Low-Threshold Mid-Infrared Continuous-Wave Optical Parametric Oscillator And High-Stability Compact Product Research

3-5?m mid-infrared(MIR)lasers are of great interest in laser field,with a great number of applications in many fields.Normal solid laser medium cannot cover this range of wavelength.Optical parametric oscillation(OPO)is a good way to generate mid-infrared(MIR)lasers,with advantages of flexible tunability,high output power,compactness and so on.In this thesis,we demonstrated intra-cavity continuous-wave(CW)optical parametric oscillators and ring-cavity continuous-wave optical parametric oscillators in the basis of quasi-phase matching(QPM)technique.There are few institutes producing MIR lasers in China.Because MIR lasers involve military purposes,it's hard to directly buy them from other countries.For meeting market needs,we produced two engineering machines.By engineering technology,we reduced the volume of lasers and enhanced the reliability of them.The main content is as follows:1.The background,application fields and generating methods of mid-infra-red lasers were briefly introduced.The principal of quasi phase matching and optical parametric oscillating technology was expounded.The classification of optical parametric oscillators was discussed.2.We elaborated the theory of optical parametric oscillators,including the calculation of gain and threshold condition of optical parametric oscillators,wavelength tuning property of OPO,common cavity shapes and so on.3.We studied the mid-infrared(MIR)continuous-wave(CW)intra-cavity optical parametric oscillators(IC-OPO).We set up compact linear cavity IC-OPO by rationally designing optical parameters.By adding aperture slot and KTP,we resolved problems inherent in IC-OPO such as instability of output power,long-lived bursts of relaxation-oscillations.Compared with extra-cavity OPO,IC-OPO is more compact,and it's threshold is lower.Thus,IC-OPO is suitable for the applications which need mid-infrared laser with low power.We designed a compact and highly stable IC-OPO engineering machine using water-cooling technology and fixed mirror mounts instead of commercial ones and got mid-infra-red laser output with high stability.We used steering engine to control channels of superlattice.According to testing results,reliability of the machine can meet the needs of market.4.The technique of the continuous wave(CW)extra-cavity OPO was studied.A fiber-amplified distributed feedback(DFB)laser was used to pump OPO.We demonstrated OPO based on MgO:PPLN with multi-periods,from which we got the output wavelength from 1.5?m to 4.3?m.Output in 3.3?m was used in the gas detection experiment.The market requirement of high-power mid-infra-red lasers is increasing.We designed a light-weight ring-cavity OPO machine using carbon fiber,in which mirrors and optical supperlattice were glued.Thus,long-term stability is effectively improved.In addition,we used steering engine to control the channels of muti-periods optical superlattice instead of stepping motor,lowering the cost of machines under the premise of ensuring the precision.According to testing results,reliability of the machine can meet the needs of market,so it's hopeful to standardize and volume produce this kind of OPO.