Modelocked Tm-doped Fiber Laser Using Multimode Interference Saturable
Absorber in Reflection Mode
Abstract
We present a reflection mode saturable absorber based on nonlinear
multimode interference in a graded index multimode fiber. The saturable
absorber provides a modulation depth of 12% at a low saturation
intensity of 18.5 MW/cm2. The all-fiber structure and
reflection mode design of this saturable absorber makes it an ideal
device for the fabrication of fiber lasers with linear resonant cavity.
When inserted in a linear laser cavity comprising a thulium doped fiber
as the gain medium, the saturable absorber triggers modelocked noise
like pulses with a center wavelength of 1905 nm and spectral width of
11.2 nm.