Flexible metal grating based optical fiber probe for photonic integrated circuits

An optical probe for photonic integrated circuits is proposed and demonstrated. The device is based on a single-mode fiber containing a subwavelength period metal grating on the facet. When approaching an integrated waveguide, light can be efficiently coupled between probe and waveguide without the need for integrated coupling structures, paving the way for wafer-scale circuit testing. A nanoimprint-and-transfer process were developed for fabricating this probe in a single step. We report 15% coupling efficiency between a gold grating fiber probe and a 220 nmx3 mu m silicon-on-insulator waveguide and demonstrate testing of an integrated microring resonator using two probes.