Fig. 1. Single-mode yield when the π phase shift is placed at different positions of the laser cavity.

Fig. 2. (a) Schematic of the DFB laser array. (b) Schematic drawing of the grating. SCH-MQW, separate confinement hetero-structure-multi-quantum well; BG, Bragg grating; WG, waveguide; π-EPS, π equivalent phase shift.

Fig. 3. (a) Picture of the laser array chip under the microscope. (b) Cross-section SEM image of the DML. (c) SEM image of the DML gratings.

Fig. 4. Microscopic top view of the DML array chip on gold-coated AlN carrier (GCPW, ground coplanar waveguide).

Fig. 5. (a) Schematic of the PWB integration of the DML array chip and PLC chip, and (b) photo of the integrated sample (COC, chip on the carrier).

Fig. 6. Mode field dimension of the DML.

Fig. 7. Overlap between the MFD for PWB waveguides and laser with varying (a) width and (b) height.

Fig. 8. A scan of the Z coordinate values for the (a) DML and (b) PLC.

Fig. 9. 3-D plot of the PWB waveguide.

Fig. 10. (a) Microscopic top view of photonic wire bonding between the DML array and the PLC. (b) Scanning electron microscope (SEM) image of PWB waveguides and (c) SEM image of a single PWB waveguide.

Fig. 11. (a) Superimposed optical spectra of the 8-channel DML array at 100 mA and (b) power-current curves for the 8-channel DML array.

Fig. 12. Measured power from the single-mode fiber with respect to different currents for all 8 channels.

Fig. 13. Modulation response (S21) when the injected current is varied from 40 to 70 mA.

Fig. 14. Measured back-to-back 25 Gb/s eye diagrams of the transmitter at 60 mA.