AU2020103490A4 - A multiplexing optical fiber interferometer and its nesting construction method - Google Patents
A multiplexing optical fiber interferometer and its nesting construction method Download PDFInfo
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
- G02B6/29358—Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02049—Interferometers characterised by particular mechanical design details
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
- G02B6/29349—Michelson or Michelson/Gires-Tournois configuration, i.e. based on splitting and interferometrically combining relatively delayed signals at a single beamsplitter
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
- G02B6/29358—Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator
- G02B6/29359—Cavity formed by light guide ends, e.g. fibre Fabry Pérot [FFP]
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12133—Functions
- G02B2006/12159—Interferometer
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The present invention belongs to the field of optical fiber technology, and specifically relates to a
fiber interferometer based on the principle of space division multiplexing (SDM). The present
invention is based on the principle of SDM, in a white light fiber interferometer, embedding a
fiber splitter and an optical path step accumulating-type optical delay line to construct a plurality
of white light fiber interferometers based on multiplexing techniques, this can realize the nesting
and multiplexing of the fiber interferometers. The purpose of the present invention is to solve the
multiplexing problems of optical fiber interferometers, so that when optical fiber interferometers
are used for the measurement of deformation, strain, temperature, pressure and other physical
quantities, without affecting each other, they can share an optical demodulation system,
improving the reliability of measurement, reducing the cost of a single point of measurement,
and realizing the arraying and networking of sensors.
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Description
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A multiplexing optical fiber interferometer and its nesting construction method
[0001] The invention belongs to the optical fiber technology field, it relates to an optical fiber
interferometer based on the principle of space division multiplexing (SDM) and its nesting
construction method.
[0002] Optical fiber interferometers that employ low coherence, broad spectrum light sources
such as light emitting diodes (LEDs), amplified spontaneous emissions (ASEs), or multimode
laser diodes are commonly referred to as white light fiber interferometers. Compared with other
optical fiber interferometers, in addition to high sensitivity, intrinsically safe, anti
electromagnetic interference and other advantages, the most important feature is that the absolute
measurement on measures to be tested such as pressure, strain, and temperature, is widely used
in physical, mechanical, environmental, chemical and biomedical measurement.
[0003] One of the problems encountered in the actual measurement and testing applications of
white light optical fiber interferometer is how to measure in real-time of the multi-point position distribution of physical quantities, such as during the non-destructive testing and monitoring of large structures or critical areas (hydroelectric power stations, dams, bridges, etc.) to determine their safety conditions, the need to implant sensors in critical areas to build a monitoring network, then perform real-time and online extraction on information such as the internal displacement, deformation, strain, and temperature, the number of sensors are usually dozens or hundreds of. The sensing of a single location or a single physical quantity is far from satisfying the requirements of people to acquire the whole thing or the system state. Therefore, the development of optical fiber interferometer multiplexing technology, under the premise of mutual non-influence, the use of the same measurement optical path to achieve the interrogation and searching of multiple interferometers (sensors) measurement information will greatly simplify the complexity of the system and reduce the cost of testing, and this can ensure real time test system and improve the reliability of measurement.
[0004] In order to solve the problem of multiplexing of optical fiber interferometers, people have
carried out a variety of research, multiplexing technologies that have been developed are: time
division multiplexing (TDM), frequency division multiplexing (FDM or FMCW), wavelength
division multiplexing (WDM) and SDM.
[0005] Jackson, et al. (Santos, J.L., Jackson, D.A., Coherence sensing of time-addressed optical
fiber sensors illuminated by a multimode laser diode Appl. Opti, 30, 5068-5076, 1991) has
developed TDM, it is a multiplexing technique that takes advantage of the optical path difference
of the sensing units on the same optical fiber bus, i.e., this is a multiplexing technique for address
by using the delay effect of optical fibers on the light waves. The technical solution is as follows:
The light pulse emitted by the multimode laser diode is less than the transmission time between
the neighboring sensors on the optical fiber bus, it is injected into the input of the optical fiber
bus, due to the different distances between the sensor units on the bus and the transmitting end of
the light pulse, a series of pulses will be received at the end of the optical fiber bus, and the delay
size of the optical pulse reflects the address distribution of the sensing unit. The sensor
information can be obtained if the white light sensor is scanned continuously over the width of the optical pulse. This method is complex, with limited multiplexing numbers, small measurement range and low accuracy.
[0006] Liu, et al. (T.Liu, G.F.Fernando, A frequency division multiplexed low-finesse optical fiber Fabry-Perot sensor system for strain and displacement measurements, Review of Scientific Instruments, 71(3), 1275-1278, 2000) developed the FDM technology, which directly measures the multiplied results of optical spectrum output by multiple Fabry-Perot interferometers with different cavity lengths using a spectral analyzer, and use mathematical transformation of the wavelength domain into the frequency domain to obtain the cavity lengths of the Fabry-Perot interferometers. This method is limited by the cavities and cavity length differences, and the number of interferometers to be multiplexed is limited to a few.
[0007] Yunjiang Rao, et al. (C.X.Zhou, Yun-Jiang Rao, and Jian Jiang, A coarse wavelength division-multiplexed extrinsic fiber Fabry-Perot sensor system, Proc.SPIE 5634, 219(2005)) developed WDM, which uses coarse wavelength division multiplexer (CWDM) to divide the broadband light source into multiple channels for the multiplexing of the optical fiber interferometers. For example, for a 1x4CWDM, the wavelength range can be divided into 1521 1601nm broadband light uniformly decomposed into four wavelength channels, namely, 1521 1541nm, 1541-1561nm, 1561-1581nm, 1581-1601nm, each channel connects to a sensor to achieve the WDM of four sensors. This multiplexing technique has the advantages of simple structure and high measurement accuracy, but it is limited by the bandwidth of the light source and the spectral range of the spectral analysis instrument, which limits the number of sensors to be multiplexed, and generally the number of multiplexed sensors is limited to 10.
[0008] The above-mentioned multiplexing methods of optical fiber interferometer are mainly based on TDM, FDM, WDM and other techniques, and a large number of technical patents and technical papers have been published. For example, the application (patent) No. 200310104081.1 for the optical amplification-based optical fiber Fizeau strain sensor frequency division multiplexing system and method (the invention patent of Yunjiang Rao and Jian Jiang) published in the Chinese Patent Application Publication.
[0009] It is an object of the present invention to propose a nested construction method of an
optical fiber interferometer based on the principle of SDM to solve the problem of low
multiplexing number and complex structure of optical fiber interferometers without mutual
influence, and an all-optical fiber interferometer with an optical fiber sensor array constructed
therefrom.
[0010] The object of the invention is realized by:
[0011] 1. A multiplexing optical fiber interferometer, it comprises a broad spectrum light source
1 and a photodetector 2. The broad spectrum light source 1 and the photodetector 2 are
connected to two optical fiber inputs of an optical fiber 2x2 coupler 3, the two optical fiber
outputs of the optical fiber 2x2 coupler 3 are connected to an optical fiber splitter 6 and an
optical path step accumulating-type optical delay line 7 via single-mode fibers 4 and 5, the
optical path step accumulating-type optical delay line 7 is connected to a continuously variable
optical delay line 8, and the optical fiber splitter 6 is connected to a nest-multiplex optical fiber
interferometer array 9.
[0012] 2. A nesting construction method of a multiplexing optical fiber interferometer. The
broad spectrum light emitted from the light source is split by the fiber splitter, enters the
measurement optical path of the nest-multiplex fiber interferometer and become the
measurement light beam. Using the accumulated optical paths resulted from the reference light beam transmitting back and forth many times in the optical path step accumulating-type optical delay line, and match with the optical path received by the measurement light beam in the nest multiplex interferometer measuring optical path, to achieve white light interference strips.
[0013] The invention also has the following structural characteristics:
[0014] 1. The fiber 2x2 coupler 3 is a 3dB optical fiber 2x2 coupler.
[0015] 2. The fiber splitter is a single mode optical fiber patchcord.
[0016] 3. The optical fiber splitter is a 1xN star-type optical fiber coupler.
[0017] 4. The optical fiber splitter is a 1xN optical fiber switch.
[0018] 5. The optical path step accumulating-type optical delay line is a single mode optical fiber
patchcord.
[0019] 6. The optical path step accumulating-type optical delay line is a multi-path fiber switch
connected with different lengths of single-mode fibers.
[0020] 7. Optical path step accumulating-type optical delay line is an optical fiber Fabry-Perot
resonant cavity or an optical fiber circular resonant cavity.
[0021] The basic principle of the invented method is the principle of SDM, as shown in FIG. 1 the Michelson interferometer, the broad spectrum light emitted by the light source 1 enters into the single-mode fiber, is split into two beams by the 3dB single-mode fiber 2x2 coupler 3, a beam of light enters into the single-mode connection fiber 4 as a measurement arm and enters into the multiplexing optical fiber interferometer array 9 connected by the optical fiber splitter 6, then it is reflected by the optical reflective surface of the array and returns through the optical fiber splitter 6, the connection fiber 4, the coupler 3 back to the photodetector 2, this beam of light is called the measurement signal light. Another light from the 3dB single-mode fiber 2x2 coupler 3 emitted from the light source enters the single-mode connection fiber 5, which acts as a reference arm, and the optical path step accumulating-type optical delay line 7, then it is reflected by the continuously variable optical delay line 8 and returns via the optical path step accumulating-type optical delay line 7, the connection fiber 5, the coupler 3, and the photodetector 2, and is called the reference signal light. The measurement signal light and the reference signal light are coherent-superposed on the surface of the detector, since the coherence length of a broad spectrum light source is very short, ranging from a few micrometers to tens of micrometers, only when the optical path difference between the reference and measurement signal light is smaller than the coherence length of the light source, coherence superposition will occur and a white interferogram will be output. The intensity of the interfering strips can be expressed as follows:
I=I+I2+2 ''I,2. (x)l.cos(k.x+#) (1)
In the formula, Ii and 12 are the signal intensity of the reference light beam and the measurement light beam, k is the wavenumber, x is the optical path difference of the two interference signals, (p is the initial phase, and y(x) is the autocorrelation function of light source
[0022] The white light interferometric strips are characterized by a central strip with one main maximum, which corresponds to the position of zero optical path difference, i.e., when the reference beam and the measurement beam have equal optical path, then the reference beam and the measurement beam have a matching optical path relationship. The central interferometric strip can be obtained by changing the delay amount of the optical delay line to vary the optical path of the reference signal. The center strip position provides a reliable absolute position reference, when the optical path of the measurement beam changes due to the influence of the external physical quantity to be measured, the absolute value of the measured quantity can be obtained simply by the white interferometric strip position change obtained by scanning the reference arm optical path.
[0023] Since the interference phenomenon of optical interferometer using a broad spectrum light
source only occurs within the coherence length, which corresponds to a few micrometers to tens
of micrometers near the optical path matching conditions, if multiple fiber interferometers are
nested in series, parallel or series-parallel complexes, so that the interference signals
corresponding to different fiber interferometers are separated from each other in the optical path
scanning space, the multiplexing of optical interferometers can be realized. Since this technique
makes both the optical fiber interferometer and the white light interferometric strips spatially
separated, it is called a SDM technique. As shown in FIG. 1, the input beam of the lxN fiber
splitter embedded in the measurement arm of the fiber interferometer is distributed into N paths,
and at the same time, different M optical reflective surfaces are set in each path that is
distributed, which is equivalent to NxM interferometers nested and multiplexed together.
Correspondingly, by embedding an optical path step accumulating-type optical delay line and a
continuously variable optical delay line in the reference arm of the optical fiber interferometer,
for the matching and scanning of the reference beam optical path, the optical path scanning can
be achieved directly using the continuously variable optical delay line in a small range, and the
optical path matching in a large range can be achieved using the optical path step accumulating
type optical delay line in conjunction with the continuously variable optical delay line. The
optical path experienced by the measurement beam through different optical bypasses and
different reflective surfaces (optical fiber interferometer) can be matched with the reference
beam's optical path in a one-to-one correspondence, so that the resulting white light interference
strips in the optical scan space are independent of each other, and do not interfere with each
other, based on the above ideas can be realized the nest-multiplexing of NxM optical fiber
interferometers.
[0024] The advantages and features of the invention are:
[0025] (1) The present invention is based on SDM technology, and the interferometric optical fiber interferometer is constructed by embedding a fiber splitter and an optical path step accumulating-type optical delay line, which can interrogate and measure a multi-fiber interferometer (sensor) without using complex time, frequency or wavelength multiplexing techniques but via space-continuous optical path scanning, which is in a simple structure and easy to achieve.
[0026] (2) The multiplexing optical fiber interferometer constructed by the present invention can make the number of multiplexed interferometers (sensors) reach nearly one hundred by selecting a broad spectrum light source of suitable power and a sufficient number of optical fiber splitters, and also realize the arraying and networking of optical fiber sensors, which greatly simplifies the complexity of the system, reduces the testing cost, ensures the real-time performance of the testing system, and improves the reliability of the measurement.
[0027] (3) The optical fiber materials and devices used in the present invention are standard optical fiber communication components, which are inexpensive, readily available, and conducive to promotion.
[0028] The patent of the present invention proposes a multiplexing method of a white light interferometer based on SDM technology, aiming at solving the disadvantages of low number of multiplexing, complicated structure or expensive cost of the interferometer to meet the requirements of practical measurement applications. The 2x2 fiber coupler has a spectral ratio of 3dB (1:1), its advantage is the enhanced contrast of interference signals. The advantage of using a 1xN optical fiber splitter (optical fiber switch or optical fiber coupler) in conjunction with an optical path step accumulating-type optical delay line is that the optical path of the interferometer can be extended, the nesting and multiplexing of N optical fiber interferometers can be realized, the number of sensors carried by the interferometer can be increased, and this leads to the arraying and networking of sensors.
[0029] FIG. 1 is a schematic diagram of the structure of the multiplexing optical fiber interferometer.
[0030] FIG. 2 is a schematic diagram of the structure of a parallel multiplexing optical fiber interferometer utilizing a 1x4 optical fiber switch.
[0031] FIG. 3 is a schematic diagram of the structure of a tandem multiplexing interferometer using a 2x8 optical fiber switch.
[0032] FIG. 4 is a schematic diagram of the construction of a multiplexing optical fiber interferometer using an optical fiber Fabry-Perot resonant cavity.
[0033] FIG. 5 is a schematic diagram of the structure of a multiplexing optical fiber interferometer constructed using an optical fiber circular resonant cavity.
[0034] The invention is described in more detail below in connection with the drawings:
[0035] Embodiment 1:
[0036] In conjunction with FIG. 1, this embodiment consists of a broad spectrum light source 1 and a photodetector 2. The broad spectrum light source 1 and the photodetector 2 are connected to two optical fiber inputs of an optical fiber 2x2 coupler 3, the two optical fiber outputs of the optical fiber 2x2 coupler 3 are connected to an optical fiber splitter 6 and an optical path step accumulating-type optical delay line 7 via single-mode fibers 4 and 5, the optical path step accumulating-type optical delay line 7 is connected to a continuously variable optical delay line 8, and the optical fiber splitter 6 is connected to a nest-multiplex opticalfiber interferometer array 9. In which, the optical fiber 2x2 coupler 3 is a 3dB fiber 2x2 coupler, the optical fiber splitter is a single-mode patchcord, and the optical path step accumulating-type optical delay line is a single-mode patchcord.
[0037] Embodiment 2: a parallel multiplexing optical fiber interferometer utilizing a 1x4 optical fiber switch.
[0038] In conjunction with FIG. 2, this embodiment consists of a broad spectrum light source 1, a photodetector 2, a 3dB optical fiber 2x2 coupler 3, a reference arm single-mode connection optical fiber 5, a continuously variable optical delay line 8, a 1x4 optical fiber switch 10, and an optical fiber end-reflectance mirror 11. The light source 1 and the photodetector 2 are connected to two optical fiber inputs of the 3dB single-mode optical fiber 2x2 coupler 3, the two optical fiber outputs of the optical fiber are connected to the 1x4 optical fiber switch 10 and the continuously variable optical delay line 8, respectively. The 1x4 optical fiber switch 10 is used to change the optical paths to realize the connection to different interferometers, meanwhile work in conjunction with the continuously variable optical delay line 8 to scan optical paths to obtain different white light interference strips and realize the nest-multiplexing of optical fiber interferometers. This structured optical fiber interferometers have a multiplex number of 4.
[0039] Embodiment 3: a tandem multiplexing interferometer using a 2x8 optical fiber switch.
[0040] In conjunction with FIG. 3, the broad spectrum light source 1, the photodetector 2, the
3dB optical fiber 2x2 coupler 3, and the continuously variable optical delay line 8 in this
embodiment is the same as FIG. 2. The difference is the addition of an optical path step
accumulating-type optical delay line consisting of a 2x8 optical fiber switch 13 and single-mode
fibers 5 of different lengths connected to the reference arm, and reflective surfaces 12. In
addition, the structure of the nested optical fiber interferometer has been changed from a parallel
connection type to a serial connection type that connects the head and tail of the optical fiber
interferometer. When the optical fiber interferometer is in operation, the measurement beam
enters an array of four optical fiber interferometers (optical fiber sensors) connected serially,
creating a series of reflected measurement signals with different optical paths. The reference
beam is connected to the optical fiber switch 13 with different matching lengths of optical fibers
and the continuously variable optical delay line 8, through the switching of the former and with
the optical path scanning of the latter, the optical paths of the reference beam and the
measurement beam are matched to obtain the white light interference strips and realize the nest
multiplexing of optical fiber interferometers. Since the 2x8 optical fiber switch 13 can connect
only 4 optical fiber patchcords of different lengths, the number of multiplexing optical fiber
interferometers for this configuration is 4.
[0041] Embodiment 4: a multiplexing optical fiber interferometer using an optical fiber Fabry
Perot resonant cavity.
[0042] In conjunction with FIG. 4, compared to FIG. 2, the difference is that the 2x8 optical fiber switch 13 is replaced by an optical fiber Fabry-Perot resonant cavity 14. The optical fiber Fabry
Perot resonant cavity consists of a ceramic insert 1401, a ceramic sleeve 1402, an optically
transmitted reflective coating 1403 coated on the end face of the fiber, and a single-mode fiber
1404 that forms the Fabry-Perot resonant cavity. It also utilizes the multiple reflections of the
light beam in the resonant cavity to achieve the step accumulation of the optical paths, and the
rough matching of the optical path of the reference beam and the measurement beam. An array
interferometer with N serial arrays combined with M parallel surfaces connected by an optical
fiber splitter 6 greatly increases the number of multiplexing of the opticalfiber interferometer.
For example, when N=8, M=16, the multiplexing number of this structured interferometer can be
up to 128. Replacing the optical fiber switch with an optical fiber Fabry-Perot resonant cavity
also reduces the cost of the system. Also the pairing of discrete fibers in the optical fiber switch
to match the optical path into one also improves the interference immunity characteristics of the
optical path system.
[0043] Embodiment 5: a multiplexing optical fiber interferometer constructed using an optical
fiber circular resonant cavity.
[0044] In conjunction with FIG. 5, the optical fiber interferometer in this embodiment, in
comparison to FIG. 4, the difference is to use the optical fiber circulator resonant cavity 15 to
replace the optical fiber Fabry-Perot resonant cavity 14 which has the same functions. Similarly,
if N=8, M=16, the multiplexing number of this structured interferometer can be up to 128. The
advantage of this new structure is that the optical fiber circular cavity can be fabricated using the
proven fusion taper process, which eliminates the need for the Fabry-Perot resonant cavity end
face coating, making it easier and less expensive to implement.
Claims (7)
1. The construction method of a multiplexing optical fiber interferometer, it is based on the
principle of space division multiplexing (SDM), the broad spectrum light emitted from the light
source is split by the fiber splitter, then connected to the measurement optical path of the nest
multiplex fiber interferometer, its characteristics are: using the accumulated optical paths
resulted from the reference light beam transmitting back and forth many times in the optical path
step accumulating-type optical delay line, and match with the optical path received by the
measurement light beam in the nest-multiplex interferometer measuring optical path, to achieve
white light interference strips. Then, the measurement of deformation, strain, temperature,
pressure and other physical quantities can be completed.
2. A multiplexing optical fiber interferometer, it comprises a broad spectrum light source (1)
and a photodetector (2), characterized as follows: the broad spectrum light source (1) and the
photodetector (2) are connected to two optical fiber inputs of an optical fiber 2x2 coupler (3), the
two optical fiber outputs of the optical fiber 2x2 coupler (3) are connected to an optical fiber
splitter (6) and an optical path step accumulating-type optical delay line (7) via single-mode
fibers (4) and (5), the optical path step accumulating-type optical delay line (7) is connected to a
continuously variable optical delay line (8), and the optical fiber splitter (6) is connected to a
nest-multiplex optical fiber interferometer array (9).
3. As claimed in claim 1, a multiplex optical fiber interferometer, its characteristics also
include: 1) The fiber 2x2 coupler (3) is a 3dB optical fiber 2x2 coupler. 2) The fiber splitter (6) is
a single mode optical fiber patchcord. 3) The optical fiber splitter (6) is a 1xN star-type optical
fiber coupler.
4) The optical fiber splitter (6) is a 1xN optical fiber switch.
5) The optical path
step accumulating-type optical delay line (7) is a single mode optical fiber patchcord.
6) The
optical path step accumulating-type optical delay line (7) is a multi-pathfiber switch connected with different lengths of single-mode fibers.
7) Optical path step accumulating-type optical delay line (7) is an optical fiber Fabry-Perot resonant cavity or an optical fiber circular resonant cavity.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114383527A (en) * | 2022-03-23 | 2022-04-22 | 武汉奇测科技有限公司 | Multi-channel grating demodulation device and method for frequency multiplexing and demultiplexing |
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2020
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114383527A (en) * | 2022-03-23 | 2022-04-22 | 武汉奇测科技有限公司 | Multi-channel grating demodulation device and method for frequency multiplexing and demultiplexing |
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