Efficient phase shifter with inkjet-printed liquid crystal on an integrated photonics platform

In large interferometric circuits on SOI-platforms a high number of phase tuners is required to control the flow of light. Furthermore, reconfigurable circuits rely on the control of the phase in each arm of a balanced Mach-Zehnder interferometer (MZI) to create a 2×2 coupler with full control on the coupling and phase difference between the output ports [1]. Consequently, such circuits require a large amount of phase shifters densely integrated on the chip surface. To enable this, each phase shifter should have a 2π tuning range at a low voltage to ease to co-integration with the driver electronics. Furthermore, as the mesh size increases the insertion loss (IL) should be limited to avoid signal degradation. Since these devices are densely integrated in such circuits, both the footprint and optical length should be as small as possible while avoiding cross-talk between neighbouring devices.