Abstract

Recently, several high speed long span transmission experiments have been reported, which treat over 10 Gb/s systems [1–4] and over 900 km long span transmission system[5], using Er³⁺-doped fiber amplifiers. For an over 10 Gb/s long span transmission system, using an ideal external modulator and a normal fiber, however, transmission length is limited to less than 50 km due to fiber dispersion[6]. For a system using a semiconductor electro-absorption modulator, residual chirping, which is induced by semiconductor refractive index variation during intensity modulation, limits the transmission length to about 20 km[7], less than that for the ideal case.

© 1990 Optical Society of America