The mode field diameter（MFD） of ITU-T G.657.A2

A3 and ITU-T G.657.153 fibers were measured under different methods to remove higher order mode to understand the higher order mode’s influence on the measured MFD results at 131（）nm.The test results show that increasing the G.657 sample fiber length to 22 meters or splicing two meters of ITU-T G.652 complaint standard single-mode lead fiber to 2 meters G.657 sample fiber and applying two 80 mm turns on the lead fiber can both obtain accurate measurements for G.657. A including A3 or G.657.B fiber MFD at 1310nm.The measured MFD at 13l0nm will he lower than the actual MFD since other higher order mode removal methods been used by introducing more than one loops with smaller radius on the 2 meters G.657 fiber sample is not always a sufficient higher order mode filter

especially to the good bending-loss insensitive G.657.A including A3 or G.657.B fiber withλc≥1310nm.To avoid the higher order mode influence

a 22 meters G.657 fiber sample or splicing 2 meters of ITU-T G.652 complaint standard single-mode lead fiber to a 2 meter G.657 sample fiber and applying two 80 mm turns on the lead fiber are recommended to measure G.657 fiber MFD at 1310nm.