Wideband spectral compression of wavelength-tunable ultrashort soliton pulse using comb-profile fiber.

We demonstrated spectral compression of ultrashort soliton pulses in a wide wavelength region based on an adiabatic soliton spectral compression technique using a comb-profile fiber. The comb-profile fiber was carefully designed using numerical analysis and fabricated using a conventional single-mode fiber and a dispersion-shifted fiber. The spectral width of a 200 fs soliton pulse was compressed from 12 to 15 nm to 0.54-0.71 nm in the wavelength region 1620-1850 nm, giving a spectral compression factor of up to 19.8-25.9. Owing to the soliton effect, the side lobe level was suppressed to -19.2 to -9.7 dB.