Browse Prior Art Database

Full-Wafer Testing of Laser Diodes

IP.com Disclosure Number: IPCOM000037166D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Voegeli, O: AUTHOR

Abstract

This article describes an arrangement for "on-wafer" testing of the light beam characteristics of laser diodes. A sensor, sensitive to the radiation emitted by the laser, receives not only that segment of the laser beam reaching the sensor directly but also a substantial portion of a beam segment which strikes an etched surface, where it is reflected to reach the sensor indirectly.

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Full-Wafer Testing of Laser Diodes

This article describes an arrangement for "on-wafer" testing of the light beam characteristics of laser diodes. A sensor, sensitive to the radiation emitted by the laser, receives not only that segment of the laser beam reaching the sensor directly but also a substantial portion of a beam segment which strikes an etched surface, where it is reflected to reach the sensor indirectly.

In the figure, the essential elements of the test arrangement are schematically shown. The laser to be tested is designated 1. It is one of, normally, many devices grown on and still remaining on the unparted wafer. The mirror facet 2 of the laser, having been obtained by etching a trench 3 of a width L, corresponds to one of the trench walls. The other, far-end wall 4 forms a facet of a neighboring structure 5. The bottom 6 of the trench provides a highly reflective horizontal surface.

In the drawing, the laser beam is divided into segments D, R and A. Segment D exits the laser site unobstructed over the far-end trench wall 4, R exits after reflection at the trench bottom, and the light of the in between segment A is blocked by wall 4. Segments D and R, fold ed over each other, constitute the output from the laser site on the wafer. It is intersected by a photo-electric sensor 7 arranged at some distance from the wafer. Typically, this sensor is a sensing array capable of measuring the spatial distribution of the light intensity.

The disclosed arrang...