Abstract

Step-index multimode fiber (SI-MMF) has been used in many fields and industries, including the automotive and railroad industries. Although the modal power distribution (MPD) of SI-MMF greatly influences its transmission characteristics, we rarely discuss the MPD dependency of systems and components composed of the fiber because there is no measurement metric to define MPD. Under the circumstances, encircled angular flux (EAF), which is a new metric for defining the MPD in SI-MMF, has been developed. Here, the EAF measurement method and a measurement apparatus for fθ imaging, which is the standardized EAF measurement method of the International Electrotechnical Commission, are reported. Using the apparatus, we analyzed the MPD in a hard polymer cladding fiber. We examined the measurement tolerances of the apparatus, which has sufficient tolerances of ±0.5 mm or more in all axes within a variation of ±15% at the EAF of 95%. We also investigated the measurement reproducibility of the apparatus and showed that the apparatus has sufficient reproducibility as indicated by the standard deviation of 0.008° based on repeated measurements. We showed that insertion loss was caused by higher mode radiation at connections.

© 2016 IEEE

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