Measuring cutoff wavelength of HE21, TE01, and TM01 modes: a novel method using single-polarization launching.
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 microm is attained with the method.
Kato
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Y
NTT Ibaraki Electrical Communication Laboratory, Tokai, Ibaraki-ken 319-11, Japan.
Miyauchi
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M