Design of phase change Ge2Sb2Te5 based on-off electro-optic switch

Nikhil Dhingra; Junchao Song; Souvik Ghosh; Linjie Zhou; B. M. A. Rahman

doi:10.1117/12.2287218

22 February 2018 Design of phase change Ge₂Sb₂Te₅ based on-off electro-optic switch

Nikhil Dhingra, Junchao Song, Souvik Ghosh, Linjie Zhou, B. M. A. Rahman

Proceedings Volume 10537, Silicon Photonics XIII; 105370Z (2018) https://doi.org/10.1117/12.2287218
Event: SPIE OPTO, 2018, San Francisco, California, United States

Abstract

Design of electro-optic ON-OFF switches based on well-known phase change material Ge₂Sb₂Te₅ (GST) is presented. The electro-optic switch is achieved by implementing by co-directional coupling between a 220 nm thick silicon nanowire and a silicon waveguide topped with ITO-GST-ITO layers at the 1.55μm wavelength. By introducing the electric field via the ITO electrodes, the GST layer can be changed between the amorphous and crystalline states. As the modal loss in the crystalline state is much higher than the amorphous state, through a rigorous modal analysis of the coupled silicon nanowire and GST waveguide by using the finite element method, the optimal ITO spacing is obtained at 75nm which is less sensitive to device parameter variations and thus offering better tolerances. The GST thickness is also optimized for the phase matching point at 25 nm in order to efficiently transfer power from silicon nanowire to GST waveguide to attain the OFF state. Once the device is phase matched in crystalline state, the power in the amorphous state will pass with very little interaction with the GST waveguide resulting in an ON state. The Eigenmode Expansion Method of Fimmprop is used as a junction analysis approach to calculate the optical power coupling efficiencies to the output silicon nanowire. The extinction ratio of the electro-optic switch and insertion loss in ON state at phase matching can be obtained as a function of the device length. A compact 1.75 μm long device shows a high extinction ratio of 22 dB with an insertion loss of only 0.56 dB.

Conference Presentation

Citation Download Citation

Nikhil Dhingra, Junchao Song, Souvik Ghosh, Linjie Zhou, and B. M. A. Rahman "Design of phase change Ge₂Sb₂Te₅ based on-off electro-optic switch", Proc. SPIE 10537, Silicon Photonics XIII, 105370Z (22 February 2018); https://doi.org/10.1117/12.2287218

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available