2021/06/02 by Ting Yu Teo, Milos Krbal, Teo, Ting Yu +9
Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Optics (physics.optics) #physics.app-ph #physics.optics
paper · pdf · doi:10.48550/arxiv.2106.01169
We have added/ changed: (a) the title of this work (b) new Sb$_2$Se$_3$ and Sb$_2$S$_3$ ellipsometry measurements to strengthen our arguments in this work. The n and k values for Sb$_2$Se$_3$ was previously cited from literature. (c) fixed the PCM waveguide and PCM dimensions to ensure fair comparison across the four directional coupler performance
arxiv created 2021/11/05 · arxiv updated 2021/11/08
The unique optical properties of phase change materials (PCMs) can be exploited to develop efficient reconfigurable photonic devices. Here, we design, model, and compare the performance of programmable 1X2 optical couplers based on: Ge2Sb2Te5, Ge2Sb2Se4Te1, Sb2Se3, and Sb2S3 PCMs. Once programmed, these devices are passive, which can reduce the overall energy consumed compared to thermo-optic or electro-optic reconfigurable devices. Of all the PCMs studied, our ellipsometry refractive index measurements show that Sb2S3 has the lowest absorption in the telecommunications wavelength band. Moreover, Sb2S3-based couplers show the best overall performance, with the lowest insertion losses in both the amorphous and crystalline states. We show that by growth crystallization tuning at least four different coupling ratios can be reliably programmed into the Sb2S3 directional couplers. We used this effect to design a 2-bit tuneable Sb2S3 directional coupler with a dynamic range close to 32 dB. The bit-depth of the coupler appears to be limited by the crystallization stochasticity.