公开(公告)号：US4070091A

公开(公告)日：1978-01-24

申请号：US677750

申请日：1976-04-16

申请人： John Charles Wood Taylor ,  Felix Paul Kapron

发明人： John Charles Wood Taylor ,  Felix Paul Kapron

IPC分类号： G02B6/44 ,  H04B10/12 ,  G02B5/14

CPC分类号： H04B10/85 ,  G02B6/4469

摘要： An optical fibre has a light conducting core surrounded by first and second cladding layers of sequentially lower refractive index. A data-carrying signal can be propagated in the core and a monitoring signal--of a higher modal order than the data signal--can be propagated in the core and first cladding layer. Any attempt to rap the fibre and abstract data information results in aberration of the monitor signal, which can be detected. The monitor signal can be such that resolvable signals cannot be obtained from the data channel by a tap.

摘要翻译： 光纤具有由依次较低折射率的第一和第二覆层围绕的导光芯。 数据承载信号可以在芯中传播，并且可以在芯和第一覆层中传播比数据信号更高模态次序的监测信号。 任何试图拉伸光纤和抽象数据信息都会导致监视信号的像差，这可以被检测。 监视信号可以使得通过水龙头不能从数据通道获得可解析信号。

公开(公告)号：US3988614A

公开(公告)日：1976-10-26

申请号：US591498

申请日：1975-06-30

申请人： Felix Paul Kapron ,  John Charles Wood Taylor

发明人： Felix Paul Kapron ,  John Charles Wood Taylor

IPC分类号： G02B6/34 ,  H04B10/18 ,  G02B5/14 ,  H01J5/16

CPC分类号： H04B10/25133 ,  G02B6/29361 ,  G02B6/29373 ,  G02B6/29394 ,  G02B6/4215 ,  Y10S359/90

摘要： The chromatic pulse dispersion of a light beam in an optical fibre can be equalized by dispersing the light beam into a spectrum, detecting different portions of the spectrum and producing signals related to each portion, applying different time delays to the signals and then combining the signals to provide an output. The spectrum can be divided into discrete portions having a range of wavelengths, with optical delay lines, optical filters, and multiple section photodetectors used. The spectrum can be formed on one surface of a PIN diode, having the I layer of a thickness which varies along the length, giving in effect division of the spectrum into an infinite number of portions.

摘要翻译： 可以通过将光束分散到光谱中来平衡光纤中的光束的色散脉冲色散，检测光谱的不同部分并产生与每个部分有关的信号，对信号施加不同的时间延迟，然后组合信号 提供输出。 频谱可以分为具有波长范围的离散部分，具有光学延迟线，光学滤波器和使用的多个部分光电探测器。 光谱可以形成在PIN二极管的一个表面上，其具有沿着长度变化的厚度的I层，实际上将光谱划分成无限数量的部分。

公开(公告)号：US4067642A

公开(公告)日：1978-01-10

申请号：US711419

申请日：1976-08-03

申请人： Frederick David King ,  Felix Paul Kapron

发明人： Frederick David King ,  Felix Paul Kapron

IPC分类号： G02B6/42 ,  G02B6/00 ,  G02B6/02 ,  G02B6/14 ,  G02B6/34 ,  H04B10/2507 ,  H04B10/2513 ,  G02B5/14

CPC分类号： G02B6/268 ,  G02B6/29311 ,  G02B6/29374 ,  G02B6/29394 ,  H04B10/2525

摘要： Modal dispersion and chromatic material dispersion in a multimode optical fiber is reduced by feeding the rays of the light beam into the end of the optical fiber the angle of each ray relative to the axis of the fiber varied in accordance with the wavelength of the ray. The shortest ray is fed at a zero angle and the longest wavelength at angle of .phi. max. .phi. max. is defined by the equation ##EQU1##This invention relates to the reduction of both modal and chromatic material dispersion in a multimode optical fibre.Multimode guides are currently used in fibre-bundle optical communications and will also appear in the next generation of individual-fibre systems. Their 50 to 100.mu.m diameter cores are compatible with multimode LED sources and simple connecting and tapping techniques. Unfortunately, their information carrying capacity is limited by the variation of signal group velocity both with mode number and with light wavelength; this presents a serious limitation with large numerical aperture fibres and broadband sources.Prior art in this field has concentrated on gradient-index optical fibres to approximately equalize all ray paths and hence reduce mode dispersion. However, these require fabrication procedures more complex than for step-index guides, are capable of accepting only about half as much light from an LED and neccessitate twice the curvature radius in bends. Source collimation to excite only low order modes can reduce mode dispersion. Differential mode attentuation reducing the role of higher order modes and intermodal coupling tending to average the resultant modal velocity are both effective, but these processes are inherently lossy. All the above methods reduce modal but not chromatic material dispersion. A technique for reducing chromatic material dispersion is disclosed in copending application, Ser. No. 591,498 filed June 30, 1975 in the name of the present assignee, now U.S. Pat. No. 3,988,614.The present invention provides for the suitable alteration of the angular light distribution entering the fibre so as to oppose the modal and chromatic effects, thereby achieving a substantial reduction in the net dispersive pulse broadening.

摘要翻译： 通过将光束的光线馈送到光纤的端部，每个射线相对于光纤的轴线的角度根据射线的波长而变化，从而减少多模光纤中的模态色散和色散分散。 最短的光线以零角进给，最长的波长以最大角度进给。 最大 由等式定义本发明涉及多模光纤中的模态和色散材料色散的减小。