CN1460870A - All optical fibre interference method and its testing system - Google Patents
All optical fibre interference method and its testing system Download PDFInfo
- Publication number
- CN1460870A CN1460870A CN 03129218 CN03129218A CN1460870A CN 1460870 A CN1460870 A CN 1460870A CN 03129218 CN03129218 CN 03129218 CN 03129218 A CN03129218 A CN 03129218A CN 1460870 A CN1460870 A CN 1460870A
- Authority
- CN
- China
- Prior art keywords
- light
- fiber
- signal
- interference
- disturbing source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The present invention relates to an all optical fibre interference method and its system. Said system can implement the test of vibration characteristics, modutation of externally-added electric signal and optical switch function, and said system is formed from optical path, coupler, light source, optical fiber delay line and dither source, finally the optical signal of beam with dither source can be absorbed by detector in the coupler. Said invention can be extensively used in the fields of vibration test, communication, sonar detection and speech signal transmission.
Description
Technical field
The present invention is new full optical fiber interference method and test macro thereof.
Background technology
Interference of light has been widely used in the test and the communications field, traditional interference of light method depends on the coherent length of laser and complicated light path structure (often adopting prism, lens and beam splitter) and debugging, and its structure mainly contains: Michelson, Mach increase Dare and Fabry-Perot.Along with the maturation of development of fiber technology and photoelectric device, the fiber optic interferometric technology is developed in eighties of last century, but its structure and principle of work and traditional laser interference method are as broad as long.The full light fiber white light interference method is in eighties of last century late nineteen nineties appearance, and its structure mainly depends on many (more than two or two) fiber couplers and is combined into optical interference circuit, and is mainly used in sensory field of optic fibre.Therefore there is complex structure in prior art, inconvenient debugging, the limited deficiency that waits of application.
Summary of the invention
The method for designing and the test macro thereof that the purpose of this invention is to provide a kind of convenience, succinct, all-fiber interferometer that application is wide.
The full optical fiber interference method that the present invention proposes, the light that is sent by light source is coupled and forms clockwise after the device beam splitting and the two-way light of transmission counterclockwise, and under the situation that fibre delay line exists, two light beams are by the asynchronism(-nization) of disturbing source, corresponding disturbing signal is also inequality, and can be expressed as time delay:
C is the light velocity in the vacuum, and L postpones fiber lengths, n
EffBe the equivalent refractive index of optical fiber, the light path refractive index n that disturbing source forms two-beam
sWith geometrical length L
sProduct, can represent A (t) and A (t-τ),
A(t)＝n
s(t)L
s(t) (2)
A(t-τ)＝n
s(t-τ)L
s(t-τ) (3)
Because remove the influence of disturbing source, the transmission light path that two light beams pass through is equal fully, so the optical path difference Δ L that two light beams form can be expressed as:
ΔL＝A(t)-A(t-τ) (4)
For the fiber-optic vibration test macro, disturbing source is corresponding to vibration displacement, i.e. A (t)～S (t), and light does not change in time by the refractive index of disturbing source, so formula (4) can be expressed as
ΔL＝n
s[S(t)-S(t-τ)] (5)
Utilize mean value theorem, following formula can be rewritten as
ΔL＝n
sS′(t-τ/2)τ (6)
Following formula corresponding to the phase place (t) of interference light is
In the optical communication field modulating system, disturbing source is corresponding to crystal refractive index, i.e. A (t)～n (t), light are during by disturbing source, and the geometric distance of transmission light remains unchanged, so formula (4) can be expressed as
ΔL＝L
s[n(t)-n(t-τ)] (8)
Modulation signal m (t) can be expressed as with the relation of refractive index n (t):
n(t)＝f[m(t)] (9)
Utilize mean value theorem, following formula can be rewritten as
ΔL＝L
sf′[m(t)]τ (10)
Following formula corresponding to the phase place (t) of interference light is
The interference pattern of utilization 3 * 3 fiber couplers, at the detectable signal output terminal, interference signal can be expressed as respectively:
I
1(t)＝I
0cos[(t)+
0] (12)
I
2(t)＝I
0cos[(t)-
0] (13)
In splitting ratio is 13 * 3 fiber couplers,
0=120 degree; If the splitting ratio of coupling mechanism is not 1, initial phase
0≠ 120 degree.(12) the interference signal amplitude peak in (13) formula is not equating; Above in two formulas,
0Be the initial phase of interference signal, in vibration test system and voice signal transmission system, (t) is shown in (7) formula; In the optical modulation and photoswitch application of fiber optic communication field, (t) is shown in (11) formula; Because initial phase is different, it is 0 that one tunnel light intensity will appear in two interference signals, and another road light intensity is not 0 situation, and promptly all-fiber interferometer shows the switching function to light.
Can provide a kind of system that can be widely used in Fibre Optical Sensor and optical fiber communication according to the inventive method, system adopts a fiber coupler to realize the white light interference method, and this system not only can be applied to sensory field of optic fibre, can also be applied to fiber optic communication field.With the structure among Fig. 1 is example, the light that stabilized light source sends connects through wire jumper FC/PC, enter 2 * 2 fiber couplers, after beam split, clockwise be transferred to port (8) through disturbing source (4) from the light of the port (7) of coupling mechanism after through fibre delay line (3), the light of port (8) then is transferred to port (7) by fibre delay line (3) counterclockwise by disturbing source (4) earlier.Two light beams form the light signal that carries the disturbing source physical features in fiber coupler (2), be detected device (6) and receive.By the inverting interference signal, finally obtain the physical characteristics of disturbing source (4) by formula (12) (13).
In structure shown in Figure 2, the light that stable light source (1) sends after beam split, through disturbing source (4) clockwise is transferred to port (8) behind the light of port (7) the process fibre delay line (3) through fiber coupler (2); The light of port (8) is transferred to port (7) by disturbing source (4) back by fibre delay line (3) inhour earlier.Two light beams form the light signal that carries the disturbing source physical features in 3 * 3 fiber couplers (2), be detected device (5), (6) reception.By the inverting interference signal, finally obtain the physical characteristics of disturbing source (4).
Fig. 1 and structure shown in Figure 2, its principle of work is the same with method, and what just Fig. 1 obtained is not have initial phase difference
0Interference signal.
According to (7) and (11) formula, as can be seen, the interferometric phase size is directly proportional with optical fiber time τ, promptly is directly proportional with fibre delay line length.According to these characteristics,, can increase the effect that fibre delay line length reaches increases modulation amplitude for little disturbing signal; For big modulation signal, can adopt the method that reduces fibre delay line length, reduce requirement to the signal acquiring system frequency bandwidth.Can adjust the phase modulation radian as the case may be, be a distinguishing feature of the present invention.
All-fiber interferometer of the present invention, connected mode between being connected of fiber coupler and optical fiber, the optical fiber is that the mode of fusing connects, light source is connected with the connected mode FC/PC wire jumper of interference system, and interference system also is that the FC/PC wire jumper is connected with the connected mode of detector.
Disturbing source of the present invention is the device that changes in time of light path that makes transmission light, therefore, can be vibrating device, for example the vibration that produces such as loudspeaker, shaking platform, bridge machinery etc.; Perhaps light by the time, the crystal that optical fibre refractivity can change with the impressed voltage signal is as lithium columbate crystal etc.
The fiber coupler of system of the present invention is tapered fiber coupler.
The luminous power of coupling mechanism is divided equally, and promptly 3 * 3 fiber coupler luminous power splitting ratios are 1: 1: 1, and 2 * 2 fiber coupler luminous power splitting ratios are 1: 1.
Single-mode fiber, multimode optical fiber all are applicable to system of the present invention.
Stabilized light source can be any in following: operation wavelength is the semiconductor laser diode (LD) of 1.31 μ m or 1.55 μ m; Semiconductor light-emitting-diode (LED) laser instrument; Super-radiance light emitting diode (SLD) laser instrument etc.
The outstanding advantage of the inventive method is to have changed the defective that the interference of light in the past must depend on laser (narrow spectrum) light source, can not only be applied to the interference of laser, can also be applied to the interference of broad spectrum light source; Simultaneously, this interference technique can also realize the laser external modulation to electric signal, also can realize distribution adjusted and light switch function to light intensity, will be applied to the external modulation and the full optical routing exchange network of light signal; System can adjust easily to the measurement sensitivity of disturbing source, can be applicable to the test in strong disturbance source, also can be applicable to the test in weak disturbance source; System is not subjected to the restriction of disturbance source frequency, and frequency is only relevant with the response of photodetector, and there is not the frequency response problem in light path system.The present invention can access the interference signal that two-way has fixed skew, will improve the sensitivity and the precision of system.Interference system of the present invention, simple in structure, debugging is convenient, sensitivity and precision height.
Description of drawings
Fig. 1 is the present invention's 2 * 2 coupler system structural representations.
Fig. 2 is the structural representation of the present invention's 3 * 3 coupler systems.The 1st, stabilized light source, the 2nd, fiber coupler, the 3rd, fibre delay line, the 4th, disturbing source, the 5, the 6th, photodetector, the 7, the 8th, two ports of fiber coupler.
Fig. 3 is a fibre delay line length when being 8.5Km, to telephone bell during as disturbing source, and the interference curve figure of the generation of all-fiber interferometer.
Embodiment
Embodiment
In the present embodiment, used laser instrument is SO3-B type super radiation light emitting tube (SLD) the type stabilized light source (1) that 44 research institutes of main office of electronics group produce.Fiber coupler (2) is the single-mode optical-fibre coupler that Wuhan post and telecommunications research institute produces.Photodetector (6) is that 44 models of being produced are the InGaAs photodetector of GT322C500.Used optical fiber is " healthy and free from worry " G652 type single-mode fiber produced in USA.The telephone set that produces the sound wave disturbance is the HWCD786 of Amoisonic (a 6) P/TSD telephone set (4).Connect pale pinkish purple device, optical fiber, fibre delay line by Fig. 1 mode with the mode of fusing.Light source is that the FC/PC wire jumper is connected with interference system, interference system with the connected mode of detector.The port of 2 * 2 fiber couplers is (7) (8).The results are shown in Figure 3 with this system testing, this interference curve is described by formula (12), (13), and expression is to the test result of voice signal disturbing source.
Claims (9)
1. full optical fiber interference method, it is characterized in that being coupled and form after the device beam splitting clockwise and the two-way light of transmission counterclockwise by the light that light source sends, under the situation that fibre delay line exists, two light beams are by the asynchronism(-nization) of disturbing source, corresponding disturbing signal is also inequality, and can be expressed as time delay:
C is the light velocity in the vacuum, and L postpones fiber lengths, n
EffBe the equivalent refractive index of optical fiber,
The light path refractive index n that disturbing source forms two-beam
sWith geometrical length L
sProduct, can represent A (t) and A (t-τ),
A(t)＝n
s(t)L
s(t) (2)
A(t-τ)＝n
s(t-τ)L
s(t-τ) (3)
Because remove the influence of disturbing source, the transmission light path that two light beams pass through is equal fully, so the optical path difference Δ L that two light beams form can be expressed as:
ΔL＝A(t)-A(t-τ) (4)
For the fiber-optic vibration test macro, disturbing source is corresponding to vibration displacement, i.e. A (t)～S (t), and light does not change in time by the refractive index of disturbing source, so formula (4) can be expressed as
ΔL＝n
s[S(t)-S(t-τ)] (5)
Utilize mean value theorem, following formula can be rewritten as
ΔL＝n
sS′(t-τ/2)τ (6)
Following formula corresponding to the phase place (t) of interference light is
In the optical communication field modulating system, disturbing source is corresponding to crystal refractive index, i.e. A (t)～n (t), light are during by disturbing source, and the geometric distance of transmission light remains unchanged, so formula (4) can be expressed as
ΔL＝L
s[n(t)-n(t-τ)] (8)
Modulation signal m (t) can be expressed as with the relation of refractive index n (t):
n(t)＝f[m(t)] (9)
Utilize mean value theorem, following formula can be rewritten as
ΔL＝L
sf′[m(t)]τ (10)
Following formula corresponding to the phase place (t) of interference light is
The interference pattern of utilization 3 * 3 fiber couplers, at the detectable signal output terminal, interference signal can be expressed as respectively:
I
1(t)＝I
0cos[t)+
0] (12)
I
2(t)＝I
0cos[(t)-
0] (13)
In splitting ratio is 13 * 3 fiber couplers,
0=120 degree; If the splitting ratio of coupling mechanism is not 1, initial phase
0≠ 120 degree.(12) the interference signal amplitude peak in (13) formula is not equating; Above in two formulas,
0Be the initial phase of interference signal, in vibration test system and voice signal transmission system, t) be shown in (7) formula; In the optical modulation and photoswitch application of fiber optic communication field, (t) is shown in (11) formula; Because initial phase is different, it is 0 that one tunnel light intensity will appear in two interference signals, and another road light intensity is not 0 situation, and promptly all-fiber interferometer shows the switching function to light.
2. all-fiber interferometer according to claim 1, the light path that it is characterized in that this system is as follows: light source (1) is fiber coupler (2) afterwards, after light is coupled the device beam split, be transferred to port (8) clockwise through disturbing source (4) behind the light of port (7) the process fibre delay line (3); The light of port (g) is transferred to port (7) by disturbing source (4) back by fibre delay line (3) inhour earlier; Two light beams form the light signal that carries the disturbing source physical features in 2 * 2 fiber couplers (2), this signal is detected device (6) and receives, and by the inverting interference signal, are obtained the physical characteristics of disturbing source (4) by formula (12) (13).
3. according to the described all-fiber interferometer of claim 2, it is characterized in that two light beams form the light signal that carries the disturbing source physical features in 3 * 3 fiber couplers (2), this interference light signal is by two detectors, and promptly detector (5), detector (6) receive and detect.
4. all-fiber interferometer according to claim 2 is characterized in that the connected mode between being connected of coupling mechanism and optical fiber, the optical fiber is that the mode of fusing connects, and being connected of light source and optical fiber, detector adopt wire jumper to connect with being connected of optical fiber.
5, all-fiber interferometer according to claim 2 is characterized in that disturbing source is a vibrating device, or the optical fibre refractivity crystal that can change with the impressed voltage signal, or the shock wave sniffer.
6. according to claim 2 or 3 described all-fiber interferometers, it is characterized in that fiber coupler is tapered fiber coupler.
7. all-fiber interferometer according to claim 6, the luminous power that it is characterized in that fiber coupler is to divide equally.
8. all-fiber interferometer according to claim 2 is characterized in that used optical fiber or fibre delay line can be single-mode fibers, or multimode optical fiber.
9. all-fiber interferometer according to claim 2 is characterized in that used laser works wavelength is semiconductor laser diode or the semiconductor light-emitting-diode laser instrument of 1.31 μ m or 1.55 μ m, perhaps super-radiance light emitting diode laser instrument.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03129218 CN1460870A (en) | 2003-06-12 | 2003-06-12 | All optical fibre interference method and its testing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03129218 CN1460870A (en) | 2003-06-12 | 2003-06-12 | All optical fibre interference method and its testing system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1460870A true CN1460870A (en) | 2003-12-10 |
Family
ID=29591179
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03129218 Pending CN1460870A (en) | 2003-06-12 | 2003-06-12 | All optical fibre interference method and its testing system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1460870A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100547365C (en) * | 2008-05-09 | 2009-10-07 | 东南大学 | The wide-field full-optical fiber perturbation sensing system high sensitivity perturbation detecting light path device |
| CN102157044A (en) * | 2011-04-07 | 2011-08-17 | 杨峰 | Full-optical fiber system for locating and alarming |
| CN102607602A (en) * | 2012-03-30 | 2012-07-25 | 苏州攀星光电科技有限公司 | Optoelectronic system for measuring optical fiber interference signal |
| CN102620758A (en) * | 2012-03-30 | 2012-08-01 | 苏州攀星光电科技有限公司 | White light interference sensing system |
| CN102620759A (en) * | 2012-03-30 | 2012-08-01 | 苏州攀星光电科技有限公司 | White light interference photoelectric system |
| CN107152913A (en) * | 2016-03-04 | 2017-09-12 | 横河电机株式会社 | Vibration displacement determines device and vibration displacement assay method |
| CN113358142A (en) * | 2021-05-21 | 2021-09-07 | 复旦大学 | Optical fiber interference light path based on optical unidirectional transmission and construction method thereof |
-
2003
- 2003-06-12 CN CN 03129218 patent/CN1460870A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100547365C (en) * | 2008-05-09 | 2009-10-07 | 东南大学 | The wide-field full-optical fiber perturbation sensing system high sensitivity perturbation detecting light path device |
| CN102157044A (en) * | 2011-04-07 | 2011-08-17 | 杨峰 | Full-optical fiber system for locating and alarming |
| CN102157044B (en) * | 2011-04-07 | 2013-06-12 | 杨峰 | Full-optical fiber system for locating and alarming |
| CN102607602A (en) * | 2012-03-30 | 2012-07-25 | 苏州攀星光电科技有限公司 | Optoelectronic system for measuring optical fiber interference signal |
| CN102620758A (en) * | 2012-03-30 | 2012-08-01 | 苏州攀星光电科技有限公司 | White light interference sensing system |
| CN102620759A (en) * | 2012-03-30 | 2012-08-01 | 苏州攀星光电科技有限公司 | White light interference photoelectric system |
| CN107152913A (en) * | 2016-03-04 | 2017-09-12 | 横河电机株式会社 | Vibration displacement determines device and vibration displacement assay method |
| CN113358142A (en) * | 2021-05-21 | 2021-09-07 | 复旦大学 | Optical fiber interference light path based on optical unidirectional transmission and construction method thereof |
| CN113358142B (en) * | 2021-05-21 | 2022-11-18 | 复旦大学 | Optical fiber interference light path based on optical unidirectional transmission and construction method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5268741A (en) | Method and apparatus for calibrating a polarization independent optical coherence domain reflectometer | |
| AU747525B2 (en) | Apparatus and method for monitoring a structure using a counter-propagating signal method for locating events | |
| CN104703105B (en) | Double FP chambers optical fiber sound sensing probes and its sensor-based system | |
| KR101000974B1 (en) | Measurement Method of Chromatic Dispersion of Optical Beam Waveguide Using Interference Fringe Measurement system | |
| CN102538845B (en) | Multi-point disturbance location method | |
| CN110726468B (en) | Distributed optical fiber acoustic wave sensing system based on straight waveguide phase modulator | |
| CN103411542A (en) | Optical fiber micrometric displacement sensor based on Mach-Zehnder interference and manufacturing method of optical micrometric displacement sensor | |
| CN112033523A (en) | Optical fiber distributed disturbance sensing system based on double Michelson interferometers | |
| CN1238041A (en) | Integrated interferometer | |
| CN111308125B (en) | Acceleration detection method based on optical fiber Sagnac interferometer and acceleration meter | |
| CN1460870A (en) | All optical fibre interference method and its testing system | |
| CN102095434A (en) | Reflection type full optical fiber interference system | |
| CN2513077Y (en) | Interference type optic fibre length measurer | |
| Sun et al. | Distributed disturbance sensor based on a novel Mach-Zehnder interferometer with a fiber-loop | |
| CN1236336C (en) | Full optical fiber interference method formed by feedback loop and measuring system thereof | |
| CN2625862Y (en) | Full optical fiber vibration measurement apparatus | |
| CN1588144A (en) | Full optical fiber interference system | |
| CN114018390A (en) | Acceleration measuring device | |
| CN1558189A (en) | Full optical fiber positioning and testing method for strain and vibration | |
| CN2669197Y (en) | Multi-mode fully-optical-fiber speed measuring apparatus | |
| JP3287441B2 (en) | Optical component for optical line identification and remote measuring method and device therefor | |
| CN1641318A (en) | Optical fiber sensor based on laser feedback | |
| CN100427905C (en) | All-optical fiber spectral measurement method | |
| CN117308807B (en) | Vector bending sensor based on multi-core optical fiber | |
| Wang et al. | An in-fiber Acceleration Sensor based on Fabry–Perot Cavity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |