Fused single mode optical fiber couplers

摘要

A two-channel single mode fiber fused coupler 1 comprising two optical fibers A, B each with a core 2 and cladding 3, fused together at a narrow tapered waist 5. The first channel is at a wavelength of lambda 1 and the second channel is at a wavelength of lambda 2 where lambda 2 is longer than lambda 1. The coupler is fabricated to have a characteristic wavelength lambda 0 such that for wavelengths lambda 2 longer than lambda 0 coupling occurs and for wavelengths lambda 1 shorter than lambda 0 the light at lambda 1 is core guided throughout the coupler and thus does not couple across. lambda 1 may be 1.3 mu m and lambda 2 1.55 mu m or lambda 1 may be 0.8 mu m and lambda 2 1.3 mu m.