Permanent light coupling arrangement and method for use with thin silicon optical waveguides

US7020364B2 · kind B2 · utility

Assignee

• SiOptical, Inc. · US

Inventors

• Margaret Ghiron · Allentown, US
• Prakash Gothoskar · Allentown, US
• Robert Keith Montgomery · Easton, US
• Vipulkumar Patel · Emmaus, US
• Soham Pathak · Allentown, US
• Kalpendu Shastri · Orefield, US
• Katherine A. Yanushefski · Emmaus, US

Key dates

• Filing date: Sep 23, 2003
• Grant date: Mar 28, 2006
• Expiry date: Nov 19, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B6/4206
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A trapezoidal shaped single-crystal silicon prism is formed and permanently attached to an SOI wafer, or any structure including a silicon optical waveguide. In order to provide efficient optical coupling, the dopant species and concentration within the silicon waveguide is chosen such that the refractive index of the silicon waveguide is slightly less than that of the prism coupler (refractive index of silicon≈3.5). An intermediate evanescent coupling layer, disposed between the waveguide and the prism coupler, comprises a refractive index less than both the prism and the waveguide. In one embodiment, the evanescent coupling layer comprises a constant thickness. In an alternative embodiment, the evanescent coupling layer may be tapered to improve coupling efficiency between the prism and the waveguide. Methods of making the coupling arrangement are also disclosed.