Observation of the trapping of an optical soliton by adiabatic gain narrowing and its escape

Trapping of femtosecond optical solitons has been observed for the first time in an erbium-doped fiber amplifier operating at 1.55 m. The pulse width of the trapped soliton is adiabatically narrowed by the moderate optical gain. By further increasing the gain, the trap is broken and the carrier wavelength of the soliton starts to move toward longer wavelengths by the soliton self-frequency shift.