Elastomer-based tunable virtually imaged phased array for reconfigurable optical interconnects

Virtually imaged phased arrays (VIPA) offer high dispersion compared to conventional gratings and have been proposed as buildings blocks for several photonic devices, including wavelength multipliers, chromatic dispersion compensators, waveform generators and pulse shapers. We introduce an elastomer-based tunable VIPA, providing an additional degree of freedom for these devices. In particular, we investigate its capability to implement reconfigurable optical interconnects. In a wavelength demultiplexing setup it allows for both compensation of misalignment as well as reconfiguration of a source wavelength to a target channel. It consists of an elastomer layer sandwiched between two structured silver coatings on a glass substrate forming the resonator cavity. Using Joule heating of the top silver layer a thermal expansion and a thermo-optic effect of the elastomer cavity is induced allowing for tuning the effective optical resonator cavity. We report a tuning span of one free angular range by a temperature increase of less than 10K induced by a power change in the low mW regime. Both resonance quality and tunability of the device are investigated.