Nonvolatile and ultra-low-loss reconfigurable mode (De)multiplexer/switch using triple-waveguide coupler with Ge2Sb2Se4Te1 phase change material

Abstract

Mode-division multiplexing (MDM) is a promising approach to dramatically enhance the transmission capacity. A reconfigurable mode (De)multiplexer/switch (RMDS) is a key component for the flexible mode routing in the MDM network. A nonvolatile and ultra-low-loss RMDS is proposed via a triple-silicon-waveguide directional coupler with the Ge2Sb2Se4Te1 (GSST) phase change material (PCM). The nonvolatile property of GSST makes it attractive to reduce the switching power-consumption. Benefiting from the low loss of the GSST-PCM at both amorphous and crystalline states, an RMDS with an ultra-low loss and a high extinction-ratio can be realized. The proposed RMDS is optimally designed by using the full-vectorial finite element method and 3D full-vectorial finite difference time domain method. The numerically simulated results show that a compact RMDS is with the extinction ratios of 18.98 dB and 22.18 dB, ultra-low insertion losses of 0.10 dB and 0.68 dB for the “OFF” and “ON” states, respectively at the operating wavelength of 1550 nm. An ultra-wide bandwidth of 100 nm is achieved for both the “OFF” and “ON” states.

Design for quality: reconfigurable flat optics based on active metasurfaces

“…Moreover, the small switching thickness of GST (bound by the heat dissipation rate during melt-quenching to < 100 nm [182]) limits field overlap with the active O-PCM medium and further constrains the attainable phase-tuning efficiency. A new O-PCM Ge 2 Sb 2 Se 4 Te 1 (GSST) with broadband low optical loss in both phases and large switching volume has been developed to overcome these limitations [209][210][211][212][213][214][215]. As another example, the diminished optical contrast of GST in the visible spectrum has motivated the investigation of Sb 2 S 3 as an alternative O-PCM suitable for active photonics in the visible regime [216,217].…”

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.…”

Silicon Mode-Selective Switch via Horizontal Metal-Oxide-Semiconductor Capacitor Incorporated With ENZ-ITO

“…Recently, a few approaches have been reported to build a silicon MSS for reconfigurable MDM networks, including the micro-ring resonators (MRRs) 13 , Mach–Zehnder interferometers (MZIs) 14–16 , multimode interference (MMI) couplers 17,18 , and triple-waveguide couplers (TWCs) 19–21 . Stern et al .…”

“…In order to increase the light-matter-interaction (LMI) inside the silicon switch, the TWC based configurations incorporated with phase-change materials (PCMs) and transparent conducting oxides (TCOs), including Ge 2 Sb 2 Te 5 (GST) 26 , Ge 2 Sb 2 Se 4 Te 1 (GSST) 19 , indium-tin-oxide (ITO) 20 , have been emerging as a promising approach to achieve an ultra-compact, broadband, and low-loss MSS. A nonvolatile and ultra-low-loss reconfigurable mode (De)MUX/switch has been reported based on a silicon TWC with the GSST-PCM 19 , which can achieve a compact coupling length of only 29.3 μm, a broad bandwidth covering S + C + L band, ultra-low ILs of 0.10 and 0.68 dB, and high mode ERs of 18.98 and 22.18 dB at “OFF” and “ON” states, respectively. Benefitting from the unique property of the epsilon-near-zero (ENZ) effect of the ITO-TCO, a reconfigurable mode (De)MUX/switch was numerically proposed by using a silicon TWC incorporated with a vertical metal-oxide-semiconductor (MOS) capacitor and an ITO layer 20 .…”