CN101557257A - Fiber Rayleigh scattering signal detector - Google Patents
Fiber Rayleigh scattering signal detector Download PDFInfo
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- CN101557257A CN101557257A CNA2009100498800A CN200910049880A CN101557257A CN 101557257 A CN101557257 A CN 101557257A CN A2009100498800 A CNA2009100498800 A CN A2009100498800A CN 200910049880 A CN200910049880 A CN 200910049880A CN 101557257 A CN101557257 A CN 101557257A
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Abstract
The invention relates to a fiber Rayleigh scattering signal detector of the optical communications technology field. The invention comprises an elliptical quartz cylinder which is composed of two semi-ellipse cylinders cut along the prolate axis, two circular channels with the same size at the two focused points of the semi-ellipse cylinders, wherein one circular channel is provided with a photodetector with the same channel size and length. A rogue fiber, after being stripped, is put into one circular channel at one focused point of the semi-ellipse cylinder and cylindrical photoelectric detector is put into the other circular channel at the other focused point of the semi-ellipse cylinder. The highly reflective metal film coated outside the semi-ellipse cylinder can realize the full reflection of lights in the elliptical cylinder. The collection structure can effectively improve the collection efficiency of optical signal and has the advantages of simple structure, low cost, simple assembly and the like.
Description
Technical field
The present invention relates to the device in a kind of optical communication technique field, specifically is a kind of fiber Rayleigh scattering signal detector based on total reflection principle.
Background technology
For a long time, people are familiar with not enough in the fail safe of optical-fiber network.Think that traditionally optical fiber communication has good confidentiality, characteristics that antijamming capability is strong, thereby ignored safety analysis optical fiber communication.In recent years, deepen continuously along with understanding and to the research of network security, method of network attack gradually deeply, the safety problem of optical-fiber network becomes an important problem to optical device in the optical-fiber network.Because the transmission data rate of optical-fiber network is very high, the transmission rate of simple optical fiber surpasses the T bit-level, so even suffer the attack of short time also can cause mass data to be revealed, bring about great losses; The transparent characteristic of optical-fiber network is transparent equally for signal to attack and transmission signals, brings very big potential risk to network security; All there is certain potential safety hazard in some devices that use in the optical-fiber network at present, and its fail safe can not adapt to the requirement of secure communication etc.This shows, very urgent to the security attack of optical-fiber network and optical cable, defence with the technical research of eavesdropping.
The extraction of fiber middle light signal is one of key technology point of optical-fiber network attacking and defending, mainly contains access method, optical spectroscopy and contactless eavesdropping three classes at present, and three class methods all have different separately pluses and minuses:
(1), access method: promptly adopt optical fiber is inserted interception facility realization eavesdropping momently.If the time is enough short, network management device thinks that network of short duration little mistake occurs and allows light to continue transmission.Because the message transmission class in the simple optical fiber reaches the T bit-level at present, so even the eavesdropping of short time also can obtain a large amount of useful informations, thereby realize eavesdropping discontinuously.From the angle that realizes, access method is the simplest method.But this method is the original method for communicating of a kind of destruction in essence, easily is found.
(2), optical spectroscopy: promptly treat rogue fiber and specifically operate, make the light signal that transmits in the optical fiber partly leak into outer fiber, again the part light that leaks out is collected, recover the primary signal of transmitting in the optical fiber, to reach the purpose of optical cable eavesdropping.The advantage of optical spectroscopy is not destroy original data flow in the optical fiber, relatively more easily realize, and when the luminous power of leaking out in the optical fiber less than gross power 2% the time, system is difficult to discovery.Because optical spectroscopy causes the part optical power attenuation inevitably, therefore still can be detected in theory.Modal in this kind scheme is little curved method.Little curved method is to utilize fibre-optical bending to certain radius, and the light signal that transmits in the optical fiber will have part and be leaked to outer fiber, surveys this part exposed optical signal and can realize eavesdropping to optical fiber; Also can utilize the fiber clamp grip optical fiber, also have part optical signals and leak, the light signal of leakage can be recovered after collecting by the light signal that transmits in the eavesdropping optical fiber.
(3), contactless eavesdropping: promptly do not change data flow transmitted in the optical fiber, also do not change the state of optical fiber, thereby realize the eavesdropping of optical fiber.Because its " noncontact " and the characteristics of " stealing " light not from optical fiber are so this method is found least easily.Below 2 contactless eavesdroppings that can realize optical fiber: the one, treat the surreptitiously extra light of optical fiber by injecting, by the interaction of original light signal in itself and the optical fiber, infer the light signal that transmits in the former optical fiber; The 2nd, give off the Rayleigh scattering signal of optical fiber when utilizing light signal in optical fiber, to transmit, infer the light signal that transmits in the optical fiber with this, reach the purpose of information eavesdropping.The a patent EP 0915356A1 that the Herbert Walter of Deutsche Telecom submits to, US 6,265,710B1, the Rayleigh scattering signal that has proposed to utilize collection to give off silica fiber is inferred the method for signal in the optical fiber, but has the inefficient shortcoming of collection.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, a kind of fiber Rayleigh scattering signal detector is provided, can significantly improve light signal and collect efficient and can be applicable to the Rayleigh scattering signal collection structure that optical cable information is stolen.
The present invention is achieved by the following technical solutions, a kind of fiber Rayleigh scattering signal detector based on total reflection principle comprises: the oval cylinder of a quartz, described oval cylinder is made up of two semiellipse cylinders that cut along long axis direction, at two focus places of oval cylinder is two equal-sized circular channels, therein setting and channel shape in passage, photodetector that length is identical.
The length of described oval cylinder is 10～30mm.
The external wall aluminizer of described cylindroid.The purpose of the external wall plating of cylindroid highly reflecting films is the Rayleigh scattering signals that reduce to be transmitted to the cylinder outside, guarantees that as much as possible light reflects in column body, reduces the loss of light signal.
Described circular channel diameter is 130 μ m.Depend primarily on the size of photodetector.Oval cylinder is processed to two parts, and is processed into the groove (synthetic circular channel) that mates with optical fiber and detector size respectively in the position of two focus connecting lines, is beneficial to the later stage assembling.
Oval cylinder is made up of two semiellipse cylinders, a section for the treatment of rogue fiber is peelled off in the circular channel of a wherein focal position that coat is placed on oval cylinder, and in the circular channel of another focal line position the photodetector of placement garden column type.On the cross section of oval cylinder, the Rayleigh scattering signal from elliptic focus sends after oval inwall reflection, all will converge at another oval focus place, thereby realize that Rayleigh scattering signal receives.
The special light electric explorer of column type is placed on the elliptic focus position, so the Rayleigh scattering signal on this oval cross section can 100% ground be detected device and collected in theory, information transmitted lays the foundation in this optical fiber to extract for the signal processing in later stage.
Compared with prior art, the present invention has following beneficial effect:
1, testing fiber and photodetector are positioned over the bifocal place of oval cylinder respectively, the Rayleigh scattering signal that gives off in the optical fiber is in this cylindroid inner total reflection, and according to the principle of ray optics, the Rayleigh scattering signal that a focus place sends on oval cylinder cross section is necessarily collected by the photodetector at another focus place.Therefore, this collection structure can effectively improve collection efficiency of optical signal.
2, the oval cylinder that adopts quartz material to make has good biography light characteristic.
3, the metallic film of plating high reflectance on the external wall of cylindroid can effectively reduce the light signal that is transmitted to the cylinder outside, improves collection efficiency of optical signal.
4, assembling is simple between oval cylinder and testing fiber and the detector, extensibility is strong.
Description of drawings
Fig. 1 is the structural representation of fiber Rayleigh scattering signal detector.
Embodiment
Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment has provided detailed execution mode and process being to implement under the prerequisite with the technical solution of the present invention, but protection scope of the present invention is not limited to following embodiment.
As shown in Figure 1, a kind of fiber Rayleigh scattering signal detector based on total reflection principle comprises: the oval cylinder of a quartz, described oval cylinder is made up of two semiellipse cylinders 2,3 that cut along long axis direction, at two focus places of oval cylinder is two equal-sized circular channels, therein setting and channel shape in passage, photodetector 4 that length is identical.
The length of described oval cylinder is 10～30mm.
The external wall aluminizer of described cylindroid.The purpose of the external wall plating of cylindroid highly reflecting films is the Rayleigh scattering signals that reduce to be transmitted to the cylinder outside, guarantees that as much as possible light reflects in column body, reduces the loss of light signal.
Described circular channel diameter is 130 μ m.Depend primarily on the size of photodetector 4.Oval cylinder is processed to two parts, and is processed into the groove (synthetic circular channel) with optical fiber 1 and photodetector 4 size match respectively in the position of two focus connecting lines, is beneficial to the later stage assembling.
It is as follows that concrete signal is collected process: testing fiber 1 and photodetector 4 are positioned over respectively in the circular channel at bifocal place of oval cylinder, and the Rayleigh scattering signal that gives off in the optical fiber 1 is in this cylindroid inner total reflection.And according to the principle of ray optics, the Rayleigh scattering signal that a focus place sends on oval cylinder cross section is necessarily collected by the photodetector 4 at another focus place.Therefore, this collection structure can effectively improve collection efficiency of optical signal.The Rayleigh scattering signal that gives off optical fiber 1 is converted to the signal of telecommunication 5 after photodetector 4 is collected, this signal of telecommunication is further analyzed the light signal that can infer transmission in the former optical fiber 1, thereby realizes the purpose of light signal eavesdropping in the optical fiber 1.
Claims (4)
1, a kind of fiber Rayleigh scattering signal detector, it is characterized in that: the oval cylinder that comprises a quartz, described oval cylinder is made up of two semiellipse cylinders that cut along long axis direction, two focus places at oval cylinder are provided with two equal-sized circular channels, therein setting and channel shape in passage, photodetector that length is identical.
2, fiber Rayleigh scattering signal detector according to claim 1 is characterized in that, the length of described oval cylinder is 10～30mm,
3, fiber Rayleigh scattering signal detector according to claim 1 is characterized in that, the external wall aluminizer of described cylindroid.
4, fiber Rayleigh scattering signal detector according to claim 1 is characterized in that, described circular channel diameter is 130 μ m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2009100498800A CN101557257A (en) | 2009-04-23 | 2009-04-23 | Fiber Rayleigh scattering signal detector |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2009100498800A CN101557257A (en) | 2009-04-23 | 2009-04-23 | Fiber Rayleigh scattering signal detector |
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| CN101557257A true CN101557257A (en) | 2009-10-14 |
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| CNA2009100498800A Pending CN101557257A (en) | 2009-04-23 | 2009-04-23 | Fiber Rayleigh scattering signal detector |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106130723A (en) * | 2016-08-19 | 2016-11-16 | 浙江神州量子网络科技有限公司 | There is the quantum key distribution system of actively monitoring function |
| CN106442565A (en) * | 2016-10-26 | 2017-02-22 | 中国科学院上海光学精密机械研究所 | Surface defect detection apparatus with high-speed laser line scanning |
| CN113855228A (en) * | 2021-09-30 | 2021-12-31 | 杭州佳量医疗科技有限公司 | Sheath structure for ablation operation optical fiber |
-
2009
- 2009-04-23 CN CNA2009100498800A patent/CN101557257A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106130723A (en) * | 2016-08-19 | 2016-11-16 | 浙江神州量子网络科技有限公司 | There is the quantum key distribution system of actively monitoring function |
| CN106442565A (en) * | 2016-10-26 | 2017-02-22 | 中国科学院上海光学精密机械研究所 | Surface defect detection apparatus with high-speed laser line scanning |
| CN106442565B (en) * | 2016-10-26 | 2019-06-21 | 中国科学院上海光学精密机械研究所 | The surface defect detection apparatus of high-rate laser line scanning |
| CN113855228A (en) * | 2021-09-30 | 2021-12-31 | 杭州佳量医疗科技有限公司 | Sheath structure for ablation operation optical fiber |
| CN113855228B (en) * | 2021-09-30 | 2023-12-01 | 杭州佳量医疗科技有限公司 | Sheath structure for ablation operation optical fiber |
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Open date: 20091014 |