Time-space conversion system for analog transmission of holograms through single-mode fibers

具有复振幅的并行数据阵列的传输，其分布在二维空间中并且也随时间变化，例如，通过单模光纤获得具有超高空间分辨率和许多灰度级的动态全息图是一项具有挑战性的任务。相干技术适合在没有模数转换的情况下传输幅度和相位。通过写入脉冲的光谱全息图并用连续波激光阅读，将时间信息转换为一维空间信息，以及逆过程，即，利用4-F光学装置将一维空间图案转换成时间图案（脉冲整形）将导致通过单模光纤的一维空间数据的相位和幅度的新颖模拟传输方案。在本研究中，我们对几种基于时空转换的方案进行了实验研究，得到了如下结论：（1）传输 关于我们 利用4-f傅里叶相干函数整形器的时空转换和光谱全息的时空转换，实验证明了低相干光通过单模光纤时一维空间相位信息的提取。发射机引起的空时耦合限制了单次相干函数成形可传输信息的容量。(2)基于一维空时转换技术和码分多址技术，实现了飞秒激光脉冲在单模光纤中的二维并行数据传输，并进行了数值模拟。利用单脉冲飞秒激光以1.6Tbit/s的等效传输速率成功地传输了16位× 16位平面上的二维数字图像，并通过光谱全息术恢复了图像。(3)提出了一种全光分组路由器，并对它的基本功能进行了实验验证。该路由器由角度复用的谱全息图组成，其工作原理是将M序列码卷积后的数据流路由到预定的衍射角。少

Transmission of parallel data arrays with complex amplitude, which distribute in a two-dimensional space and also temporally vary, e.g., a dynamic hologram with ultra high spatial resolution and many gray levels, through a single-mode optical fiber is a challenging task. A coherent technique would be suitable to transmit both the amplitude and phase without analog-digital conversion. The conversion of temporal information into one-dimensional spatial information by writing a spectral hologram of the pulse and reading it out with a continuous-wave laser, and the inverse process, i.e., the conversion of one dimensional spatial patterns into temporal patterns (pulse shaping) with a 4-f optical arrangement would lead to a novel analog transmission scheme for both phase and amplitude of one-dimensional spatial data through a single-mode fiber. In this study, we experimentally examined several schemes based on the time-space conversion and obtained the conclusions as follows:(1) Transmission … More of one-dimensional spatial phase information by low-coherence light through a single-mode fiber is experimentally demonstrated by use of space-time conversion at a 4-f Fourier coherence function shaper and time-space conversion with spectral holography. Space-time coupling caused by the transmitter limits the capacity of information transmittable with one coherence function shaping.(2) A new scheme for two-dimensional parallel data transmission with a femtosecond laser pulse through a single-mode fiber, which is based upon one-dimensional space-time conversion technique in conjunction with code division multiple access, is implemented and numerically demonstrated. Two-dimensional digital images in a 16 bits x 16 bits plane are successfully transmitted by a single femtosecond laser pulse at an equivalent transmission rate of 1.6 Tbit/s and recovered by spectral holography.(3) An all-optical packet router was proposed and its basic function was experimentally demonstrated The optical router consisting of angularly multiplexed spectral hologram works by routing the data stream, which is convoluted its own M-sequence code, to the pre-defined diffraction angle. Less