Fig. 1. SuperNova^TM multi-wavelength source architecture^[4].

Fig. 2. Schematic of (a) the DFB laser array unit, (b) the grating designed by the REC technology, and (c) the distribution of the sampling grating period along the whole cavity. π-EPS, equivalent π phase shift; P, sampling period; SCH-MQW, separate confinement heterostructure-multi-quantum well; WG, waveguide; BG, Bragg grating.

Fig. 3. Threshold gain margin of (a) conventional center π phase shift grating and (b) APS grating structure when the random phase from the HR coating facet varies from 0 to 2π.

Fig. 4. Simulation results of (a) the fundamental mode field, (b) the high-order mode field, (c) the far field of the fundamental mode, and (d) the divergence angles of the fundamental mode.

Fig. 5. (a) Schematic of a typical high-power laser diode package, (b) simulation result of heat flux distribution of p-side-up bonded structure, and (c) simulation result of heat flux distribution of flip-chip bonded structure.

Fig. 6. The simulation results of the source region temperature at the steady states of the p-side-up structure and flip-chip bonded structure chips.

Fig. 7. (a) Microscopic top view of the proposed DFB laser array, (b) SEM image of a detailed profile of the cross-section of a waveguide, and (c) schematic of the flip-chip manufacturing process and photo of flip-chip DFB laser array.

Fig. 8. (a) Microscopic top views of the p-side-up structure (left) and flip-chip (right) bonded laser array unit and (b) their cross-sectional views.

Fig. 9. Spectra and SMSRs of the (a) p-side-up and (b) flip-chip bonded structure laser array units as the temperature varies in the range of 25°C to 60°C, and (c) wavelength fitting analysis at different temperatures of p-side-up and flip-chip bonded structure laser array units.

Fig. 10. (a) Spectra of the (a) p-side-up and (b) flip-chip bonded structure laser array units as the bias current varies in the range of 50 to 250 mA, and (c) the power-current curves for the p-side-up and flip-chip bonded structure laser array units.

Fig. 11. (a) Superimposed optical spectra of the flip-chip bonded 8-channel laser array at 110 mA and (b) spectral fitting analysis.

Fig. 12. P-I-V curve of the flip-chip bonded 8-channel laser array at 25°C. The insert is the enlarged view of the P-I-V curve near the threshold current.

Fig. 13. Far-field divergence angle at a temperature of 25°C for bias current of (a) 110 mA and (b) 150 mA, respectively.

Fig. 14. Linewidths of the Lorentzian fits after spectrum analyzer measurement at bias currents of 50 to 200 mA.

Fig. 15. Measured RIN for the flip-chip bonded 8-channel laser array when the bias currents are 110 mA at 25°C, respectively.