面向室温高灵敏度中红外探测的片上参量光信号处理技术研究

Mid-infrared (Mid-IR) spectral range is the window for a wide variety of important applications, such as spectroscopy, biomedical applications, and remote sensing. High performance detection with room-temperature operation and compact structure is necessary to facilitate these applications. Efficient, low-noise and integrated parametric optical signal processing is an efficient approach for room-temperature high-sensitivity mid-IR detection. However, current parametric signal processing for mid-IR signals still have the problems of low efficiency, large noise and low integration level. This project proposes to use dispersion engineered chalcogenide waveguide to achieve efficient, low-noise and integrated parametric optical signal processing. We will investigate the effect of waveguide design on tailoring of dispersion and nonlinear properties in order to optimize the waveguide design for efficient on-chip distant parametric interactions. In addition, a mid-IR indirect detection scheme based on on-chip parametric frequency conversion will be studied. We will focus on the effect of key parameters in the parametric process on electrical signal-to-noise ratio in the proposed detection scheme in order to optimize the detection performance. Furthermore, we will investigate and demonstrate phase-sensitive parametric amplification for mid-IR signals using the chalcogenide waveguide, which is promising for ultra-low noise amplification and high-sensitivity detection of the mid-IR signals. The research on on-chip parametric signal processing in this project will open a new way for high performance and compact mid-IR detection at room temperature, which have important application perspectives.

室温工作、小型化的中红外高性能探测在光谱分析、医疗诊断、遥感等中红外应用领域具有关键作用，而高效率、低噪声、可集成的参量光信号处理技术是实现室温下高灵敏中红外探测的一种有效方案。目前中红外参量光信号处理技术仍存在效率较低、噪声较大、集成度较差的问题。本项目针对此问题，提出采用色散调控高非线性硫系波导，结合理论分析与实验方法，获得高效率低噪声片上参量光信号处理的实现方法。项目拟研究波导结构对色散及非线性系数的调控机制，优化波导设计，研制高效的光参量器件；研究基于中-近红外频率转换的间接探测方案，着重分析频率转换过程各关键参数对探测信噪比的影响，获得高性能探测方案；研究中红外波段相位敏感光参量放大过程的机理与特性，探索基于该过程的中红外信号超低噪声放大及高灵敏探测的新方法。本项目在参量光信号处理技术方面的研究将为实现室温下高性能、结构紧凑的中红外探测提供新的途径，具有重要的科研意义和应用前景。

室温工作、小型化的中红外高性能探测在光谱分析、医疗诊断、遥感等中红外应用领域具有关键作用，而高效率、低噪声、可集成的参量光信号处理技术是实现室温下高灵敏中红外探测的一种有效途径。本项目围绕面向中红外探测的片上参量光信号处理技术在效率、噪声等方面的关键问题开展研究，主要包括：（1）针对中-近红外波段之间大跨度频谱转换的效率与噪声问题，提出一种基于正常色散的相位匹配方案，并通过色散调控优化设计硫系波导，实现了2.7~6.2um的宽可调谐中红外频谱转换以及宽带量子噪声的抑制。（2）研制了低损耗硫系波导，波导具有低的传输损耗（0.2dB/cm）和非线性损耗，为高效率中红外参量频率转换的实现提供了器件基础；揭示了硫系波导芯层材料和包层材料对受激布里渊效应的影响，为参量频率转换过程中抑制受激布里渊效应导致的噪声提供了新思路。（3）研究了面向中红外探测的相敏放大实现方案，揭示了相敏光参量放大的增益对信号噪声的影响；提出了基于低泵浦功耗相敏放大的高灵敏度探测方案并进行实验演示，包括混合式相敏光放大技术，实现了增益高达45.6dB、噪声指数低至2.0dB的光放大，以及利用相敏放大过程的相干功率重分布特性的带内噪声抑制技术，实验上演示了30.6dB的信噪比提升；另外还充分利用项目资源发展了基于相敏四波混频的大带宽高灵敏度瞬时频率测量技术。在项目组全体成员的共同努力下，项目执行期间，公开发表论文9篇，获得授权发明专利1项，结合项目课题培养硕士研究生5名，博士研究生1名。