Cutoff wavelength measurement in a fiber with improved bending loss

In this letter, we describe a novel method for evaluating the cutoff wavelength in a single-mode fiber based on far-field pattern (FFP) measurement under different launch conditions. We show that the proposed method can be applied not only to conventional fiber but also to a special fiber with superior bending loss performance. We also discuss the relationship between the FFP measurement conditions and the measurement accuracy of the proposed method.