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

通过单模光纤模拟传输全息图的时空转换系统

基本信息

批准号：
12650349
负责人：
KANNARI Fumihiko
金额：
$ 2.24万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

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

通过单模光纤传输具有复杂幅度的并行数据阵列（分布在二维空间中并且随时间变化），例如具有超高空间分辨率和多个灰度级的动态全息图，是一项具有挑战性的任务。相干技术适合传输幅度和相位，无需模数转换，通过写入脉冲的光谱全息图并用连续波激光将其读出，将时间信息转换为一维空间信息。逆过程，即，利用 4-f 光学布置将一维空间模式转换为时间模式（脉冲整形）将产生一种通过单模光纤传输一维空间数据的相位和幅度的新型模拟传输方案。研究中，我们对几种基于时空转换的方案进行了实验检验，得到如下结论：（1）通过使用实验证明了低相干光通过单模光纤传输一维空间相位信息。的时空转换4-f傅立叶相干函数整形器和发射机引起的光谱全息时空转换限制了一次相干函数整形可传输的信息容量。(2)一种二维并行数据传输的新方案。飞秒激光脉冲通过单模光纤，基于一维时空转换技术与码分多址相结合，以 16 位 x 的形式实现并数值演示了二维数字图像。 16位平面被单个飞秒激光脉冲成功传输，等效传输速率为1.6 Tbit/s，并通过光谱全息术恢复。（3）提出了一种全光分组路由器，并通过实验证明了其基本功能。角度复用光谱全息图的工作原理是将数据流（其自身的 M 序列代码进行卷积）路由至预定义的衍射角。