Dortaj Hannaneh, Faraji Mohammad, Matloub Samiye
Quantum Photonics Research Lab (QPRL), University of Tabriz, Tabriz, 5166614761, Iran.
Sci Rep. 2022 Jul 27;12(1):12778. doi: 10.1038/s41598-022-17084-4.
Recently, all-optical modulators are potentially the most promising candidate to achieve high-bit rate modulation in high-speed all-optical communication technologies and signal processing. In this study, a two-channel all-optical modulator based on a solution-processed quantum dot structure is introduced for two sizes of quantum dots to operate at two wavelengths of MIR spectra (3 µm and 5 µm). To perform numerical and theoretical analysis and evaluate the optical behavior of the proposed all-optical modulator, the coupled rate and propagation equations have been solved by considering homogeneous and inhomogeneous broadening effects. The modulation depth at the 50 GHz frequency and 3 mW probe power is attained, about 94% for channel-1 with the wavelength of 559 nm at 300 Wcm pump power density as well as approximately 83.5% for channel-2 with the wavelength of 619 nm at 500 Wcm pump power density. The introduced two-channel all-optical modulator can operate simultaneously at two wavelengths during the modulation process in which information could be transmitted through both signals from the control light. This approach can present the practical device as a high-contrast and high-speed two-channel all-optical modulator with a high modulation depth in numerous applications such as thermal imaging in night vision cameras, wavelength de-multiplexing, signal processing, free-space communication.
近来，在高速全光通信技术和信号处理中，全光调制器很可能是实现高比特率调制最具潜力的候选者。在本研究中，针对两种尺寸的量子点，引入了一种基于溶液处理量子点结构的双通道全光调制器，使其在中红外光谱的两个波长（3微米和5微米）下工作。为了进行数值和理论分析并评估所提出的全光调制器的光学行为，通过考虑均匀展宽和非均匀展宽效应求解了耦合速率方程和传播方程。在50吉赫兹频率和3毫瓦探测功率下实现了调制深度，在300瓦每平方厘米泵浦功率密度下，波长为559纳米的通道1的调制深度约为94%，在500瓦每平方厘米泵浦功率密度下，波长为619纳米的通道2的调制深度约为83.5%。所引入的双通道全光调制器在调制过程中可以在两个波长上同时工作，在此过程中信息可以通过来自控制光的两个信号进行传输。这种方法可以将该实用器件呈现为一种高对比度、高速的双通道全光调制器，在诸如夜视相机中的热成像、波长解复用、信号处理、自由空间通信等众多应用中具有高调制深度。
