Design and Fabrication of Highly-Dense Optical Components for In-Service Fiber Testing and Monitoring in Subscriber Loops

Taisuke OGUCHI  Norio TAKATO  Hiroaki HANAFUSA  Nobuo TOMITA  Yoshitaka ENOMOTO  Naoki NAKAO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.1   pp.123-129
Publication Date: 1997/01/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Devices, Packaging Technology, and Subsystems for the Optical Access Network)
Category: 
Keyword: 
optical fiber,  testing and monitoring,  optical branch module,  planar lightwave circuit,  interference filter,  

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Summary: 
This paper describes the design and performance of optical components for in-service fiber testing and monitoring in optical subscriber loops. As the number of test fibers increases, compact and cost-effective components are becoming more important. To meet this need, we have developed a highly-dense hybrid structure for optical couplers and filters, which both play key roles in testing systems. It was realized by utilizing a polyimide-base thin film filter and a waveguide-type wavelength insensitive coupler. This component operates by combining a signal and a test light with a ratio of 80/20% and isolating the test light with a value of 50 dB. The experimental samples were successfully fabricated with an excess loss of 1 dB, a return loss of 40 dB, a plolarization dependent loss (PDL) of 0.3 dB, and good environmental and mechanical stability. We successfully applied the samples to an optical branch module (OBM), and achieved a component density twice that of a conventional module. The optical characteristics of the OBM met our target values. The results we obtained for termination cords incorporating the polyimide-base filter were also satisfactory.