Optimization of multimode graded-index fiber parameters: design considerations.

The structural design of multimode graded-index fibers is described. Minimum optical loss and wide bandwidth of a repeater section are looked upon as design goals. The outer diameter is chosen as small as possible from an economic point of view while maintaining high quality in the transmission characteristics. The most suitably designed values for operation with a laser source in the wavelength region around 0.85 microm are o.d., 125 microm, core diam, 50 microm, and refractive-index difference, 0.015.