Transmission vs Transverse Offset for Parabolic-Profile Fiber Splices With Unequal Core Diameters

Accurate transverse alignment is difficult to obtain in fiber optic splices primarily due to the small size of optical fibers. Many splicing techniques1-2-3 use grooves or channels and are dependent on fiber outer diameter (OD) for transverse alignment. Experience thus far indicates that OD variations as small as ±1 percent can be achieved on a single long fiber; however, fiber-to-fiber variations for fibers drawn at different times may be considerably greater. Small fluctuations in core-diameter-to-OD ratios are also expected. When the receiving fiber core is smaller than the transmitting fiber core, a loss occurs even with perfect transverse axial alignment. Thiel 4 and Henderson 5 have reported transmission vs offset for equalcore-diameter, step-profile fiber splices and Pugh 6 has considered corediameter ratios less than one (receiving fiber smaller than transmitting fiber) for step-profile fiber splices. Calculated values for transmission vs offset for equal-core-diameter, parabolic-profile fiber splices have been obtained earlier by the author.7 917