A new method for measuring the cutoff wavelength of HE21, TE01, and TM01 modes in single-mode fibers is reported. The method is based on the difference in polarization between the HE11 and second-order modes launched in the offset condition. A single-polarization fiber several meters in length is used as a launching fiber to eliminate cladding mode disturbance and realize linear polarization launching into a test fiber. Good agreement between theoretical and measured cutoff wavelengths for fibers with various refractive-index profiles confirms the high accuracy of the method. A resolution of ±0.005 µm is attained with the method.
© 1985 Optical Society of America.
Yasuyuki Kato and Mitsuru Miyauchi, "Measuring cutoff wavelength of HE21, TE01, and TM01, modes: a novel method using single-polarization launching," Appl. Opt. 24, 2351-2354 (1985)