Fusion splicing erbium doped fiber (EDF) to other single mode fibers has become more critical as the required overall insertion loss for erbium doped fiber amplifiers (EDFA) has significantly decreased in the last few years. In this paper, we describe and discuss an approach to develop a low loss splice method for fusion splicing high numerical aperture (NA) 980/1600 wavelength-division-multiplexing (WDM) coupler fiber and EDF. The results indicate that the fiber end preparation before the fusion is especially critical for obtaining a low loss splice for the fiber pair.
A 980/1600 Wavelength Division Multiplexing (WDM) fiber coupler is a critical component of an L-band (1580 nm to 1620 nm wavelength region) Erbium Doped Fiber Amplifier (EDFA), and the application in the L-band requires low optical loss at 980 nm and 1600 nm for the single mode fiber used in making the coupler. Common single mode fiber, designed for use at 980 nm, would usually have a significantly higher optical loss at these wavelengths. Therefore, a new design may be required. In this paper, we describe our work in fiber design to meet the new requirements and discuss relevant issues, especially fiber attenuation and bend loss performance.