Interfacing multiple wavelength sources to thin optical waveguides utilizing evanescent coupling

US7058261B2 · 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 7, 2004
• Grant date: Jun 6, 2006
• Expiry date: Sep 7, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B6/34
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An arrangement for achieving and maintaining high efficiency coupling of light between a multi-wavelength optical signal and a relatively thin (e.g., sub-micron) silicon optical waveguide uses a prism coupler in association with an evanescent coupling layer. A grating structure having a period less than the wavelengths of transmission is formed in the coupling region (either formed in the silicon waveguide, evanescent coupling layer, prism coupler, or any combination thereof) so as to increase the effective refractive index “seen” by the multi-wavelength optical signal in the area where the beam exiting/entering the prism coupler intercepts the waveguide surface (referred to as the “prism coupling surface”). The period and/or duty cycle of the grating can be controlled to modify the effective refractive index profile in the direction away from the coupling region so as to reduce the effective refractive index from the relatively high value useful in multi-wavelength coupling to the lower value associated with maintaining confinement of the optical signals within the surface waveguide structure, thus reducing reflections along the transition region.