Coherently coupled photonic crystal vertical cavity lasers for communication applications

Optical interconnects will have an important role for internal communication within future spacecrafts as well as infra-communication between satellite constellations. Optical sources with novel functionality, such as solid state beam steering, would have many advantages. A novel approach for creating 2-dimensional arrays of coherently coupled vertically emitting laser cavities has been demonstrated and is discussed herein. Coherent optical coupling is achieved by creating a 2×2 array of defect cavities within the top distributed Bragg reflector of a photonic crystal vertical cavity surface emitting laser. By modifying the index within the coupling regions, accomplished by varying the hole parameters in those regions, coherent coupling has been observed in the far field. Utilization of this approach may lead to extended area coherent sources with high spectral purity. Moreover, tuning the phase shift between lasers in the array would enable angular steering the far field emission pattern. Such a coherent array of lasers would allow the development of optical communication laser sources with electronic beam steering capability.