Reconfigurable InP waveguide components using the Sb <sub>2</sub> S <sub>3</sub> phase change material
Li Lu, Sander Reniers, Yunzheng Wang, Yuqing Jiao, Robert E. Simpson
Abstract
Abstract Reconfigurable waveguide components are promising building blocks for photonic neural networks and as an optical analogue to field-programmable gate arrays. By changing the effective index of the waveguide, reconfigurable waveguide components can achieve on-chip light routing and modulation. In this paper, we design and demonstrate an Sb 2 S 3 -reconfigurable InP membrane Mach–Zehnder interferometer (MZI) on a silicon substrate. Sb 2 S 3 , which has tunable refractive index and low absorption in the near-infrared spectrum, was patterned on the InP waveguide MZIs to make an optical switch in the telecoms conventional-band. By laser induced crystallisation of the Sb 2 S 3 , it was possible to control interference in the MZI and achieve 18 dB on/off switching at 1540 nm. Laser reamorphisation and reversible switching of the Sb 2 S 3 layer resulted in damage to the waveguide structure. However, simulations show that transition metal di-chalcogenide two-dimensional crystal layers can act as efficient thermal barriers that prevent thermal damage to the waveguide during laser amorphisation. Therefore, combining Sb 2 S 3 with InP waveguides seems to be a feasible approach to achieve low-loss reprogrammable waveguide components for on-chip photonics routing and neural networks.