<title>Measurement of mode field diameter and fiber bending loss</title>

Abstract

This paper describes the variable aperture measurement technique for Mode Field Diameter (MFD) in 1300 nm optimized single-mode fiber. Measurement of macrobending induced loss correlates well with theory for both depressed and matched clad singlemode fiber designs. No significant difference in bending loss is found between depressed and matched clad fibers with the same MFD. For bending radii of 8 mm or smaller, the larger MFD fiber yields significantly high bending loss (>1 dB/cm). The bending loss is negligible for bending radii greater than 14 mm. For datacom applications, it is desirable to select small MFD to avoid excess bending loss.