Bidirectional Mode-locked Soliton Fiber Laser in 2μm Using CNT Saturable Absorber

We demonstrate for the first time, to the best of our knowledge, the design and operation of a novel bidirectional passively mode-locked ring laser worked in 2 µm using a carbon nanotube saturable absorber. A thulium-doped fiber was chosen as the active element in a ring cavity arrangement. The laser generates two stable picosecond pulse trains in opposite directions, each with an individual fundamental repetition rate around 20 MHz. We believe this device will have potential for the application of dual-comb.