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The Influence Of Pump-light On The Output Characteristics Of DPL

Posted on:2010-07-26Degree:MasterType:Thesis
Country:ChinaCandidate:X W LiuFull Text:PDF
GTID:2178360272982586Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
The spatial and temporal characteristics of Pump light will affect the characteristics of DPL, the paper studied the spatial characteristics (the spatial distribution) and temporal characteristics (pulse-pumped mode) of the pump light on the output characteristics of DPL. Finally, focusing on the application of pulse-pump in passive Q-switched laser pulse stability.As the first research point, the paper discussed the distribution of multi-fibers coupled laser diode. First, the thesis studies on the distribution of multi-fibers coupled laser diode, obtains the envelope of beam traveling trace, analyses the optical-field of light beam in different Z in depth, and discusses the corresponding relationship between the beam of multi-fibers coupled laser diode and super-gaussian beam.The second research point of the paper is how the distribution of pump light affects the quality of DPL. A model of super-gaussian is used to simulate the beam of multi-fibers coupled laser diode. The theory of overlap integral is introduced. And based on it, the paper discusses how radius of pumping beam and flattened degree affects the threshold pumping power. The result of how radius of pumping beam and flattened degree control the threshold pumping power is as follows:With the change of the flattened degree N, there is a minimization of threshold pumping power and when theωp /ωs raise, the position of this minimization appeared move to the N=2 end. The theory of affection factor of pump light is introduced. And based on it, the paper discusses how radius of pumping beam and flattened degree affects the beam quality of output laser. The result of how radius of pumping beam and flattened degree control the beam quality of output laser is as follows: with the change of theωp /ωs, there is a minimization of affection factor of pump light and this minimization always appears at the position ofωp /ωs= 1. Whenωp /ωs < 1, the affection factor of pump light changes swift. Whenωp /ωs> 1 the affection factor of pump light changes unconspicuous.The third research point of the paper is how the form of pump light affects the quality of DPL. The paper deeply discusses the factors which influence the stability of passive Q-switched laser, introduces the function of pre-pump power and main-pump power in pre-pumping technology, analyses the control of pre-pump power and main-pump power on the stability of passive Q-switched laser. How to get high frequency and high stability current pulse is the emphasis of this section. The paper put forward the concept of current adding switch. And through ameliorating the subsistent control circuit, a project of jumping current power supply is integrally presented to meet the request of pre-pumping technology. The current adding switch is designed and executed in this paper. In this plan, the power source system was make up of by the digital control circuit part and current adding switch part and constant current source part. The constant current source is used to supply the high stability and high precision pre-pump current. The voltage signal supplied by the digital control circuit is used to control the current adding switch and through it the pulse adding current is made. The adding current and the pre-pump current make up of the jumping current power. The emulational results under different frequency and different duty cycle testify the project can meet the request of high frequency(10MHz) jumping current.
Keywords/Search Tags:pre-pumping technology, current adding switch, passively Q-switched, multi-fibers coupled, flat-topped beam
PDF Full Text Request
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