Polymer waveguide thermo-optical switch with loss compensation based on NaYF₄: 18% Yb³⁺, 2% Er³⁺ nanocrystals

A polymer waveguide thermo-optical switch with loss compensation based on NaYF₄:18% Yb³⁺, 2% Er³⁺ nanocrystals, fabricated by traditional semiconductor processes, has been investigated. NaYF₄:18% Yb³⁺, 2% Er³⁺ nanocrystals were prepared by a pyrolysis method. The morphology and luminescent properties of the nanocrystals were characterized. The nanocrystals were doped into SU-8 as the core material of an optical waveguide amplifier. The size of the device was optimized for its optical and thermal fields as well as its transmission characteristics. The device was fabricated on a silica substrate by spin coating, photolithography, and wet etching. The insertion loss of the switch device is~15 dB. The rise and fall times of the device are 240 μs and 380 μs, respectively, as measured by application of a 304 Hz square wave voltage. The extinction ratio of the device is about 14 dB at an electrode-driving power of 7 mW. When the pump light power is 230 mW and the signal light power is 0.1 mW, the loss compensation of the device is 3.8 dB at a wavelength of 1530 nm. Optical devices with loss compensation have important research significance.