A kind of dual-polarization state analyzer for vibrating sensingTechnical field
The invention belongs to technical field of optical fiber sensing, more particularly, to a kind of dual-polarization state inspection for vibrating sensingInclined device.
Background technology
Light wave is a kind of shear wave, with polarization characteristic.Influence using vibration to optical fiber inner light beam polarization state, can surveyThe presence of fixed vibration.In the fiber polarization vibration sensing system that cost is limited, can be determined using only single analyzer and passedWhether vibration is there occurs on sense fibre circuit.But the light polarization that light source sends is varied with temperature and changed.This problem canFiber polarization can be caused to detect the fluctuation of vibration sensing system sensitivity, and then the wrong report of sensor-based system is occurred or is failed to report.AndIncrease Polarization Controller and carry out stabilized light source, the polarization state detection vibration sensing system that may be limited to cost brings by a relatively large marginCost is raised.
On the other hand in the fiber polarization vibration sensing system that cost is limited, optical signal in the non PM fiber of usePolarization state it is also more sensitive to temperature, deployment way and non PM fiber quality discrepancy.The sensitivity of single analyzer mayThere is lower vibrating sensing sensitivity in these unstable environment.Although can be become with partially stabilized environment using polarization maintaining optical fibreThe influence that change or optical fiber quality discrepancy bring, but the material cost of polarization maintaining optical fibre is too high with lower deployment cost, in the light that cost is limitedIt is difficult to be used widely in fine polarization state detection vibration sensing system.
Therefore it is current low-cost optical fiber polarization state to provide a kind of means to vibration characteristics detection in unstable polarization stateUrgent problem in detection vibration sensing system.
The content of the invention
For the disadvantages described above or Improvement requirement of prior art, the invention provides a kind of dual-polarization for vibrating sensingState analyzer, in the case where cost is not increased, offer one kind will not receive temperature, deployment way and non PM fiber poor qualityThe influence of the unstable environmental factor such as different, and with the analyzer compared with high vibration sensing sensitivity, thus solve in the prior artThe limited fiber polarization detection vibration sensing system of cost cannot the accurate change by polarization state in unstable environmentDetect the technical problem of vibration characteristics.
To achieve the above object, the invention provides a kind of dual-polarization state analyzer for vibrating sensing, including firstOptical fiber collimator, the second optical fiber collimator, the 3rd optical fiber collimator, light-splitting device, first for incident light to be divided into twoPolarizer and the second polarizer；Wherein：Incident light is raw by inciding the light-splitting device after first optical fiber collimatorInto the first light beam and the second light beam, incident first polarizer of first beam orthogonal, from the first polarizer outgoingLight by second optical fiber collimator, incident second polarizer of second beam orthogonal, from the described second polarizationThe light of piece outgoing by the 3rd optical fiber collimator, the light transmission shaft of first polarizer and the light transmission shaft of the second polarizerAngular range is 5-85 degree.
In the embodiment of the present invention, incident light is divided into by two-beam by light-splitting device, and it is incident with certain angle respectivelyTwo polarizers such that it is able to whether vibrated in detection fiber according to the light intensity sums through two polarizers.GroupOptics required for the analyzer provided into the present invention is with low cost, it is only necessary to a light-splitting device and two polarizers,And the analyzer simple structure, it is only necessary to ensure that incident light is divided into two beams and the thang-kng axle of two polarizers has certain angle,Extra analyzer need not be increased also without using polarization maintaining optical fibre, in the case where very little cost is increased, you can overcome temperature,The influence of the unstable environmental factor such as deployment way and non PM fiber quality discrepancy, and it is sensitive with being sensed compared with high vibrationDegree.So as to provide what a kind of cost of the change detection vibration characteristics that can pass through polarization state in unstable environment was limitedFiber polarization detects vibration sensing system solution.
In one embodiment of the present of invention, the angle of the light transmission shaft of first polarizer and the light transmission shaft of the second polarizerScope is 15-75 degree.
In one embodiment of the present of invention, the angle of the light transmission shaft of first polarizer and the light transmission shaft of the second polarizerIt is 45 degree.When the angle of two thang-kng axles of polarizer is 45 degree, analyzer provided in an embodiment of the present invention is by temperature, deploymentThe influence of the unstable environmental factor such as mode and non PM fiber quality discrepancy is minimum, and sensitive with highest vibrating sensingDegree.
In one embodiment of the present of invention, the light-splitting device is semi-transparent semi-reflecting lens.Semi-transparent semi-reflecting lens performance with low costIt is reliable, and need not be collimated after light splitting, it is ensured that the reliability and low cost of whole analyzer.
In one embodiment of the present of invention, the light-splitting device includes：Optical splitter or beam splitter, are arranged at the optical splitterOr beam splitter and described first states the 4th optical fiber collimator between polarizer, and be arranged at the optical splitter or beam splitter withDescribed second states the 5th optical fiber collimator between polarizer.Light-splitting device can also add two using optical splitter or beam splitterOptical fiber collimator is constituted, so as to provide more achievable scheme, has more multi-selection when device is not enough.
In one embodiment of the present of invention, the first light beam of the light-splitting device generation and the ratio of the second light beam are 50：50.When the first light beam and when being in equal proportions of the second light beam, the light intensity for inciding two polarizers are also essentially identical, it is easy to follow-upThe characteristic that optical fiber vibrates is calculated using two light intensity of polarizer are passed through.
In one embodiment of the present of invention, the minute surface of the light-splitting device is 10-80 degree with the scope of the angle of incident light.
In one embodiment of the present of invention, the minute surface of the light-splitting device and the angle of incident light are 45 degree.Work as optical splitterWhen the minute surface of part and the angle of incident light are 45 degree, the angle between the first light beam and the second light beam is 90 degree, and described first is inclinedThe angle between piece and the second polarizer that shakes is 90 degree.The space of each optics sets in convenient dual-polarization state analyzer of the present inventionPut, also allow for later use through two light intensity of polarizer to calculate the characteristic that optical fiber vibrates.
In one embodiment of the present of invention, incident light incides the light-splitting device by non PM fiber.By this hairThe dual-polarization state analyzer that bright embodiment is provided, it is not necessary in the optical path using polarization maintaining optical fibre, using common non PM fiber,The influence of the unstable environmental factors such as temperature, deployment way and non PM fiber quality discrepancy can be overcome, with compared with Gao ZhenDynamic sensing sensitivity.
In one embodiment of the present of invention, incident light incides the light-splitting device by single-mode fiber or multimode fibre.By dual-polarization state analyzer provided in an embodiment of the present invention, in its each light path as needed both can be used single-mode fiber orMultimode fibre can be used such that it is able to the vibration detection of all kinds optical fiber is applied to, with wide application scenarios.
Brief description of the drawings
Fig. 1 is a kind of structural representation of dual-polarization state analyzer for vibrating sensing in the embodiment of the present invention；
Fig. 2 is the logical angle of optical axis schematic diagram of two polarizers in the embodiment of the present invention；
Fig. 3 is the structural representation of another dual-polarization state analyzer for vibrating sensing in the embodiment of the present invention；
Fig. 4 is the structural representation of another dual-polarization state analyzer for vibrating sensing in the embodiment of the present invention；
Fig. 5 is a kind of shell mechanism schematic diagram of dual-polarization state analyzer for vibrating sensing in the embodiment of the present invention；
In all of the figs, identical reference be used for represent identical element or structure, wherein：
The optical fiber collimator 4- light-splitting devices 5- first of 1- the first optical fiber collimator the second optical fiber collimators of 2- 3- the 3rdThe optical fiber collimators of the 4th optical fiber collimator 8- of polarizer 6- the second polarizer 7- the 5th.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and ExamplesThe present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, andIt is not used in the restriction present invention.As long as additionally, technical characteristic involved in invention described below each implementation methodNot constituting conflict each other can just be mutually combined.
As shown in figure 1, the invention provides a kind of dual-polarization state analyzer for vibrating sensing, including including the first lightFine collimater 1, the second optical fiber collimator 2, the 3rd optical fiber collimator 3, light-splitting device 4, for incident light to be divided into twoOne polarizer 5 and the second polarizer 6；Wherein：Incident light after first optical fiber collimator 1 by inciding the optical splitterPart 4, generates the first light beam and the second light beam, incident first polarizer 5 of first beam orthogonal, from the described first polarizationThe light of the outgoing of piece 5 by second optical fiber collimator 2, incident second polarizer 6 of second beam orthogonal, from describedThe light of the outgoing of the second polarizer 6 is by the 3rd optical fiber collimator 3, the light transmission shaft of first polarizer 5 and the second polarizationThe light transmission shaft of piece 6 forms an angle α.
Optical fiber collimator, is generally accurately positioned with GRIN Lens by tail optical fiber and formed.It can be by the transmission light in optical fiberIt is transformed into collimated light (directional light), or extraneous parallel (less parallel) is optically coupled in single-mode fiber.
When incident light by the first optical fiber collimator 1 collimate after, then by the light-splitting device 4 be divided into two generation two beamsLight.Incident thang-kng axle has first polarizer 5 and the second polarizer 6 of certain angle to two-beam respectively, can to by this twoThe judgment basis that the absolute value summation of the light intensity of individual polarizer is vibrated as optical fiber.
Between two angles of polarizer should spend 0 to 90.As shown in Fig. 2 the span of the angle α is 5-85Degree.Preferably, the span of the α is 15-75 degree.It is experimentally confirmed, when the value of the α is 45 degree, by twoThe light intensity absolute value sum of individual polarizer is least sensitive to ambient noises such as temperature, deployment way and optical fiber quality discrepancies.Therefore,It is optimal value when angle between the thang-kng axle of the polarizer 6 of first polarizer 5 and second is 45 degree.
Wherein, the light-splitting device 4 can be semi-transparent semi-reflecting lens.Incident light is by forming reflection after the semi-transparent semi-reflecting lensLight and transmitted light two-beam, the incident polarizer 6 of first polarizer 5 and second of difference.
Or the light-splitting device 4 can be optical splitter or beam splitter, now need in optical splitter or beam splitter and twoOne optical fiber collimator is respectively set between polarizer.As shown in figure 3, the light-splitting device 4 can include：Optical splitter or beam splittingDevice, is arranged at the optical splitter or beam splitter and the described first the 4th optical fiber collimator 7 stated between polarizer, and be arranged atThe optical splitter or beam splitter and described second state the 5th optical fiber collimator 8 between polarizer.
The effect of the light-splitting device 4 is that incident light is divided into two to form the first light beam and the second light beam, described firstThe ratio of light beam and the second light beam can determine as needed.Preferably, the ratio of first light beam and the second light beam is 50：50.Now, reflected light and transmitted light, incident light for example are formed by semi-transparent semi-reflecting lens when light-splitting device 4 is semi-transparent semi-reflecting lensHalf light intensity reflected, half is transmitted.
The light-splitting device 4 need to realize being divided into two for incident light, so the minute surface of the light-splitting device 4 will with incident lightShape forms an angle.The scope of the usual angle is 10-80 degree (being illustrated with acute angle).Preferably, as shown in figure 1, in this hairIn bright one embodiment, the minute surface of the light-splitting device 4 and the angle of incident light are 45 degree.Now, the first light beam and secondAngle between light beam is 90 degree, and the angle between the polarizer 6 of first polarizer 5 and second is 90 degree.
In addition, as shown in figure 4, in another embodiment of the present invention, minute surface and the incident light of the light-splitting device 4Angle is 30 degree.Now, the angle between the first light beam and the second light beam is 60 degree, and first polarizer 5 and second is polarizedAngle between piece 6 is 120 degree.I.e. described first polarizer 5 is symmetrical with the minute surface of the light-splitting device 4 with the second polarizer 6Distribution.
In one embodiment of the invention, the incident light generally incides the light-splitting device by non PM fiber4.It is of course also possible to use polarization maintaining optical fibre.
In one embodiment of the invention, incident light incides the light-splitting device by single-mode fiber or multimode fibre4.When using dual-polarization state analyzer provided in an embodiment of the present invention, the optical fiber used in each light path may each be single-mode fiberOr multimode fibre, can determine as needed.
A kind of shell mechanism schematic diagram of dual-polarization state analyzer in the embodiment of the present invention is illustrated in figure 5, it is accurate by optical fiberThe light channel structure that straight device, light-splitting device and polarizer are constituted is packaged in shell mechanism, formed can direct engineer applied analyzingDevice.
As it will be easily appreciated by one skilled in the art that the foregoing is only presently preferred embodiments of the present invention, it is not used toThe limitation present invention, all any modification, equivalent and improvement made within the spirit and principles in the present invention etc., all should includeWithin protection scope of the present invention.