Browse Prior Art Database

Coupling Light From a Fiber Optic Waveguide into a Thin Film Waveguide

IP.com Disclosure Number: IPCOM000079180D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Lean, EG: AUTHOR [+2]

Abstract

This is a coupler for optical guided waves which is electronically switchable, and wherein light traveling in a fiber-optic waveguide can be coupled into a thin-film waveguide.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 75% of the total text.

Page 1 of 2

Coupling Light From a Fiber Optic Waveguide into a Thin Film Waveguide

This is a coupler for optical guided waves which is electronically switchable, and wherein light traveling in a fiber-optic waveguide can be coupled into a thin- film waveguide.

Transparent substrate prism 10 has an index of refraction n(s). Thin-film waveguide 12 has a thickness t and index of refraction n(f), where n(f) is greater than n(s). Optical fiber 14 conducts light which is directed by lens 16 through high-reflectivity mirror 18. Light from optical fiber 14 then is introduced into prism 10 as an incident beam through antireflective coating 20, and reflected from the upper surface of prism 10 onto high-reflective mirror 22.

The incident beam is totally reflected from the upper surface of prism 10 and mirrors 18 and 22 form a high-O Fabry-Perot cavity, which sustains the light when tuned to the transmission frequencies.

Acoustic transducer 24 is located on the upper surface of prism 10. When actuated, acoustic transducer 24 propagates an acoustic wave which produces a periodic change in the index of refraction of the thin-film waveguide, which is illustrated as a ripple 26 between thin-film waveguide 12 and prism 10 having a periodicity Lambda.

When the periodic change in index of refraction occurs, there is no longer total internal reflection of the incident light beam and the light beam is coupled into thin-film waveguide 12 and travels in the direction of the arrow shown on thin fil...