Optical parametric generation and optical parametric oscillation in monolithic PPLN crystals

• Main Authors: LAU CHEE WAI, 劉志偉
• Other Authors: Prof. Yen-Chieh Huang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/14875399518241344541

碩士 === 國立清華大學 === 電機工程學系 === 91 === Periodically Poled lithium niobate (PPLN) has become the nonlinear-optical material of choice in many tunable optical parametric processes. The fabrication techniques are well developed and can produce device quality PPLN crystals. The focus of the research was designing monolithic optical parametric generation (OPG) and optical parametric oscillator device. Optical parametric generation device is a most popular tunable laser source. Much pump power is not contribute more conversion efficiency again. We demonstrated pump depletion and back conversion process are limited conversion efficiency for the OPG process. Suitable pump power will get the most conversion efficiency in the OPG process. Due to high pump threshold and wide line widths cause the optical parametric oscillators developed. However, conventional cavity method will make the laser system complex, difficult alignment. We demonstrated flat-flat mirror OPOs by using coating method to replace the cavity mirror. It will get low threshold, high conversion efficiency and compact than conventional method. For 24mm length PPLN, we get 46% high efficiency, and the pump threshold only is 0.069J/cm2. Since the flat-flat mirror OPOs have been demonstrated, but alignment problem also to be exist. We demonstrated distributed feedback (DFB) optical parametric oscillation (OPO) by using electro-optic effect in the periodically poled lithium niobate. Use 532nm pump to 12μm PPLN chip to generate wavelength 589nm. We design the DFB grating period is 8th order at the idler is near 5.5μm. Although the idler wavelengths have strong absorption above 5.5um, but we still observe DFB effect by apply voltage until 1000V at 120℃.