Fig. 1. (a) Optical microscope picture of the DBR-MLLD laser array, (b) the epitaxial laser wafer structure, (c) scanning electron microscope (SEM) picture of the BJR, (d) gratings, and (e) the access waveguides of the MMI.

Fig. 2. (a) DBR-MLLD L-I characteristics of the four channels from the MMI output, (b) the DBR-MLLD L-I characteristics of the four channels from the SA output, (c) the L-I characteristics of a typical channel with different bias voltages of the SA. (d)–(f) Measured results when IGain=163mA, with the other section floating: (d) optical spectral width fit, (e) RF spectral width fit, and (f) autocorrelation trace fit.

Fig. 3. Typical channel lasing characteristics of the DBR-MLLD biased at different conditions. (a1)–(d1) measured optical spectra, (a2)–(d2) measured RF power spectra, (a3)–(d3) measured autocorrelation traces. (a) VSA=−0.3V, IGain=111mA, IDBR=11.0mA; (b) VSA=0V, IGain=193mA, IDBR=9.0mA; (c) VSA=−0.4V, IGain=173mA, IDBR=3.3mA; (d) VSA=0V, IGain=163mA, IDBR=0mA.

Fig. 4. Typical channel characteristics: (a) emission peak wavelength (WP), (b) pulse repetition frequency (F_r), (c) pulse width, and (d) TBP versus IDBR for IGain=164.1, 182.6 mA while all other sections are left floating.

Fig. 5. (a) Superposition of the four-channel optical spectra, (d) superposition of the four-channel RF spectra, and (c) the autocorrelation trace of the four channels.