基于正常色散硫系波导的宽可调谐中红外频谱转换

Widely Tunable Mid-Infrared Spectral Translation in Chalcogenide Waveguide with Normal Dispersion

中红外-近红外频谱转换是实现诸多中红外波段应用的重要技术,转换效率和调谐范围通常由于泵浦-信号频率失谐量大而受限。提出一种新型As2Se3硫系光波导,通过色散调控对波导结构进行优化设计,使光波导在2μm波长附近具有正常群速度色散及负的四阶色散,达到泵浦-信号频率失谐量大的四波混频过程的相位匹配。研究了该波导的中红外-近红外频谱转换性能。结果表明,当泵浦光波长位于靠近零色散点的正常色散波长区时,可以实现宽范围可调谐的高效率频谱转换。通过调节泵浦光波长在(1955±30)nm范围内变化,实现了2.7~6.2μm中红外光波的频谱转换及参量放大,可调谐范围达到3.5μm。该波导有望应用于宽可调谐中红外激光产生及中红外信号的高灵敏度探测。

Mid-to-near-infrared spectral translation plays an important role in various applications in mid-infrared spectral range. However, the conversion efficiency and spectral tuning range were usually limited by the large frequency detuning between the pump and mid-infrared signal. In this work, a As2 Se3 chalcogenide waveguide was proposed to fulfill phase matching condition in four-wave mixing with large pump-signal frequency detuning. The waveguide geometry was optimized through dispersion engineering to provide normal group velocity dispersion and negative fourth-order dispersion around 2 μm. The mid-to-near-infrared spectral translation with high efficiency and wide-band tunability was facilitated. By using a pump wavelength in the normal dispersion regime, the spectral translation and parametric amplification of midinfrared signal ranging from 2. 7 to 6. 2 μm is obtained. The proposed waveguide has great potentials in high-sensitivity detection of mid-infrared signals and widely tunable mid-infrared generation.