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Measuring the Coupling Efficiency of a Laser Receptacle

IP.com Disclosure Number: IPCOM000035324D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Block, TR: AUTHOR [+3]

Abstract

A laser receptacle assembly used as a source in a fiber-optic communication system is comprised of a GaA1As or InGaAsP laser diode, a coupling lens, and a housing with an integral fiber-optic connector. The coupling efficiency of such a laser receptacle is the numeric ratio of the power launched into the core of the optical fiber to the total power emitted from the front facet of the laser, expressed as a percentage.

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Measuring the Coupling Efficiency of a Laser Receptacle

A laser receptacle assembly used as a source in a fiber-optic communication system is comprised of a GaA1As or InGaAsP laser diode, a coupling lens, and a housing with an integral fiber-optic connector. The coupling efficiency of such a laser receptacle is the numeric ratio of the power launched into the core of the optical fiber to the total power emitted from the front facet of the laser, expressed as a percentage.

The coupling efficiency is the most important parameter of a laser receptacle as it governs the amount of optical power launched into the fiber. Parameters such as link length, receiver sensitivity, number of splices or connectors, and allowable attenuation of the fiber cable depend on this parameter. In addition, the reliability of the laser device is inversely proportional to its operating power level. Therefore, the coupling efficiency must be determined in order to know the power level of the laser device and, hence, estimate the link reliability level.

The conventional method used to measure the coupling efficiency is to compute the ratio of the slopes of the power versus. current (PI) curves of the completed receptacle package 3 (coupled power differential efficiency), and the laser device 1 (laser external differential efficiency) before it is installed in the package. Both of these slopes are to be measured in the lasing region. The major problem with this technique is the requirement that the laser's PI characteristics be known before installation in the receptacle. Additional error may be caused by the different thermal environment between measurements made on the laser itself and when it is installed in the receptacle assembly.

An alternative tech...