Development of cleanliness specifications for single-mode connectors with 1.25 and 2.5 mm ferrules

Abstract

Contaminated optical connectors result in degradation of optical performance, functional failures, and increased deployment costs. Currently there is no widely accepted cleanliness standard based on a systematic study of the impact of cleanliness on the optical performance of fiber optic connectors. This paper summarizes the latest research of iNEMI (International Electronics Manufacturing Initiative) on development of cleanliness specification for fiber optics connectors. This research is used as a baseline for the development of IPC-8497-1 "Cleaning Methods and Contamination Assessment of Optical Assembly" standard. It compares the influence of Arizona road dust particles on the optical performance of 2.5 mm ferrules, (SC and FC), and 1.25 mm ferrules, (LC and MU) type connectors. The team measured the Insertion Loss (IL), Return Loss (RL), and the geometric parameters for both clean and contaminated connectors. Fiberscope images of the connectors before and after each mating operation were also recorded. Correlations in the changes in optical performance were analyzed as a function of the level, size, and location of the contamination. The IL and RL data were analyzed using statistical methods and images were analyzed using automated software. The particle number, size and occluded area were identified as critical factors on optical signal performance. Based on the experimental results and statistical analysis, the iNEMI team has developed a proposal for an inspection criteria matrix for 1.25 mm ferrule and 2.5 mm SM UPC connectors. The iNEMI team continues to work with IEC Working Group 6, the TIA and the IPC on universally accepted industry standards for cleanliness of fiber optics connectors. The acceptance of an industry standard for single-mode (SM) connectors will result in significant cost savings to the fiber optics industry due to the elimination of insufficient cleaning , over-cleaning, and/or the reduction of contaminated non-conforming material.JThB85.pdf 1. Introduction Contaminated optical connectors result in degradation of optical performance, which can be quantified by return loss (RL) and insertion loss (IL); functional failures; and increased deployment costs. Fiber optic connector end-face cleaning is recognized as a necessity for optimal signal performance. Currently, there is no widely accepted cleanliness standard based on a systematic study of fiber optic connectors. This potentially results in unnecessary cleaning being done even though it may not impact signal performance. Our previous research [1,2] shows that contamination impacts signal performance by blocking the core and impeding light transmission, as well as, by preventing direct physical contact creating an air gap between the two connector end-faces. If an air gap exists, optical performance will be impacted due to the change in transmission medium. As contaminated connectors are mated and demated, contamination can be redistributed around the connectors' end-face and block the fiber core. This presents a risk of signal perfo...

Improving Data Transmission in Fiber Optics by Detecting Scratches on the Fiber End Face

“…As the information focus on the fiber centre is to transmit, the standards for the end face quality of a polished fiber optic connector varies according to the region in the fiber. International Electrotechnical Commission (IEC) established standards for setting requirements for allowable surface anomalies, such as scratches and defects, which may affect optical performance [4]. Therefore, analysis of the distribution of the defects in the fiber circle can support the judgement for the quality of fiber connector.…”

“…Intensity curve or R-power curve is an important factor to inspect how the scratches and pits contaminate the optical fiber connector [4]. When the light passes through an optical fiber, the information concentrates in the centre area and that make the optical fibers center area more important than other places.…”

“…face [4]. More specifically, they justify the interdependency of the IL to the defect sizes and introduce the Gaussian Weighted Percent Occluded Area (GWPOA) to the intensity distribution of the basic fiber mode.…”