Wavelength multiple soliton amplification and transmission with an Er3+-doped optical fiber

Abstract

Gain characteristics of an Er³⁺ ‐doped fiber for high‐power picosecond input pulses are studied with an InGaAsP laser diode pump source at 1.46–1.48 μm. The output energy and peak power of the amplified pulses reach as high as 7.9 pJ and 792 mW for a repetition rate of 100 MHz and a pulse width of 10 ps. The gain saturation is so slow that the gain in high‐speed pulse transmission systems is determined by a steady‐state saturated gain. With the Er³⁺ ‐doped fiber amplifier, it is shown that solitons can be amplified and transmitted over a long dispersion‐shifted fiber by using the dynamic range of an N=1 soliton. Furthermore, optical solitons at wavelengths of 1.535 and 1.552 μm have been amplified and transmitted simultaneously over 30 km with an Er³⁺ ‐doped fiber repeater for the first time. The collision experiments between these different wavelength solitons is described. It is shown that there is a saturation‐induced cross talk between multichannel solitons, and the cross talk (the gain decrease) is determined by the average input power in high bit‐rate transmission systems.