Feasibility study of a Ge₂Sb₂Te₅-clad silicon waveguide as a non-volatile optical on-off switch

Design, optimization, and performance evaluation of GSST clad low-loss non-volatile switches

“…It can be noted that when GSST is in crystalline state, the waveguide has a larger effective index, both in real and imaginary parts, which also suggests a larger mode loss. Although these values depend on the waveguide design, but for a comparable design both these values are lower than the GST based design [14] along with a very low modal loss for the amorphous state.…”

“…Therefore, the total insertion loss in the 'OFF' state (crystalline) exceeding 20 dB compared to the 'ON' state (amorphous). We have recently reported a GST-clad Si waveguide based optical switch design with 2.27 µm device length and a minimum insertion loss 0.359 dB and this is given in Table. 2 [14]. However, if low-loss GSST used in the EA switch design, the minimum insertion loss could be reduced to only 0.135 dB, which is 38% of the earlier GST based design and with a 4.75 µm device length shows a greater potential for low loss PICs.…”

All-Optical Synapse With Directional Coupler Structure Based on Phase Change Material

“…Silicon optoelectronics has long been the mainstream of nowadays optical neuromorphic devices for its compactness and compatibility with a traditional CMOS process, and however, silicon-based optoelectronic devices encounter their intrinsic bottleneck due to the limited refractive index tuning range in this flourishing age of artificial intelligence [14,15]. Silicon based photonic devices using GST materials with extremely large refractive index tuning range have been reported to address this issue, such as Mach-Zehnder interferometers (MZI) structures [16][17][18], micro-ring resonators [19][20][21][22], optical switches [23,24], directional couplers [25][26][27]and some other devices [28][29][30]. However, all-silicon optical synaptic devices using GST materials have a non-negligible problem of nonlinear weight update.…”

Broadband Electro-Optical Crossbar Switches Using Low-Loss Ge2Sb2Se4Te1 Phase Change Material

“…Today, O-PCMs are seen as a good alternative because they give nonvolatility and strong modulation. As a result, a number of O-PCM applications ranging from switches [2][3][4][5][6][7][8][9][10][11][12][13][14][15], to modulators [16,17], photonic memories [18][19][20], and light manipulation [21] have recently been explored. Chalcogenides and compounds in the germanium-antimony families were studied.…”

“…An examination of the prior art literature on O-PCM switches shows several recent papers [2][3][4][5][6][7][10][11][12][13] that analyze the performances of optical devices based on Ge2Sb2Te5 on the SOI platform and Ge2Sb2Se4Te1 on both silicon nitride (SiN) [8,9] and SOI platforms [14,15]. Here we propose an alternative approach based on Ge2Sb2Se4Te1 on SOI.…”