Multi-wavelength gain-switched Yb-doped fiber laser

Abstract

We present a technique for suppression of wavelength competition in rare-earth -doped fiber lasers and for obtaining simultaneous lasing at tens (up to several hundred) of laser lines with wavelength spacing down to 50 pm. An ytterbium -doped fiber laser is used for experimental demonstration. Spectral selection is based on a built-in Lyot filter whose length can be selected to set suitable wavelength spacing. The measured linewidth for each of the generated lines is less than 100 pm and can be as little as 20 pm. The method for mode competition suppression is based on the gain-switching technique with modulated pump. At certain modulation parameters (amplitude, duration, and repetition rate), the laser generates a stable sequence of microsecond pulses with ~1 W peak power and ~4 µJ energy consisting of many longitudinal modes.

Coupled Femtosecond Laser Assisted Doping and Fragmentation of MoO3 Nanosheets Generates Plasmonic QDs with Strong NLO Response

“…The slight fluctuation of the optical spectrum profile could be due to the mode competition of the YDFL. [ 32 ] Figure 4b shows that the pulse train with pulse repetition rate of ≈20.5 MHz (reciprocal of 49 ns) was obtained at the pump power of 160 mW, which agrees well with the fundamental frequency of the resonant laser cavity with a total cavity length of ≈10 m. Subsequently, multiple pulses with a pulse repetition rate of ≈20.5 MHz were measured by slightly increasing the pump power to 170 mW, implying typical characteristic of mode‐locked fiber laser. The single pulse could be once again obtained by decreasing the pump power to 160 mW without adjusting the PC status.…”