Theoretical analysis of the fiber-lens TEC （Thermally Expended Core） /Coreless/GRIN （Graded-Index） based on thin lens equivalence Js presented in this paper, On condition that the TEC part adjusts the waist radius...Theoretical analysis of the fiber-lens TEC （Thermally Expended Core） /Coreless/GRIN （Graded-Index） based on thin lens equivalence Js presented in this paper, On condition that the TEC part adjusts the waist radius of an incident Gaussian beam,that the coreless part controlls the space between the beam waist and the thin lens, and that the GRIN part acts as the thin lens with its focal length determined by fiber index distribution parameter g, the analytic expressions of the waist spot size and the working distance of the output Gaussian beam are derived, and the influence of the coreless fiber and the length of the GRIN fiber upon the fiber-lens parameter is discussed based on the numerical simulation results. It is concluded that, if a GRIN style fiber-lens is used as a collimator, the maximum of the spot waist can be up to 80μm and the divergence angle of single-mode optical fiber can be reduced by 8 times. If it is applied to a MEMS device, the maximum working distance can be up to 3 mm.展开更多
A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distri...A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distribution behind the output mirror of lasers, the radius and the M^2 factor describing the quality of beam can be measured. The waists of the multi-mode field and the TEM00 mode can be deduced according to the law of multi-mode Gassian beam propagation. Based on the ABOD matrix theory of a stable resonator,the thermal focal length of the active medium can be easily obtained. The thermal focal length of a LD end-pumped Nd. GdVO~ laser has been measured and the experimental results agree with the theoretically analyzed values.展开更多
文摘Theoretical analysis of the fiber-lens TEC （Thermally Expended Core） /Coreless/GRIN （Graded-Index） based on thin lens equivalence Js presented in this paper, On condition that the TEC part adjusts the waist radius of an incident Gaussian beam,that the coreless part controlls the space between the beam waist and the thin lens, and that the GRIN part acts as the thin lens with its focal length determined by fiber index distribution parameter g, the analytic expressions of the waist spot size and the working distance of the output Gaussian beam are derived, and the influence of the coreless fiber and the length of the GRIN fiber upon the fiber-lens parameter is discussed based on the numerical simulation results. It is concluded that, if a GRIN style fiber-lens is used as a collimator, the maximum of the spot waist can be up to 80μm and the divergence angle of single-mode optical fiber can be reduced by 8 times. If it is applied to a MEMS device, the maximum working distance can be up to 3 mm.
基金Supported by the National Natural Science Foundation of China(No.60478036)
文摘A simply method to measure the thermal focal length of a LD end-pumped Nd.GdVO4 solid state laser with a stable resonator is presented. By scanning a slit across the field with expression of multi-mode Gaussian distribution behind the output mirror of lasers, the radius and the M^2 factor describing the quality of beam can be measured. The waists of the multi-mode field and the TEM00 mode can be deduced according to the law of multi-mode Gassian beam propagation. Based on the ABOD matrix theory of a stable resonator,the thermal focal length of the active medium can be easily obtained. The thermal focal length of a LD end-pumped Nd. GdVO~ laser has been measured and the experimental results agree with the theoretically analyzed values.
