Research On1μm All-fiber All-normal Dispersion Mode-locked Laser Induced By Carbon Nanotube Saturable Absorber

1μm all-fiber laser based on ytterbium-doped fiber (YDF) has been widelyresearched owing to its simple structure, low cost, wide radiation bandwidth and highoutput power. Continuously tunable laser, Q-switched laser and mode-locked laser areimportant development directions of1μm fiber laser. In this paper, we focus oncontinuous wavelength-tunable all-fiber laser, passively Q-switched and passivelymode-locked all-fiber lasers around1μm, and carry out the theories, simulations, andexperimental research of these lasers.First, we described the principle of the single-mode-multimode-single-modemultimode interference filter (SMS), which can realize a tunable fiber laser. Then wedescribed the principle of Q-switching and mode-locking induced by carbon nanotubesaturable absorber (CNT-SA), and some important factors of1μm all-normaldispersion (ANDi) mode-locked fiber laser, including dispersion, nonliner effect andgain of the fiber. Moreover, we deduced Ginzburg-Landau equation (GLE), whichdescribes the propagation characteristics of pulse in ANDi mode-locked fiber lasercavity.We also done some work of numerical simulations. We solved the GLE, whichdescribes the propagation characteristics of mode-locked pulses. Moreover, wesimulated and analyzed the effects of some different factors of the laser, includingmode-locked mechanisms, bandwidth of spectal filter, pump power, saturableabsorber and cavity length.The experimental research started with the fabrication of SMS. Then we realizeda continuous wavelength tunable fiber laser by using the SMS, the tuning range isabout1020nm~1035nm. We prepared and charactered CNT-SA with1nm diameter,and realized a1μm passively Q-switched fiber laser by using it. The pulsewidth,repetition rate and pulse energy are4.5μs,25KHz and140nJ respectively. What’smore, we prepared and charactered CNT-SA with0.8nm diameter, which isabsorption-stronger around1μm, and we realized a gain-guided soliton fiber laserand a dissipative soliton fiber laser with100ps magnitudes output pulses by using it. Moreover, we researched some important factors of the laser, includingconcentration of CNT-SA, cavity length, polarization states. A tunable1μmgain-guided soliton laser (1032nm~1040nm), and a dual-wavelength (1037nm and1039nm)1μm gain-guided soliton laser were realized by adjusting the polarizationcontroller (PC).