A continuous wave suppressed, uniformly repetitive pulse train as short as 136–145 fs has been successfully generated at a wavelength of 1.55 µ m from a new type of femtosecond erbium-doped fiber laser with nonlinear polarization rotation. The 145 fs pulse was shortened to 52 fs by using soliton narrowing and high order soliton compression. Soliton narrowing was achieved by amplifying the soliton pulse with an erbium-doped fiber amplifier, and a short length of dispersion-flattened fiber was used for further compressing the soliton.
- Erbium-doped fiber
- Femtosecond pulse
- Fiber laser
- Nonlinear polarization rotation