width versus reverse absorber voltage at fixed ISOA; (c) measured optical pulse shape (blue, line marked with circles) fitted to a Gaussian lineshape (red, continuous line).