基于MgO:PPLN晶体的1554.8nm倍频器

1554.8 nm frequency doubler based on MgO:PPLN crystal

为满足风云四号气象卫星搭载的闪电成像仪图像定位精度检验的光源需求,设计了一台基于两级主振荡功率放大器结构(MOPA)和掺氧化镁的周期极化铌酸锂(MgO:PPLN)晶体倍频技术,中心波长为777.4 nm,连续输出功率为1.5 W的激光器。采用反向940 nm off-peak泵浦方式较好地抑制了光放大器中自激放大辐射(ASE)和受激布里渊散射(SBS)效应,主放大器光-光转换效率达37.2%,获得了输出光功率为15 W,信噪比为59.6 dB,线宽为323.4 kHz,相对强度噪声为-145 dBc/Hz的单频窄线宽激光。在理论分析所用MgO:PPLN晶体倍频效率、温度调谐带宽以及可接收的波长带宽基础上,采用单通倍频方式获得了功率为1.5 W的777.4 nm连续光。

To meet the light source requirement for image positioning of the lightning imager on board the Fengyun-4 meteorological satellite,a laser with a central wavelength of 777.4 nm and a continuous output power of 1.5 W is designed based on a two-stage master oscillation power amplifier structure(MOPA)and a periodically polarized lithium niobate crystal doped with magnesium oxide(MgO:PPLN)to double the frequency.Using 940 nm off-peak pumping technology to suppress the amplified spontaneous emission(ASE)and stimulated Brillouin scattering(SBS)in the optical amplifier,we obtain a single-frequency narrow linewidth laser with an output power of 15 W,a signal-tonoise ratio of 59.6 dB,a linewidth of 323.4 kHz,and a relative intensity noise of-145 dBc/Hz.The optical-optical conversion efficiency of the amplifier is up to 37.2%.Based on the theoretical analysis of the doubling efficiency,temperature-tuned bandwidth,and acceptable wavelength bandwidth of the MgO:PPLN crystal used,777.4 nm continuous light with a power of 1.5 W is obtained using a single-pass doubling method.