Study On Supercontinuum Genration In All-Fiber-Integrated Holmium-doped ZBLAN Fiber Amplifier

As the technology of supercontinuum?SC?laser sources is developed,the long-wavelength-dege?LWE?of SC laser spectrum has been continually extending into mid-infrared?MIR?region.Recently,MIR SC based on soft-glass fiber amplifiers draws much attention since they have shown their attractive merits in long operating wavelength,simple configuration,and convenience to achieve further SC extension by cascading other types of nonlinear fibers.This thesis concentrates on theoretical and experimental studies of MIR SC laser source based on all-fiberized holmium-doped ZBLAN fiber amplifier?HDZFA?.The primary contents are shown as follows.1.Supercontinuum generation in HDZFA was numerically simulated based on the mathematical model that combined the generalized nonlinear Schrodinger equation?GNLSE?and the dynamic rate equation.The influence of different signal wavelength,the absorption peak of Ho³⁺,and the length of gain fiber on the spectral performance of generated SC was studied.It was pointed out that:?a?if 2050-nm pulses were injected into HDZFA,SC with flat spectrum could be expected;?b?the strong absorption peak at².7-2.8?m of Ho³⁺was to account for the limited LWE of generated SC spectrum.2.The first study on SC generation in ZBLAN fiber amplifier based on holmium-doped ZBLAN fiber was carried out.The first demonstration of SC laser source based on an all-fiber-integrated HDZFA was achieved via in-band pumping scheme.Such SC laser source had a maximum output power of 248 mW with a spectral range of 2.1-2.9?m.Further scpetrum broadening of SC was achieved by the scheme where the SC source was used to pump a piece of nonlinear fiber.In an elementarily optimized case,a piece of 11-meter-long non-doped ZBLAN fiber was cascaded to the HDZFA and a SC was obtained with a spectral range of 2.1-3.7?m and a maximum output power of 89.2 mW.3.Elementary study on SC generation of>3?m based on 2.86-?m-seeded all-fiberized HDZFA was carried out.As to seed sources,a 0.6 to 3.2?m ultra-broadband all-fiber-integrated SC laser source was achieved in a piece of germania-core fiber?GCF?.To achieve all-fiberized ZBLAN fiber amplifier operating at 3-?m waveband,a type of side-pumped,GCF-and-silica fiber based fiber combiner wasproposed.Furthermore,Ultra-broadbandSCsourceschemeof dual-wavelength-amplification in Er³⁺:ZBLAN fiber amplifier based on Er³⁺:ZBLAN fiber or Ho³⁺:ZBLAN fiber was proposed.Such scheme could adequately extract the energy of the pump photon,improve the slope effieiency,and achieve ultra-broadband SC output while the heat load of the amplifier was greatly reduced.