CN205642638U - Simple and easy low -cost real -time measuring device of wavelength - Google Patents

Abstract

The utility model discloses a simple and easy low -cost real -time measuring device of wavelength. The low -voltage line phase sequence signboard is advantageous in that, when being bare behind 1 minute 4 fiber coupler, the luminous power will be four by the average mark, wherein a branch of light links to each other then inserts a photoelectric detector with linear filter earlier, a branch of light is direct in addition is connected with the 2nd photoelectric detector, two bundle remaining light link to each other with the optic fibre circulator earlier respectively simultaneously, then connect two F separately the P etalon, link to each other with the 3rd photoelectric detector and fourth photoelectric detector respectively after that, two light of two circulator branch roads 3 outgoing link respectively to the 5th photoelectric detector and the 6th photoelectric detector in from being direct, then six light whole data collection card that insert behind photoelectric conversion with the photoelectric detector outgoing, last data collection card is connected to the computer. The utility model discloses compact structure is simple, and is with low costs, and measuring range is big, but the precision metrology field is applied to to the real -time measurement.

Description

A kind of wavelength real-time measurement apparatus of Simple low-cost

Technical field

This utility model belongs to laser frequency spectrum characterisitic parameter fields of measurement, for measuring the wavelength value of unknown laser.

Background technology

Laser as a kind of light source owing to its monochromaticity is good, the feature such as high directivity, dispersion be little modern science and technology with Engineering practice is widely used.Optical maser wavelength is the reference value of physical detection, be widely used in length, speed, The measurement of angle, flatness, linearity and perpendicularity etc., is that delicate metering, precision optical machinery and microelectronics industry are important Measure parameter.Accurately Laser Measurement wavelength, the basic research at optics has great importance with application.Present ripple Length measuring apparatus device is mainly spectrogrph and band meter, but light splitting type spectrogrph is limited to its measuring principle and can only realize laser center The rough measure (about tens pm) of wavelength, and price comparison is expensive；Band meter is because of the advantage of its high-acruracy survey, and by extensively It is applied in the measurement of optical maser wavelength.The band meter of modern Commercial is classified according to measuring principle, mainly has Fizeau interference type wavelength Meter, Fabry-Perot interference type band meter and Michelson interference type band meter, its basic functional principle is all based on the dry of light Relate to, but the above two are required for area array CCD detection interference fringe and the image procossing of complexity；([1] Wu Rui female .F-P etalon System for laser wavelength measurement. Chinese laser, 1986,14 (5): 287-291. [2] Song Jianming, degree of being virtue. utilize Fizeau interference to survey Amount optical maser wavelength. Quantum Electronics journal, 2001,18 (3): 224-227.) both (Fabry-Perot interference type and Michaels afterwards Inferior interference-type) it is required for built-in reference laser instrument, the interference bar produced by reference laser known to wavelength value and testing laser Stricture of vagina contrasts, thus obtains the wavelength value of testing laser.([3] Lu Hong. utilize F-P Real-time measurement of laser wavelength Research. laser technology, 1996,20 (3): 143-146. [4] Wang Liqiang, Zuo Aibin, Peng Yuexiang. dividing of optical wavelength measurement instrument Class, principle and progress. science and technology Leader, 2005,23 (6): 31-33) these factors all make present band meter relatively costly, And limited by principle and cannot be reduced cost on a large scale.It addition, Michelson interference type band meter (such as HP 81620c) is due to interior Put mechanical scanning parts, affected by vibration greatly, it is impossible to the place complex at environment is run, and is difficult to burst pulse light Wavelength measurement.

Utility model content

The utility model proposes a kind of without reference to laser instrument, utilize double F-P (Fabry-P é rot) etalon with linear The wavelength real-time measurement apparatus of the Simple low-cost that wave filter combines.I.e. incident illumination is after beam splitting, linear by one respectively Wave filter and two F-P etalons, the optical power value passed through by measurement realizes the accurate measurement to optical maser wavelength.This device energy Enough the most on a large scale, high-precision Measurement of Laser Wavelength in Real-time, there is compact conformation simple, low cost, it is easy to the features such as operation.

It is achieved through the following technical solutions:

A kind of wavelength real-time measurement apparatus of Simple low-cost, it is characterised in that: by 1 point of 4 light bonder (1), linear Wave filter (2), optical fiber circulator (3), a F-P etalon (4), the 2nd F-P etalon (5), temperature control equipment (6), One photodetector (7), the second photodetector (8), the 3rd photodetector (9), the 4th photodetector (10), the 5th light Electric explorer (11), the 6th photodetector (12), data collecting card (13) and computer (14) composition, the position of each part mentioned above Relation is as follows:

Testing laser through 1 point of 4 fiber coupler (1) decile four bundle light respectively by optical fiber 1., optical fiber 2., optical fiber 3., optical fiber be 4. connected with device below, optical fiber 1. in light through linear filter (2) by the first photodetector (7) detect, Optical fiber 2. in light directly by the second photodetector (8) detect；Optical fiber the most first connects an optical fiber circulator (3), circulator Branch 2 connect a F-P etalon (4), the transmission light through a F-P etalon (4) is visited by the 3rd photodetector (9) Surveying, the reflection light of another branch 3 is detected by the 4th photodetector (10)；Optical fiber the most first connects an optical fiber circulator (3), the branch 2 of circulator connects the 2nd F-P etalon (5), and then its transmission light is detected by the 5th photodetector (11), another The reflection light of branch 3 is detected by the 6th photodetector (12)；The 6 of first photodetector (7)-the six photodetector (12) The individual signal of telecommunication by data collecting card (13) gather, finally by computer (14) analytical calculation thus obtain testing laser wavelength, its In, a F-P etalon (4) and the 2nd F-P etalon (5) are individually positioned in temperature control equipment (6) with the extraneous temperature of isolation The impact of degree change.(structured flowchart is as shown in Figure 1)

Described linear filter, within the specific limits, after the laser light incident of different wave length, its luminous power passed through can not With, determine roughly wavelength from there through the optical power value detected.Limited based on principle, the response to wavelength of the F-P etalon It is sinusoidal cycles change, and the main purpose of linear filter just determines that lambda1-wavelength value is corresponding to F-P etalon The sinusoidal cycle accurate of wavelength response, so that it is determined that the accurate monotony interval in a periodic regime, so linearly The wavelength resolution of wave filter should be less than the 1/4 of F-P etalon FSR (Free Spectral Range).

The each self-corresponding light intensity-wavelength curve of two described F-P etalons is sinusoidal pattern, and the phase contrast of two curves Be 90 degree, there is the wavelength response characteristic of complementation, therefore two F-P etalons can be used to compensate mutually at response curve crest and Measurement near trough, thus improve certainty of measurement；Temperature control equipment uses two pieces of copper billets the most closely to paste with F-P etalon Closing, semiconductor chilling plate (15) is attached to copper billet bottom surface, critesistor (16) is placed in for Real-time Collection temperature value inside copper billet, External temperature control circuit (17) constitutes negative feedback Guan Bi control system, uses pid algorithm to carry out accurate temperature control, controls essence Degree is 0.001 degree, and the wavelength control precision of its correspondence is 0.1nm.(attemperating unit is as shown in Figure 2)

The utility model has the advantage of: 1, all optical fibre structure, flexible layout, it is not necessary to Space Collimation, greatly reduce The impact of the uncontrollable factors such as the light suffered environment in transmitting procedure, has widened the application of this wavelength measuring apparatus and has made Use condition.2, principle aspect, measurement system described in the utility model only need to separately detect the light merit through double F-P chambers and wave filter Rate, it is possible to measure the wavelength value of incident laser, it is not necessary to image procossing, the data in later stage process simple；3, this utility model Described measurement system is without using reference laser diode and area array CCD, so that the cost of system is lower.

Accompanying drawing explanation

Fig. 1 is structured flowchart of the present utility model；

Fig. 2 is temperature control equipment figure of the present utility model；

Fig. 3 is the I of F-P etalon^(t)/I^(r)～λ oscillogram；

Fig. 4 is the compensation experiment result oscillogram of F-P etalon；

Fig. 5 is the flow chart of wavelength measurement.

Detailed description of the invention

Operation principle of the present utility model:

F-P cavity etalon is made up of two pieces of flat glass plates being placed in parallel, and the inner surface of two plates is plated with high reflectance Silverskin or aluminum film, its structure can regard one piece of parallel plane glass plate as, and due to the characteristic of F-P cavity two ends highly reflecting films, light is in chamber Reflection the most back and forth and refraction, if optical signal is not absorbed by the left and right both ends of the surface of parallel plane glass plate, when to be measured When laser θ at an angle incides F-P cavity etalon, through a series of deduction, intensity of reflected light and transmission can be drawn The ratio of light intensity is

$I^{\left(r\right)}/I^{\left(t\right)}=\frac{4{\mathrm{Rsin}}^2\frac{\mathrm{\δ}}{2}}{{(1-R)}^2}---(1-1)$

δ is phase place, and R is the reflectance of high reflection film in F-P etalon.

By phase place and the relation of chamber length

δ=K Δ=K 2nl cos θ (1-2)

In formula: Δ is the optical path difference of adjacent beams；K is the transmission of light in free space, K=2 π/λ；N is intracavity Refractive index；L is that chamber is long；θ is the light angle at intracavity reflecting.

Can obtain in conjunction with formula (1-1) and (1-2):

$I^{\left(r\right)}/I^{\left(t\right)}=\frac{4R}{{(1-R)}^2}{\sin }^2\left(\frac{2n\mathrm{\π}lcos\mathrm{\θ}}{\mathrm{\λ}}\right)---(1-3)$

If the central wavelength lambda of incident laser₀It is that 100GHz is (between wavelength for 1550nm, the FSR of corresponding F-P etalon It is divided into 0.8nm), by Free Spectral Range

$\mathrm{\Δ}\mathrm{\λ}={\mathrm{\λ}}_0^2/2nl---(1-4)$

Understand 2nl=3003000nm, substitute into equation (1-3), take the reflectance of high reflection film when being 0.8, swash when to be measured When light near normal is incident to F-P etalon, θ=0, cos θ=1.Corresponding I after normalization^(t)/I^(r)～λ waveform such as Fig. 3 institute Show.

From the periodicity of shown oscillogram, when we detect an optical power value, at wavelength response curve In one cycle in addition to wave crest point and trough point, all to there being two wavelength value (a, b 2 point as in Fig. 3).Here we The linear filter used is 0.1nm to the resolution of signal light wavelength, and the FSR of F-P etalon be 100GHz (about 0.8nm), the resolution of wave filter is less than 1/4 cycle wavelength interval of wavelength response curve, so we can be according to recording Wavelength value corresponding to linear filter absorbance, certain further determining that wavelength response curvilinear abscissa place is accurately single Adjust interval (i.e. Fig. 3 determines from a, b more corresponding wavelength value) at 2, finally try to achieve now luminous power corresponding Exact wavelengths λ value.

But when 0 be substantially equal to for the wavelength response slope of curve (near crest in oscillogram and trough), by In factors such as photodetector thermal noise, amplifying circuit noises, reliability and the verity of data can be largely effected on.

From equation (1-3), we can be by changing the value of relevant unknown number, so that I^(t)/I^(r)～λ curve On the basis of original, produce the phase shift of about 90 degree, dephased wavelength response curve thus can be utilized to compensate artwork shape Error near crest and trough.Herein, we allow the phase shift produced be about 90 degree of (1/4 of corresponding wavelength response curve Cycle) so that the crest of former wavelength response curve (I) and trough correspond to the line of dephased wavelength response curve (II) The region that property degree is high, as shown in Figure 4, is positioned at crest when we detect the optical power value (at c point) of former wavelength response curve (I) Or time near trough, at this moment we take the optical power value of dephased wavelength response curve (II) correspondence that the same time is detected (at d point), corresponding λ value (at e point), the most just obtain the exact wavelengths value of now testing laser.

The beneficial effects of the utility model are:

This device uses the wavelength of linear filter elder generation rough measure testing laser, determines that it is corresponding at F-P etalon The accurate a certain periodic regime of light intensity-wavelength curve；Each self-corresponding by a F-P etalon and the 2nd F-P etalon again The combination of light intensity-wavelength curve, it is possible to obtain wavelength value accurately.This method not only avoid image processing step, greatly Simplifying greatly the data in later stage to process, and make whole apparatus structure compact simply, small volume is easy to carry about with one；First photoelectricity Detector and the second photodetector are one group, and the 3rd photodetector and the 4th photodetector are one group, the 5th smooth electrical resistivity survey Surveying device and the 6th photodetector is one group, such measurement of comparison can be got rid of the measurement caused because of incident optical power change and miss Difference；Temperature control equipment closely connects slightly with a F-P etalon, the 2nd F-P etalon respectively, finally realizes high-precision temperature control System, is used for getting rid of ambient temperature and changes its harmful effect.Make this apparatus structure compact simply based on above character, cost Low, measure scope big, optical wavelength can be measured in real time.

To sum up, the important flow process of the part of the present invention is as follows:

The week determined to certain by the wavelength response curve being reduced F-P etalon by the optical power value of linear filter Interim monotony interval；Then, if the optical power value recorded is in the high region of the wave function linearity, just read the 3rd photodetection Device (5) and the optical power value of the 4th photodetector (6)；If the optical power value recorded is near crest or trough time, this Time read the 3rd photodetector (7) and the optical power value of the 6th photodetector (8)；Finally combine the optical power value recorded to ask Go out corresponding wavelength value.(flow chart is as shown in Figure 5)

The wavelength measurement step of the present invention is:

Step 1) according to Fig. 1, connect light path: testing laser is through four bundle light difference of 1 point of 4 fiber coupler (1) decile By optical fiber 1., optical fiber 2., optical fiber 3., optical fiber be 4. connected with device below, optical fiber 1. in light through linear filter (2) quilt First photodetector (7) detect, optical fiber 2. in light directly by the second photodetector (8) detect；Optical fiber the most first connects one Individual optical fiber circulator (3), the branch 2 of circulator connects a F-P etalon (4), through the transmission light of a F-P etalon (4) By the 3rd photodetector (9) detection, the reflection light of another branch 3 is detected by the 4th photodetector (10)；Optical fiber is the most same The most first connecting an optical fiber circulator (3), the branch 2 of circulator connects the 2nd F-P etalon (5), and then its transmission light is by the 5th Photodetector (11) detects, and the reflection light of another branch 3 is detected by the 6th photodetector (12)；First photodetector 6 signals of telecommunication of (7)-the six photodetectors (12) are gathered by data collecting card (13), finally by computer (14) analysis meter Calculate thus obtain testing laser wavelength.

Step 2) according to Fig. 2, temperature controls: temperature control equipment uses two pieces of copper billets the most closely to paste with F-P etalon Closing, semiconductor chilling plate (15) is attached to copper billet bottom surface, critesistor (16) is placed in for Real-time Collection temperature value inside copper billet, External temperature control circuit (17) constitutes negative feedback Guan Bi control system, uses pid algorithm to carry out accurate temperature control, controls essence Degree is 0.001 degree, and the wavelength control precision of its correspondence is 0.1nm.

Step 3) data acquisition and procession: with reference to Fig. 1, the first photodetector (7) is visited to the 6th photodetector (12) Survey six passage Output optical power；Then being connected to by all channel signals in data collecting card (8), data collecting card (13) leads to Cross USB connect computer (14), finally by computer (14) analytical calculation thus obtain testing laser wavelength.

Claims (4)

1. the wavelength real-time measurement apparatus of a Simple low-cost, it is characterised in that: by 1 point of 4 light bonder (1), linearly filter Ripple device (2), optical fiber circulator (3), a F-P etalon (4), the 2nd F-P etalon (5), temperature control equipment (6), first Photodetector (7), the second photodetector (8), the 3rd photodetector (9), the 4th photodetector (10), the 5th photoelectricity Detector (11), the 6th photodetector (12), data collecting card (13) and computer (14) composition, the position of each part mentioned above is closed It is as follows:

Testing laser through 1 point of 4 fiber coupler (1) decile four bundle light respectively by optical fiber 1., optical fiber 2., optical fiber 3., light 4. fibre is connected with device below, optical fiber 1. in light through linear filter (2) by the first photodetector (7) detect, optical fiber 2. the light in is directly detected by the second photodetector (8)；Optical fiber the most first connects an optical fiber circulator (3), dividing of circulator Road 2 connects a F-P etalon (4), and the transmission light through a F-P etalon (4) is detected by the 3rd photodetector (9), separately The reflection light of one branch 3 is detected by the 4th photodetector (10)；Optical fiber the most first connects an optical fiber circulator (3), The branch 2 of circulator connects the 2nd F-P etalon (5), and then its transmission light is detected by the 5th photodetector (11), another branch The reflection light of 3 is detected by the 6th photodetector (12)；6 electricity of the first photodetector (7)-the six photodetector (12) Signal is gathered by data collecting card (13), finally by computer (14) analytical calculation thus obtain testing laser wavelength, wherein, the One F-P etalon (4) and the 2nd F-P etalon (5) are individually positioned in temperature control equipment (6) with isolation ambient temperature change Impact.

The wavelength real-time measurement apparatus of a kind of Simple low-cost the most according to claim 1, it is characterised in that: by measuring Laser estimates roughly light wave long value by the absorbance of linear filter (2)；Owing to a F-P etalon (4) and the 2nd F-P mark The absorbance of quasi-tool (5) is sinusoidal cycles change to the response of wavelength, and linear filter is mainly used to determine lambda1-wavelength It is worth wavelength response which cycle, the therefore line sinusoidal corresponding to a F-P etalon (4) and the 2nd F-P etalon (5) Property wave filter (2) measurement error of optical maser wavelength be should be less than a F-P etalon (4) and the 2nd F-P etalon (5) wavelength ring Answer the 1/4 of sinusoidal periodic.

The wavelength real-time measurement apparatus of a kind of Simple low-cost the most according to claim 1, it is characterised in that: a F-P The phase contrast of etalon (4) and the 2nd F-P etalon (5) is 90 degree, such F-P etalon (4) or the 2nd F-P etalon (5) crest of wavelength response curve and trough both correspond to the 2nd F-P etalon (4) or a F-P etalon (5) is linear District, can solve the measurement that wavelength response sine curve causes at crest and trough vicinity by the way of this complementary measurement The problem that error is big.

The wavelength real-time measurement apparatus of a kind of Simple low-cost the most according to claim 1, it is characterised in that: temperature control Device processed (6) uses two pieces of copper billets to fit tightly up and down with a F-P etalon (4) and the 2nd F-P etalon (5) simultaneously, will Semiconductor chilling plate is attached to copper billet bottom surface, and critesistor is placed in for Real-time Collection temperature value inside copper billet, and external temperature controls Circuit constitutes negative feedback closed loop control system.