Thermo-optical switch with wavelength division multiplexing function

Flexible and compact optical switch is important for optical communications. In this Letter, a thermo-optical switch with wavelength division (de)multiplexing (WDM) function has been proposed and demonstrated experimentally. The switch is comprised of a 1 × 2 Bezier multimode interferometer (MMI) and an angled multimode interferometer (AMMI). The switch separates 1490 and 1550 nm wavelengths and realizes path reconfiguration simultaneously. The demonstrated device with a footprint of 13.63 × 0.385 mm² is built on a 2% refractive index difference silica platform. The excess loss is lower than 1.2 dB (the reference waveguide loss is larger than 5.6 dB). In the central wavelength, the cross talk is lower than -21.7 dB and the extinction ratio is larger than 21.7 dB. The 3 dB bandwidth is larger than 30.8 nm. The wavelength shift rates of central wavelength are ∼54 pm/nm in C band and ∼74.8 pm/nm in the S band with the width of the AMMI changed. The rise (10%-90%) and fall (90%-10%) times of the switch are 0.88 and 0.94 ms, respectively, with a maximum power consumption of 246.6  mW. The demonstrated switch combines WDM and router functions together. Scalability property makes it possible for a large port count number switch.