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

通过单模光纤传输具有复幅度的并行数据阵列是一项具有挑战性的任务，这些数据阵列分布在二维空间中，并且在时间上变化，例如具有超高空间分辨率和许多灰度级的动态全息图。相干技术适合于在不进行模数转换的情况下同时传输幅度和相位。通过写入脉冲的光谱全息图并用连续波激光器将其读出，将时间信息转换为一维空间信息，以及相反的过程，即，将一维空间图案转换为具有4-f光学布置的时间图案(脉冲整形)，将产生一种新的通过单模光纤的一维空间数据的相位和幅度的模拟传输方案。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，得到了以下结论：(1)传输…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后的更多一维空间位相信息。基于一维空时转换技术和码分多址技术，提出了一种利用飞秒激光脉冲通过单模光纤进行二维并行数据传输的方案，并进行了数值模拟。提出了一种全光分组路由器，并对其基本功能进行了实验验证。该光路由器是由角度复用的光谱全息图组成的光路由器，其工作原理是将数据流卷积到预定的衍射角。较少

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