Dual-Wavelength, Bidirectional Single-Wall Carbon Nanotube Mode-Locked Fiber Laser

A fiber ring laser with a carbon nanotube mode-locker that allows bidirectional oscillation is experimentally demonstrated in the L-band. Through leveraging a double-peak intracavity gain spectrum, two pulse trains in two nonoverlapping wavelength bands are shown to counter-propagate in the simple ring cavity. Ultrashort soliton pulses of \(\sim 800\) fs or less can be stably generated in both directions. It is also demonstrated that bidirectional operation within one of the wavelength bands can also be achieved with much smaller center wavelength separations by tuning the gain spectrum. The repetition rates of the two pulse trains have a slight difference due to the intracavity dispersion. Thus, the directional- and wavelength-multiplexed output from such a cavity-diversity-enabled ultrafast laser could potentially be leveraged in those applications requiring a dual-comb source.