City Research Online

Abstract

We propose the design of a nonvolatile,low-lossopticalphase shifter based on optical phase change material(O-PCM).The opticalphase change material Ge2Sb2Se4Te1(GSST), which exhibitslow lossat telecommunication wavelength1.55 μmas compared to other commonly used O-PCMs, is usedin this work as the active material. Instead of direct interaction of the waveguide mode with the O-PCM, the design utilizescouplingbetween the primary SiN strip waveguide andawaveguide formed by O-PCM, in itsamorphous state.Thephase matching in the amorphous state inhibits theinteraction of the waveguide mode withGSST in itshighly lossy crystalline state resulting in low loss operation.Due to a high differential refractive index between the two states of GSST, the design requires a very small length of the phase shifter to accumulate the desired phase difference.The overall response of the Mach-Zehnder Interferometer (MZI) configurationusing the designedphase shiftershows that the design can be used to obtain optical switching with avery small insertion loss and crosstalk over the entire C-band.

Publication Type:	Article
Additional Information:	© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Publisher Keywords:	Phase shifters, Optical crosstalk, Optical interferometry, Optical refraction, Optical variables control, Silicon compounds, Phase change materials
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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