Effect of Surface Roughness Profiles on Optical Characteristics of Plastic Split Sleeves for Single-Mode Fiber-Optic Connectors

Yoshito SHUTO  Hirotsugu SATO  Shuichi YANAGI  Masayoshi OHNO  Shin SUMIDA  Shunichi TOHNO  

IEICE TRANSACTIONS on Electronics   Vol.E83-C    No.10    pp.1657-1662
Publication Date: 2000/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Optoelectronics
optical connector,  injection molding,  split alignment sleeve,  epoxy resin,  

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We successfully fabricated split alignment sleeves for single-mode operation with the injection-molding technique using both thermosetting epoxy resin and thermoplastic polyetherimide (PEI) resin. The relationship between the surface smoothness and the connection-loss characteristics of these injection-molded plastic sleeves was investigated. We made two-dimensional contour maps of the outer and inner surfaces of the plastic sleeves using the measured surface roughness. There were many contour lines on both the outer and inner surfaces of the PEI sleeve. In contrast, the epoxy sleeves had very smooth surface profiles. An offset Δr was estimated by using the inner-surface roughness data of the sleeve-ferrule contact regions. The connection loss of the sleeve increased as the Δr value increased. The measured losses agree fairly well with the theoretical losses estimated by using the Δr values. The PEI sleeves exhibited large Δr values, and one-third of them had large connection losses of > 0.5 dB. In contrast, the epoxy sleeves had very small Δr values of < 0.6 µm, and exhibited an average loss of < 0.1 dB.