| 摘要 |
PURPOSE: To obtain a two-wavelength channel optical fiber fusion-spliced coupler having a low inter-channel cross coupling by providing the coupler with a specified normalized frequency. CONSTITUTION: The coupler is provided with two optical fibers A, B respectively including cores and clads and mutually deposited on a narrow tapered waist part 5, two channels consists of the 1st channel with wavelengthλ1 and the 2nd channel with wavelengthλ2 and the coupler has specific wavelengthλ0 having relationλ1 <λ0 <λ2 so that connection is generated at the wavelengthλ2 and is not generated at the wavelengthλ1 . Whenαis the core radius of the optical fiber,η1 is the refractive index of the core andη2 is the refractive index of the clad, regulated frequency V is defined by the shown equation at the wavelengthλof the whole local core radius through connection structure. On the waist part of which radius is minimum in the connection structure, the specific wavelengthλ0 is set up so that the regulated frequency V is >1 and is approximated to 1.
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