Precision threshold current measurement for semiconductor lasers based on relaxation oscillation frequency

D. M. Kane*, Joshua P. Toomey

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)
58 Downloads (Pure)


The soft turn-ON of semiconductor lasers leads to uncertainty in defining and measuring the laser threshold injection current, Ith. Previously, practical calculation algorithms have been developed to achieve high-accuracy measurement of a clearly defined and reproducible quantity which is called Ith. We demonstrate a new and higher accuracy measurement of Ith using the dependency of the relaxation oscillation frequency on injection current, as compared to the existing standardized approaches. Further, if it is accepted that relaxation oscillations do not occur below laser threshold, this may be regarded as a more fundamentally based definition and measurement method to determine the laser threshold injection current in a semiconductor laser. The method may also be applicable to other types of lasers.

Original languageEnglish
Pages (from-to)2949-2952
Number of pages4
JournalJournal of Lightwave Technology
Issue number15
Publication statusPublished - 1 Aug 2009

Bibliographical note

Copyright 2009 IEEE. Reprinted from Journal of lightwave technology, Volume 27, Issue 15, 2949-2952. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Macquarie University’s products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.


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