Research On Multi-Wavelength Tunable Femtosecond Optical Parametric Oscillator

Highly efficient generation of widely tunable and high average power femto-second laser source from yellow to mid-infrared is obtained based on nonlinear opti-cal parametric conversion technique, which is pumped by an Yb-dopedlarge-mode-area photonics crystal fiber laser. Optical parametric oscillator (OPO) is acontinuously wavelength tunable laser source that laser cann’t directly produce.Large-mode-area of ytterbium doped photonic crystal fiber laser has high averagepower, high conversion efficiency, compact structure and high reliability advantages,so using large mode field area of femtosecond optical parametric oscillator combinewith intracavity sum-frequency is a good way to produce high average power laser.This thesis mainly focuses on second-order nonlinear process, we present an experi-mental and a theoretical analysis of the femtosecond optical parametric oscilla-tors(OPOs) based on MgO doped periodically poled LiNbO3(MgO:PPLN) andlithiumborate(LBO), to achieve a widely-tunable, high power, ultrafast femtosecondlaser source. The main contents of this dissertation are listed as follows:1. Theoretically, we design a femtosecond OPOs pumped by an Yb3+-doped sin-gle-polarization double cladding LMA PCFs. We introduce the theory of femtosecondlaser and fiber laser; nonlinear optics; optical parametric oscillator; quasi-phasematching (QPM) based on periodically poled crystals. And output wavelength tunedcharacteristic of femtosecond OPOs based on MgO:PPLN crystal is calculated theo-retically.2. We have designed and constructed a femtosecond OPOs in a MgO-doped pe-riodically poled LiNbO3pumped by an Yb3+-doped single-polarization double clad-ding LMA(large-mode-area) PCFs (photonic-crystal-fibers). Femtosecond pulsesfrom red to mid-infrared have been obtained by intracavity sum-frequency genera-tion(SFG) in the OPO.3. A dual-wavelength, double cavity femtosecond optical parametric oscillatorbased on a temperature-tuned LiB305and synchronously pumped at520nm by a fre-quency-doubled Yb:fiber laser is reported. The observed dual-wavelength tuning is inagreement with the values predicted by computer simulation. Moreover, sum fre- quency yellow laser of the longer signal and the other’s idler with practical power isalso achieved.