High temperature stability in integrable quantum dot lasers with dry etched mirror facets for on-chip optical interconnects

At the present time, there is an urgent need for larger memory bandwidth inside the CPU, particularly for high end applications. As data rates increase, it is becoming increasingly more challenging to transmit signals electrically while maintaining low power consumption, low delay, and good signal integrity. A quantum dot laser, integrated with optical interconnects is an attractive candidate for such purposes. One requirement for such devices will be high quality laser facets. Cleaved facets provide an ideal mirror, but are not practical for device integration. Dry etched facets, on the other hand, have the advantages of having high throughput, with whole wafer processing possibility, allowing for accurate control of etch depth, and allowing for smooth and vertical facets. By optimizing the reactive elements used to perform the etching, the power sources, and the chamber pressure, we have obtained results nearly identical to those obtained with cleaved facets. Furthermore, to increase temperature stability, a superlattice structure, consisting of alternating pairs of wide and narrow bandgap materials, was integrated into the laser heterostructure. The superlattice, in conjunction with tunnel injection allows for both T0 and T1 -∞ between 5°C to 65°C These lasers are being integrated with tapered optical waveguides.