Over 100 mW O-Band Multi-Wavelength DFB Laser Array for Optical I/O Technology

We propose and experimentally demonstrate an O-band multi-wavelength high-power DFB laser array for optical I/O technology. The proposed DFB laser array operates with 400-GHz wavelength spacing, which meets the CW-WDM MSA specifications. The reconstruction equivalent chirp technology is used to precisely control the grating phase and introduce the equivalent
$\pi $
phaseshift in the laser cavity. The AR and HR films are coated on the front and rear facets to increase the output power. The equivalent
$\pi $
phaseshift is placed near the HR film facet to improve the single longitudinal mode yield. The optical spectra were measured at a bias current of 150 mA, with the wavelength deviations of below 1.958 GHz, and the SMSRs of above 55 dB. Statistical analysis shows 94.8% of SMSRs are above 40 dB, and 90.0% of the wavelength spacings deviate from the designed value within ±12.5%. The laser output power is over 100 mW at the bias current of above 370 mA. The far-field divergence angle of the laser was measured to be
$25.5^{\circ } \times 29.9^{\circ }$
and the measured Lorentzian linewidth is 1.68 MHz at the bias current of 150 mA. The proposed O-band multi-wavelength DFB laser array shows uniform wavelength spacing, high output power, and good single longitudinal mode stability, which is promising to be used as the multiple wavelength laser source in the optical I/O technology.