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All Fiber MHZ Yb-doped Picosecond Pulse Amplifier

Posted on:2018-12-16Degree:MasterType:Thesis
Country:ChinaCandidate:X X WangFull Text:PDF
GTID:2348330563952268Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Ultrashort laser pulses with high energy and high beam quality are widely used in the fields of ultrafast nonlinear opticsand optical frequency comb.Especially the high power and high energy of the femtosecond pulse laser,due to its interaction with material,the heat effect is small,no melting zone around the processing aperture,ithasa widerdemand in the field of ultra precision machining,micro photonic device manufacturing,precision medical surgery,nano bio engineering and national defense laser weapons.This paper carried out theoretical analysis and experimental research on ultrashort pulse fiber amplifier,including fiber oscillator,pulse selector,fiber amplifier,solid compressor.The main work of this paper is as follows:The first partdemonstrates the theoretical research of the mode-locked fiber oscillator,which mainly include the physical mechanism of the mode-locked and several main methods for implementing the mode-locked.Meanwhile,the expressions of pump powerand amplified pulses power for single-pass plused amplifier are introduced with thebasis of the expressions of rare equations,andthe influence of dispersion and nonlinear effect on pulse transmission in fiber amplifier are also analyzed.The second part demonsrates theexperimental investigation of chirped pulse amplification system.According to the mechanism of dispersion compensation of grating pair,a chirped pulse amplification system is built,theseed source usedthe SESAM mode-locked fiber oscillator whichoperates at 1031.3nm with a spectral width of 1.51 nm.Its pulse width is 3.1ps with 21.3269 MHz.Moreover,the system used the simplified chirped pulse amplification technique,that is to say,there is none of the stretcher,we utilize the nonlinear pulse amplification technique,the output signal of the oscillator stage is amplified directly,the amplifier is used the main oscillator power amplifier.When the average output power of the amplifier is 2W and the pulse width is 3.2ps,the amplified pulse is compressed.Compressor is used the reflection gratings.When the grating spacing is 109 mm,the minimum pulse width of 260 fs is abtained,By fine grating spacing,When the grating spacing is 120 mm,the minimum pulse width of 240 fs is obtained.Laser pulses with pulse duration of 240 fs aregenerated by a reflective grating-pair compressor,corresponding to average power of 306 mW,single pulse energy of 14.6 nJ and peak power of 6.1kW.The third part investigates experimental study on supercontinuum generation of picosecond pulse amplifier.A wide spectral picosecond pulse amplifieris build in all fiber configuration based on the physical mechanism of supercontinuum generation in fiber amplifiers.The seed source is passively mode-locked by semiconductor saturable absorber mirror(SESAM)which operates at 6.41 mW with a repetition frequencyof 21 MHz.Its center wavelength is 1031 nm with a spectral width of 1.51 nm,pulse width is 3.1ps.An accouto-optical modulator is applied to reduce the repetition rate from 21 MHz to 2.1MHz.After three stages of fiber amplification,we obtain the laser performance with spectrum of 640-1700 nm,average output power of 20 W,pulse width of 20.8ps,pulse energy of 9.5?J,peak power of 0.46 MW in the 30/250 um large mode field double clad Yb-doped fiber.
Keywords/Search Tags:SESAM mode-locked fiber oscillator, All fiber MOPA amplifier, CPA, Supercontinuum
PDF Full Text Request
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