掺镱硼酸钙氧钇飞秒激光器及在拉锥光纤中产生跨倍频程超连续光∗

摘要

跨倍频程超连续光谱的产生是光学频率梳系统中测量载波包络相移频率的关键.本文采用拉锥单模光纤作为非线性光谱展宽介质,将半导体激光(LD)抽运的掺镱硼酸钙氧钇(Yb：YCOB)振荡器输出的飞秒激光耦合到该拉锥光纤中,通过飞秒激光在光纤中发生的相位调制、四波混频等非线性效应将光谱展宽至超过倍频程的范围.振荡器输出的飞秒激光脉冲宽度为130 fs,中心波长为1052 nm,重复频率为76.8 MHz,平均功率为620 mW,耦合进单模拉锥光纤后获得了光谱覆盖范围从550 nm至1350 nm的跨倍频程超连续光谱,最大输出平均功率为323 mW,耦合效率达到52%.为进一步实现全固态飞秒激光光学频率梳提供了重要基础.%It is a pivotal step in the measurement of carrier-envelope phase offset frequency in optical femtosecond frequency combs that a stable octave-spanning super-continuum spectrum is generated. In this paper, a home-made Yb:YCOB femtosecond laser pulse is led into a tapered fiber in which some nonlinear effects like self pulse modulation are generated and the four-wave mixing is made to broaden a spectrum to more than one octave-spanning. A Yb:YCOB oscillator emits 130 fs, 620 mW and 76.8 MHz laser pulses, the center wavelength at 1052 nm. Such pulses are focused into a tapered single-mode fiber, and then more than one octave-spanning supercontinuum from 550 nm to 1350 nm has been produced. The coupling efficiency can reach 52%when 323 mW SC laser pulses are detected. Based on the experimental result, a new optical comb will be built with the Yb:YCOB solid state laser as the light source.