Fig. 1. Schematic process flow for the integration of GaAs QD active devices on a SiPh platform.

Fig. 2. (a) Optical microscope images of the fabricated GaAs QD device array on the source wafer; (b) micro-transfer printed GaAs QD-on-Si SOAs on the SiPh chip; (c) cross-sectional SEM image of the taper region.

Fig. 3. (a) Top-view schematic of the GaAs QD devices after transfer printing onto the SiPh platform; (b) cross-sectional schematic of the GaAs QD-on-Si devices along the y-direction; (c) cross-sectional schematic of the QD devices on Bragg grating along the x-direction; (d) optical mode field distribution during coupling through the taper structure; (e) coupling efficiency (|S21|2) of the taper as a function of misalignment.

Fig. 4. (a) Schematic of the SiPh circuit for the widely tunable laser; (b) microscope image of the fully fabricated tunable laser on the SiPh chip.

Fig. 5. (a) Current-voltage (IV) characteristics and differential resistance of the GaAs QD-on-Si SOA at various temperatures; (b) on-chip gain spectrum of the GaAs QD-on-Si SOA as a function of wavelength at different temperatures, with the inset showing single GC loss versus wavelength and temperature; (c) on-chip output power versus waveguide (WG)-coupled input power at different bias currents; (d) on-chip gain as a function of WG-coupled input power for various bias currents.

Fig. 6. (a) Current-voltage (IV) characteristics and WG-coupled output power of the GaAs QD-on-Si DFB laser at various temperatures; (b) optical spectra of the GaAs QD-on-Si DFB laser at different drive currents; (c) frequency noise spectrum of the GaAs QD-on-Si DFB laser at various drive currents, indicating linewidth values from 2.05 MHz to 803.6 kHz.

Fig. 7. (a) Schematic diagram of the setup used for measuring the RIN of the QD-on-Si DFB lasers; (b) measured RIN spectra of the DFB laser at a constant temperature of 20°C under varying drive currents; (c) measured RIN spectra at a fixed drive current of 220 mA at different temperatures.

Fig. 8. (a) Schematic diagram of the experimental setup used for high-speed transmission testing of the GaAs QD-on-Si DFB laser; (b) bit error rate as a function of received optical power at a 30 Gbps rate; the inset shows eye diagrams corresponding to different received powers.

Fig. 9. (a) IV characteristics and WG-coupled output power of the GaAs QD-on-Si widely tunable laser with the resonant wavelength tuned to 1295.8 nm; (b) optical spectrum of the tunable laser.

Fig. 10. Measured RIN spectra of the DFB lasers with different feedback levels into the lasers driven at 230 mA (the inset is the setup for measuring the laser RIN with optical feedback).

Fig. 11. (a) BER versus the received power with and without optical feedback; (b) BER versus different optical feedback levels; the inset shows eye diagrams corresponding to varying feedback levels.