Investigation Of Infrared Fiber Laser And Femtosecond Laser Direct Writing Optical Waveguide

Q-switching and mode-locking technique are two effective and universal methods on generating ultra short pulses, whereas passive mode-locking and Q-switching are intensively investigated because of compact and low cost. Femtosecond(fs) pulse has the incomparable advantages over others processing tools in the field of micro-machining due to its extremely short pulse width and high peak power. The effect of nonliner absorption of fs pulse in transparent materials provide in efficient approach to compensate the shortage of conventional machining method. The stable Q-switching and mode-locking all fiber laser based on a newly saturated absorber paper is proposed in the thesis. In addition we employ fs laser direct writing technology to inscribe optical waveguide in the chalcogenide glass and obtain quality single mode waveguide at the wavelength of 1039 nm. Our main works are present as follow:1. Set up the 1μm all fiber graphene oxide Q-switching laser and the stable Q-switching pulse with which has the highest repetition rate of 70 KHz, the shortest pulse width of 1.6μs, and the highest output power of 3m W at 1030 nm is realized.2.Design and set up 1μm all fiber single wall carbon nanotube Q-switching laser and the stable Q-switching pulse with the repetition rate of 58 KHz, the highest pulse energy of 37 n J, and output wavelength at around 1030 nm is proposed and obtained.3.We realize the mode-locking and harmonic mode-locking in 2μm all fiber laser, the fundamental frequency mode-locking has the repetition of 17 MHz and the harmonic modelocking up to 300 MHz. Multiple pulse such as pulse bundle, pulse bunch and double pulse is alse observed. Output threshold decreases from 1.7W to 1.5W by optimizing the loss in the fiber cavity. In addition, the stability of the mode locking is also enhanced.4.We successfully fabricated the optical waveguide in the chalcogenide glass using fs laser direct writing technology. To the best of our knowledge, this is the first fabrication of the single line waveguide in the chalcogenide glass using fs laser direct writing technology. We confirm the most optimum inscribed parameters that the pulse energy is 0.8μJ and the scanning speed is 100μm/s, the corresponding transmission loss is 0.86 d B/cm. The near field mode and transmission losses through different optical guides at 1μm laser was measured. We find the chalcogenide glass has stronger nonlinear absorption than the fused quartz, phosphate glasses and the quality single mode waveguide at ?=1039nm.5.We further study the feasibility of micro waveguide in the sapphire crystal using fs laser. We inscribe double lines waveguide still choosing fs laser direct writing technology and achieve good result. In the experiment we not only testify the feasibility in the sapphire which has high hardness but also obtain excellent double line waveguide under the pulse energy of 10μJ, near field profile is nearly single mode. The lowest transmission losses are 0.64 d B/cm at 1μm. The transmission losses are low than others chalcogenide glass waveguide so the chalcogenide waveguide can act as fine optical micro component.