Browse Prior Art Database

Holographic Cover Plate Laser Power Monitor

IP.com Disclosure Number: IPCOM000108894D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Dickson, L: AUTHOR [+2]

Abstract

In many laser-based products, be it printer, CD player, or optical data storage devices, it is often necessary to monitor laser output power and protect the optics from contamination. A holographic cover plate laser power monitor is designed to meet both goals with the benefit that the holographic optical element (HOE) efficiency is insensitive to environment and aging.

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Holographic Cover Plate Laser Power Monitor

      In many laser-based products, be it printer, CD player, or
optical data storage devices, it is often necessary to monitor laser
output power and protect the optics from contamination.  A
holographic cover plate laser power monitor is designed to meet both
goals with the benefit that the holographic optical element (HOE)
efficiency is insensitive to environment and aging.

      As shown in Fig. 1, by proper design and construction of a
volume holographic grating sandwiched between two pieces of glass,
the cover glass can also servo as a weak beamsplitter to deflect and
trap part of the incident light and direct it to a power monitor
detector epoxied at one edge of the cover glass/HOE sandwich.  Note
that this light is not trapped within the HOE medium itself, but is,
instead, confined within the waveguide formed by the surfaces of the
two cover glasses and exits at the edge of the HOE/glass assembly.

      Disclosed anonymously.