GaAs and his coumpounds are key materials of the optoelectronics industry, at the core of electrically pumped semiconductor lasers.
In view of integrating our optomechanical disk resonators with future optoelectronics functionnalities, we have developed on-chip bus waveguides to obtain integrated optical acess to the disk resonators. The access is provided by GaAs tapered waveguides with nanoscale cross-section, which are suspended in the vicinity of the disks to allow evanescent disk/waveguide coupling. In the tapered zone, the optical guides are single-mode and follow an adiabatic profile that allows high optical transmission.
By varying the gap distance between disk and waveguide, the amount of evanescent coupling is adjusted and the important critical coupling regime can be reached, where a maximum of photons is injected in the disk whispering gallery cavity.
See our paper recently published in Applied Physics Letters :
C. Baker, C. Belacel, A. Andronico, P. Senellart, A. Lemaitre, E. Galopin, S. Ducci, G. Leo, and I. Favero. ’Critical optical coupling between a GaAs disk and a nanowaveguide suspended on the chip’. Applied Physics Letters 99, 151117 (2011).
Below, a side-view SEM picture of GaAs disk optomechanical resonators evanescently coupled to suspended GaAs nano-waveguides.
