All optical spatial light modulator for reconfigurable silicon photonic circuits
Reconfigurable photonic devices capable of routing the flow of light enable flexible integrated optic circuits that are not hardwired but can be externally controlled. Analogous to free space spatial light modulators, we demonstrate all optical wavefront shaping in integrated silicon on insulator photonic devices by modifying the spatial refractive index profile of the device employing ultraviolet pulsed laser excitation. Applying appropriate excitation patterns grants us full control over the optical transfer function of telecommunication wavelength light traveling through the device, thus allowing us to redefine its functionalities. As a proof of concept, we experimentally demonstrate the routing of light between the ports of a multimode interference power splitter with more than 97% total efficiency and negligible losses. Wavefront shaping in integrated photonic circuits provides a conceptually new approach toward achieving highly adaptable and field programmable photonic circuits with applications in optical testing and data communication.