CN102654422A - Optical frequency domain vernier method spectrograph - Google Patents
Optical frequency domain vernier method spectrograph Download PDFInfo
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- CN102654422A CN102654422A CN2012100655593A CN201210065559A CN102654422A CN 102654422 A CN102654422 A CN 102654422A CN 2012100655593 A CN2012100655593 A CN 2012100655593A CN 201210065559 A CN201210065559 A CN 201210065559A CN 102654422 A CN102654422 A CN 102654422A
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Abstract
The invention discloses an optical frequency domain vernier method spectrograph, comprising an incident collimating lens, a tunable F-P interferometer, an F-P etalon, a first optical fiber circulator, a first optical fiber circulator, a second optical fiber circulator, a first photoelectric detection device, a power measurement module, a second photoelectric detection device and a wavelength demodulation module, wherein the incident collimating lens is used for coupling incident light to be tested into an optical fiber; the tunable F-P interferometer is used for selecting partial optical wave from the incident collimating lens to pass through the cavity by tuning the cavity length of the tunable F-P interferometer; the F-P etalon is used for extracting the optical valve with specific frequency from the tunable F-P interferometer; the first optical fiber circulator is used for isolating reflected light and located between the tunable F-P interferometer and the etalon; and the optical wave is transmitted between the input port of the second optical fiber circulator and the F-P etalon. According to the invention, the application of Michelson interferometer having great volume and a grating-image sensor structure is avoided, and optical frequency selection is realized; and the cavity length of a resonant cavity can be tuned at a tiny amplitude, thereby avoiding the technical problem caused by movable parts..
Description
Technical field
The present invention relates to a kind of optical frequency territory vernier method spectrometer, belong to the spectrographic detection field, can be applied to the fields such as mensuration, optical communication and Fibre Optical Sensor of the absorption spectrum of material.
Background technology
The prior art of measuring spectrum mainly contains two types at present.One type is that light wave with different wave length is distributed on the different direction in spaces, and wherein common beam splitter is prism and grating.Another kind of is that light wave with different wave length separates in time, and wherein Fourier transform spectrometer, commonly can utilize Michelson interferometer or Mach-Zehnder interferometer to realize.
One of formerly technological; Utilize grating that the light wave of different wave length is distributed to different direction in spaces; Utilize linear detector array or linear image sensor (like CCD or cmos image sensor) to survey the power of different wave length light wave, obtain spectrum to be measured thus.The advantage of this method is: response speed is fast, and wavelength resolution also can be very high.Shortcoming mainly is to need bigger distance between detector and the grating, thereby causes the machining difficulty, the equipment heavy, and cost an arm and a leg.
Formerly two of technology, light wave is imported a Michelson-or Mach-Zehnder interferometer, the light wave of output is the coherent light of the light wave that transmits in two arms, its power is the function of wavelength and phase differential.Through regulating the length of a light arm, change phase differential, can obtain luminous power with the long variation in chamber.And the relation of spectrum and this signal just in time is the cosine Fourier transform, therefore, through finding the solution inverse Fourier transform, can obtain spectrum to be measured.The advantage of this method is that spectrographic detection scope and wavelength resolution are all very high.Shortcoming is: expend time in very much, can not measure and change spectrum faster; Have moving component, also very high to the requirement of machining; Equipment is also huge and expensive.Therefore how to overcome above-mentioned technical matters in the prior art, become the direction that those of ordinary skills make great efforts.
Summary of the invention
The object of the invention provides a kind of optical frequency territory vernier method spectrometer, has avoided using bigger Michelson interferometer and the grating-image sensor architecture of volume, and has realized the light frequency selection; And can be on very little amplitude the chamber of tuned resonating cavity long, avoided adopting the technical matters that movable part produced.
For achieving the above object, the technical scheme that the present invention adopts is: a kind of optical frequency territory vernier method spectrometer comprises:
The incident collimation lens is used for incident light to be measured is coupled into optical fiber;
Tunable F-P interferometer, it is selecting part to pass through from said incident collimation lens light wave through tuning its chamber length;
The F-P etalon is used for extracting the light wave from said tunable F-P interferometer CF;
Be used to isolate catoptrical first fiber optical circulator, between tunable F-P interferometer and F-P etalon, be used to receive light wave from tunable F-P interferometer;
Second fiber optical circulator transmits light wave between this second fiber optical circulator input port and the said F-P etalon;
First Electro-Optical Sensor Set is connected to said second fiber optical circulator, first output port, is used for light wave is converted into electric signal;
Power measurement module is calculated luminous power according to the electric signal from first Electro-Optical Sensor Set, and sampling also stores the luminous power data;
Second Electro-Optical Sensor Set is connected to said second fiber optical circulator, second output port, is used for light wave is converted into electric signal;
The Wavelength demodulation module, according to the luminous power of calculating from the electric signal of second Electro-Optical Sensor Set after light wave that stabilized light sent passes total system, the luminous power data are also preserved in sampling, and demodulation obtains wavelength data from the luminous power data.
Further improved technical scheme is following in the technique scheme:
As preferably, two end mirrors have different reflectivity in different wavelengths in the said tunable F-P interferometer.
As preferably, also comprise: stabilized light, receive light wave from the 3rd port transmission in said first fiber optical circulator, the frequency stabilization benchmark light wave that this stabilized light sends is coupled into optical fiber through coupling mechanism with from the light wave of incident collimation lens;
The light wave that first fiber coupler, stabilized light send is superimposed through coupling mechanism and light wave to be measured, and together passes through interferometer;
Fiber Bragg Grating FBG between said second fiber optical circulator and first Electro-Optical Sensor Set, will reflect from the light wave that stabilized light sends, and the frequency range of its stopband and light wave to be measured staggers.
As preferably, also comprise: stabilized light is used to provide a frequency stabilization benchmark light wave;
The 3rd fiber optical circulator, its 1st port receive said frequency stabilization benchmark light wave, the 3rd fiber optical circulator the 2nd port and said F-P etalon transmission light wave, the 3rd fiber optical circulator the 3rd port and said second fiber optical circulator the 1st port transmission light wave;
Fiber Bragg Grating FBG between said second fiber optical circulator and Electro-Optical Sensor Set, will reflect from the light wave that stabilized light sends, and the frequency range of its stopband and light wave to be measured staggers.
As preferably, also comprise: stabilized light is used to provide a frequency stabilization benchmark light wave;
Second fiber coupler, being used for the wavelength-division of frequency stabilization reference light is two-way;
The light wave that first fiber coupler, stabilized light send is superimposed through first fiber coupler and light wave to be measured, and together passes through interferometer;
The 3rd fiber optical circulator; Its 1st port receives the frequency stabilization benchmark light wave from second fiber coupler; The 3rd fiber optical circulator the 2nd port and said F-P etalon transmission light wave, the 3rd fiber optical circulator the 3rd port and said second fiber optical circulator the 1st port transmission light wave;
First Electro-Optical Sensor Set is connected to said second fiber optical circulator, first output port, is used for light wave is converted into electric signal;
Second Electro-Optical Sensor Set is connected to said second fiber optical circulator, second output port, is used for light wave is converted into electric signal;
Fiber Bragg Grating FBG between said second fiber optical circulator and Electro-Optical Sensor Set, will reflect from the light wave that stabilized light sends, and the frequency range of its stopband and light wave to be measured staggers.
As preferably, the light frequency of said stabilized light and the scope of spectrum to be measured stagger.
Because the technique scheme utilization, the present invention compared with prior art has advantage and effect:
1, the present invention utilizes the very little resonator cavity of two volumes to realize the function that light frequency is selected, avoided using the bigger Michelson interferometer of volume, or the free space propagation distance of growing in grating-image sensor architecture.
2, the present invention only needs a photodetector, has avoided using the imageing sensor of expensive instrument level.
3, the present invention only need be on very little amplitude in the process of scan light frequency the chamber of tuned resonating cavity long.Therefore can adopt means such as electrooptical modulation, avoid adopting the problem that movable part caused.
4, spectral resolution of the present invention can reach high resolving accuracy at an easy rate by the Free Spectral Range decision of etalon.
Description of drawings
Fig. 1 structure of the present invention;
The power transmission spectrum of Fig. 2 resonator cavity;
The power transmission spectrum of Fig. 3 etalon 7 and interferometer 3;
Fig. 4 realizes frequency sweeping through tuning interferometer 3;
Fig. 5 interferometer 3 is at the end face reflection rate and the power transmission spectrum of different-waveband;
The amplitude modulation(PAM) that Fig. 6 etalon 7 and 3 pairs of wavelength-modulated light waves of interferometer apply;
The voltage signal of Fig. 7 tuned resonance cavity length.
In the above accompanying drawing: 1, incident collimation lens; 2, first fiber coupler; 3, tunable F-P interferometer; 4, first fiber optical circulator; 5, stabilized light; 6, second fiber coupler; 7, F-P etalon; 8, the 3rd fiber optical circulator; 9, second fiber optical circulator; 10, Fiber Bragg Grating FBG; 11, first Electro-Optical Sensor Set; 12, second Electro-Optical Sensor Set; 13, power measurement module; 14, Wavelength demodulation module.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is further described:
Embodiment: a kind of optical frequency territory vernier method spectrometer,, shown in accompanying drawing 1, successively by incident collimation lens 1, the first fiber coupler 2; Tunable F-P interferometer 3, fiber optical circulator 4, stabilized light 5, the second fiber couplers 6; F-P etalon 7, fiber optical circulator 8, fiber optical circulator 9, Fiber Bragg Grating FBG (FBG) 10; First Electro-Optical Sensor Set 11, Electro-Optical Sensor Set 12, power measurement module 13, Wavelength demodulation module 14 constitutes.Its structure is as shown in Figure 1.The function of each composition characteristic and concrete working method are seen the narration of technical scheme part.
According to the knowledge of multiple-beam interference, the power transmission spectrum of resonator cavity presents pectination, and is as shown in Figure 2.Wherein Free Spectral Range (chamber longitudinal mode spacing) is inversely proportional to the interior light path (it is long to abbreviate the chamber as) of resonator cavity.The width of chamber longitudinal mode, just the width of transmitted spectrum is determined by fineness.Fineness is high more, and the shape of longitudinal mode is sharp-pointed more, and the longitudinal mode width D is narrow more.
Have the resonator cavity of two serial connections among the present invention, i.e. long variable F-P interferometer 3 in chamber and the long fixing F-P interferometer 7 in chamber.Both Free Spectral Ranges have a small difference, and are as shown in Figure 3, and Fig. 3 (a) is the transmission spectrum of F-P etalon, and Fig. 3 (b) is the transmission spectrum of tunable F-P interferometer, and both transmitted spectrums are at light frequency v
iThe place overlaps, and does not overlap at other any wavelength, and therefore, light wave to be measured passes after two resonator cavitys, and only remaining frequency is v
iMonochromatic optical wave.
According to the relevant knowledge of resonator cavity, its longitudinal mode frequency does
Wherein C is the light velocity, and L is a light path in the chamber, and n is a positive integer, is the sequence number of longitudinal mode.
Can obtain the Free Spectral Range of resonator cavity from formula (1), just the difference on the frequency of adjacent longitudinal mode does
Can find out that from formula (1) and formula (2) when changing the long L in chamber, the light frequency v at Free Spectral Range and n longitudinal mode place can change.But, long like the change amount Δ L that fruit caving is long much smaller than the chamber, promptly have relationship delta L＜＜L, can find out that from formula (2) some subtle change on the denominator can be to Free Spectral Range Δ v generation remarkable influence, we can think that Δ v is constant.On the other hand, at the optical frequency wave band, the ordinal number n of chamber longitudinal mode is very big.Therefore, some subtle change of Free Spectral Range (longitudinal mode spacing) all can add up, and make the light frequency at n longitudinal mode place produce significant the variation.In sum, the effect of the fine setting long L in chamber just is equivalent to the transmitted spectrum of translation resonator cavity, and is as shown in Figure 4.For the ease of difference, the position of the transmitted spectrum of interferometer 3 some have been moved down slightly among the figure.
Shown in accompanying drawing 4, wherein: V1: sampled light frequency 1, V2: sampled light frequency 2; V3: sampled light frequency 3, V4: sampled light frequency 4, V5: the spectrum of tunable F-P interferometer; The spectrum of V6:F-P etalon, d1: the skew of longitudinal mode, d2: the skew of sampled light frequency; Among Fig. 4 (a), when n longitudinal mode of m longitudinal mode of etalon 7 spectrum and interferometer 3 spectrum coincided, sampled light frequency 1 can be passed through; Among Fig. 4 (b), m+1 longitudinal mode and n+1 longitudinal mode coincide, and sampled light frequency 2 can be passed through; Among Fig. 4 (c), m+2 longitudinal mode and n+2 longitudinal mode coincide, and sampled light frequency 3 can be passed through; Among Fig. 4 (d), m+3 longitudinal mode and n+3 longitudinal mode coincide, and sampled light frequency 4 can be passed through.
We can find out from Fig. 4, the frequency of n the longitudinal mode very little value that only only drifted about, and the sampled light frequency of system has just been crossed over very big scope.These characteristics have determined very little of the long tuning value in chamber of wanting required for the present invention, thereby can adopt technology such as electrooptical modulation, have avoided the use movable part.
Technical scheme is as shown in Figure 1.
Incident light to be measured is coupled into optical fiber by collimation lens 1; Through coupling mechanism 2, get into interferometer 3; Interferometer 3 is optical filters of a pectination, and its transmitted spectrum is as shown in Figure 2.In the incident light wave to be measured, the light wave that has only the longitudinal mode of those frequencies and interferometer 3 to coincide can pass through.
The light wave of interferometer 3 outputs gets into circulator 4.So-called circulator is a kind of passive device of using always at optical communication and sensory field, and its function is: the light wave of 1 port incident is exported from 2 ports, and the light wave of 2 port incidents is exported from 3 ports, and the light wave of 3 port incidents is no-output then.(subordinate)
Light wave gets into 1 port of circulator 4, from the output of 2 ports, gets into etalon 7.The purpose of between interferometer 3 and etalon 7, inserting circulator 4 is in order to isolate reflected light.
Etalon 7 also is the optical filter of a pectination, its transmitted spectrum such as Fig. 2, shown in Figure 3.Can know from the explanation of Fig. 3, Fig. 4 and preamble, pass in several light frequency compositions of interferometer 3, have only one can pass etalon 7 at most.
Can know from the explanation of Fig. 3, Fig. 4 and preamble, long through the chamber of tuning interferometer 3, can select finally to pass the frequency of the light wave of etalon 7 artificially.That is to say, can from light wave to be measured, select a monochromatic optical wave.This function is the basis of realizing spectral measurement.
Get into 2 ports of circulator 8 from the monochromatic optical wave of etalon 7 outgoing, from 3 port outgoing; Get into 1 port of circulator 9,, get into FBG10 from 2 port outgoing.FBG10 is a light belt resistance wave filter.In the present invention, the stopband of FBG10 and the frequency range of light wave to be measured stagger, and can not treat in the photometry spectrum any one frequency content and have an effect.
Light wave passes after the FBG10, is changed into electric signal by photodetector 11, ingoing power measurement module 13.Acting as of power measurement module 13: calculate luminous power from electric signal; Sampling also stores the luminous power data.
In the present invention, the chamber of interferometer 3 is long by tuning continuously, and its transmitted spectrum also moves continuously.Can know that from the explanation of Fig. 3, Fig. 4 and preamble in a tuning cycle, different frequency components is passed system in different time in the light wave to be measured, by power measurement module 13 measured and records.So, include the power information of the light wave of different wave length in the data that power measurement module obtains.
For a spectrometric instrument, be not enough just only with the monochromatic optical wave separating and measuring in the spectrum to be measured, also must be able to judge the frequency of current measured light wave.See intuitively, can calculate the light frequency of the current light wave that passes through through the chamber length of stellar interferometer 3.But, because the variable quantity of chamber length is very little, can not obtain enough accurate the measurement, so the invention provides a stabilized light 5 as the means of judging current sampled light frequency.
The frequency stabilization mechanism that stabilized light 5 is adopted is PDH (Pound-Drever-Hall) method.In the PDH frequency-stabilizing method, a longitudinal mode that must adopt etalon is as the frequency stabilization benchmark.
In the present invention, adopt the frequency stabilization benchmark of certain longitudinal mode of etalon 7 as stabilized light 5.Strictly speaking, etalon 7 is used in combination with stabilized light 5 and just constitutes a complete stabilized light.Etalon 7 also has other function (with the interferometer 3 common frequency selection functions that realize), so so-called stabilized light 5 among the present invention is meant and removes etalon rest parts afterwards in the complete stabilized light but in the present invention.
In addition, the so-called frequency stabilization light wave of PDH method output is actually a light wave of doing wavelength-modulated with very little amplitude.
The light wave that stabilized light 5 sends is through coupling mechanism 6, and a part of luminous power is distributed to coupling mechanism 2, is used to judge the spectral shift amount of interferometer 3, and another part luminous power is distributed to the frequency stabilization backfeed loop.This loop comprises circulator 8, etalon 7, circulator 4.Light wave gets into from 1 port of circulator 8, and the output of 2 ports gets into etalon 7 then, and the light wave that passes etalon 7 gets into 2 ports of circulator 4, from the output of 3 ports, feeds back to stabilized light 5, and the error signal of frequency stabilization is provided.
The demodulation that utilizes stabilized light 5 to realize among the present invention to interferometer 3 transmission spectrum translational movements.Its course of work is: the light wave that stabilized light 5 sends is superimposed through coupling mechanism 2 and light wave to be measured, and together through interferometer 3, gets into 1 port of circulator 4; From the output of 2 ports, pass etalon 7, get into 2 ports of circulator 8; Export from 3 ports; Get into 1 port of circulator 9,, arrive FBG10 from the output of 2 ports.FBG10 is a band resistance optical filter, lets light wave to be measured pass through, and the light wave that stabilized light 5 is sent reflects.Stabilized light 5 from the output of 3 ports, is converted into electric signal by photodetection circuit 12 by 2 ports of FBG10 reflection back entering circulator 9, last input wavelength demodulation module 14.Acting as of Wavelength demodulation module 14: calculate the luminous power after light wave that stabilized light 5 sent passes total system from electric signal; Sampling is also preserved the luminous power data; Demodulation obtains wavelength data from the luminous power data.The principle narration of demodulation as follows.
Because the frequency of stabilized light 5 is stable, if the transmission spectrum generation translation of interferometer 3, this light wave is certain to produce corresponding variation after passing interferometer 3 so.Through resolving this variation, can learn the spectral shift amount of interferometer 3 in theory.But, consider that the fineness of interferometer 3 is very high, the shape of spectrum is very sharp-pointed, in the process of spectral shift, when the wavelength of stabilized light 5 is not aimed at certain longitudinal mode, does not almost have luminous power can pass interferometer 3, has increased a lot of difficulties to detection.
In order to let stabilized light 5 after passing interferometer 3, can also keep more luminous power, must reduce the fineness of interferometer 3, make its transmitted spectrum become more smooth.Yet in order to realize the frequency selection function, interferometer 3 needs very high fineness again.So, select the light frequency and the spectral range to be measured of stabilized light 5 to stagger, corresponding, interferometer 3 has higher fineness in spectral range to be measured, and near the wave band stabilized light 5 has lower fineness.In order to achieve this end, two end mirrors of interferometer 3 have different reflectivity in different wavelengths, and are as shown in Figure 5:
Fig. 5 (a) is the reflectivity of the end mirror of interferometer 3, R
1Be the reflectivity of spectral measurement ranges, be in close proximity to 1, R
2It is the reflectivity of stabilized light place wave band; Fig. 5 (b) is the pairing resonator cavity power of the different reflectivity transmission spectrum of different-waveband; Fig. 5 (c) is the spectrum of stabilized light 5.Should note the light wave that is actually a wavelength-modulated that stabilized light 5 is exported, its modulation amplitude approximates the longitudinal mode width D of etalon 7.In Fig. 5 and since the range spans of drawing a lot of Free Spectral Ranges, so the spectrum of stabilized light 5 is plotted as a fixing narrow spectrum.
The method of translational movement of transmission spectrum that demodulates interferometer 3 through stabilized light 5 is as shown in Figure 6.
Fig. 6 (a) is that longitudinal mode that is used for the light source frequency stabilization in the transmitted spectrum of etalon 7; Fig. 6 (b) is that the light wave of the wavelength Sine Modulated sent of stabilized light 5 is through suffered amplitude modulation(PAM) behind this longitudinal mode; Fig. 6 (c) is the transmitted spectrum of the antiradar reflectivity wave band of interferometer 3, and wherein solid line, dotted line, dot-and-dash line are represented three different transmission spectrums of translational movement respectively; Fig. 6 (d) is the amplitude modulation(PAM) of light wave through receiving after the interferometer 3 of wavelength Sine Modulated; Fig. 6 (e) is the light wave of wavelength Sine Modulated.
Of preamble, the present invention makes the transmitted spectrum generation translation of interferometer 3 through the chamber length of tuning interferometer 3.When the sharp-pointed transmission spectrum generation translation of high reflectance wave band, the mild transmission spectrum of antiradar reflectivity wave band also can the identical value of translation.So, the translation of measuring antiradar reflectivity wave band transmission spectrum, the spectral components that just can instead release which frequency can pass interferometer 3 and etalon 7.
Among the present invention, the light wave of a wavelength-modulated of stabilized light 5 outputs.So-called wavelength-modulated is meant that the light frequency of light wave changes according to certain rule in time, such as modal sinusoidal form.When the light wave of wavelength-modulated passes an optical filter, can be applied an amplitude modulation(PAM) by the transmitted spectrum of wave filter.This is because when light source is modulated to certain wavelength, just in time aim at the bigger point of transmitance in the transmitted spectrum, and when being modulated onto another wavelength, aim at the less point of transmitance in the transmitted spectrum.So in the cycle, the luminous power of passing transmission spectrum also can back and forth change one time a wavelength-modulated, final effect has applied an amplitude modulation(PAM) again to Wavelength modulation spectroscopy exactly.Oscillating curve among the Fig. 6 (b) that is produced to the longitudinal mode curve among Fig. 6 (a) referring to the sinusoidal curve projection among Fig. 6 (e).
It can also be seen that from Fig. 6 the waveform of the amplitude modulation(PAM) that transmitted spectrum applied is along with light source is different with the relative position of transmitted spectrum and change.In fact simple, in the bigger place of transmitted spectrum slope ratio, the amplitude modulation(PAM) that applies is just bigger, and vice versa.As three the transmission spectrum curves of the sinusoidal curve projection among Fig. 6 (e) in Fig. 6 (c) three different curves of cyclical fluctuations among Fig. 6 (b) of producing respectively.
From Fig. 6 (c), (d), (e) can find out; Antiradar reflectivity wave band at interferometer 3; When the transmitted spectrum translation (transmitted spectrum that only drawn among the figure is in three different positions, in order to represent translation), the wavelength-modulated light wave that stabilized light 5 sends has been aimed at the diverse location of transmitted spectrum; The phase place of the am signals of output, amplitude, frequency content all can be different, can be finally inversed by very much the spectral shift amount of resonator cavity from these information.
The frequency stabilization light wave also will pass through etalon 7 through after the interferometer 3, also can receive the modulation of etalon 7 again, like Fig. 6 (a), (b), (e) shown in.Can know that according to theoretical analysis the light wave of wavelength-modulated passes the total amplitude modulation(PAM) that receives after two resonator cavitys and is equivalent to their product of effect separately.Because the Free Spectral Range of two resonator cavitys is slightly different, can become addition through the relation that the computing of taking the logarithm will be multiplied each other, utilize means such as locking amplification mutually that both are separated then.
Wherein the front/rear end of electro-optic crystal 4 is coated with highly reflecting films, constitutes the F-P interferometer.The upper and lower surfaces of electro-optic crystal 4 posts electrode 5, through applying the refractive index that voltage changes material, thereby changes the light path in the resonator cavity.The voltage signal that is applied is as shown in Figure 8.As can be seen from Figure 8, the long time dependent function in chamber is the stack of a sine function and linear function.The slope of linear function equals the maximal value of sine function slope, so periodically to occur slope on the curve be 0 point.In design, these slopes are 0 some respective frequencies sampled point.Design is to consider that the fineness of two resonator cavitys is all very high like this, and chamber longitudinal mode width D is very little.If adopt linear sweep simply, then in the process of scanning, the time that both overlap is too of short duration.If with rate scanning very slowly, the time that then causes again testing is oversize.Therefore, the scanning form that the present invention adopts is longer in the SF place residence time, and at other local rate scanning faster of using, has solved this problem.
The foregoing description only is explanation technical conceive of the present invention and characteristics, and its purpose is to let the personage who is familiar with this technology can understand content of the present invention and enforcement according to this, can not limit protection scope of the present invention with this.All equivalences that spirit is done according to the present invention change or modify, and all should be encompassed within protection scope of the present invention.
Claims (8)
1. optical frequency territory vernier method spectrometer is characterized in that: comprising:
Incident collimation lens (1) is used for incident light to be measured is coupled into optical fiber;
Tunable F-P interferometer (3), it is selecting part to pass through from said incident collimation lens light wave through tuning its chamber length;
F-P etalon (7) is used for extracting the light wave from said tunable F-P interferometer (3) CF;
Be used to isolate catoptrical first fiber optical circulator (4), be positioned between tunable F-P interferometer (3) and the F-P etalon (7), be used for receiving light wave from tunable F-P interferometer (3);
Second fiber optical circulator (9) transmits light wave between this second fiber optical circulator (9) input port and the said F-P etalon (7);
First Electro-Optical Sensor Set (11) is connected to said second fiber optical circulator (9) first output ports, is used for light wave is converted into electric signal;
Power measurement module (13) is calculated luminous power according to the electric signal from first Electro-Optical Sensor Set (11), and sampling also stores the luminous power data;
Second Electro-Optical Sensor Set (12) is connected to said second fiber optical circulator (9) second output ports, is used for light wave is converted into electric signal;
Wavelength demodulation module (14), according to the luminous power of calculating from the electric signal of second Electro-Optical Sensor Set (12) after light wave that stabilized light (5) sent passes total system, the luminous power data are also preserved in sampling, and demodulation obtains wavelength data from the luminous power data.
2. optical frequency according to claim 1 territory vernier method spectrometer is characterized in that: two end mirrors have different reflectivity in different wavelengths in the said tunable F-P interferometer (3).
3. optical frequency according to claim 1 and 2 territory vernier method spectrometer is characterized in that: also comprise:
Stabilized light (5) receives the light wave from the 3rd port transmission in said first fiber optical circulator (4), and the frequency stabilization benchmark light wave that this stabilized light (5) sends is coupled into optical fiber through coupling mechanism (6) with from the light wave of incident collimation lens (1);
First fiber coupler (2), the light wave that stabilized light (5) sends is superimposed through coupling mechanism (2) and light wave to be measured, and together through interferometer (3);
Fiber Bragg Grating FBG (10) is positioned between said second fiber optical circulator (9) and first Electro-Optical Sensor Set (11), will reflect from the light wave that send stabilized light (5), and the frequency range of its stopband and light wave to be measured staggers.
4. optical frequency according to claim 3 territory vernier method spectrometer is characterized in that: the light frequency of said stabilized light (5) and the scope of spectrum to be measured stagger.
5. optical frequency according to claim 1 and 2 territory vernier method spectrometer is characterized in that:
Stabilized light (5) is used to provide a frequency stabilization benchmark light wave;
The 3rd fiber optical circulator (8); Its 1st port receives said frequency stabilization benchmark light wave; The 3rd fiber optical circulator (8) the 2nd port and said F-P etalon (7) transmission light wave, the 3rd fiber optical circulator (8) the 3rd port and said second fiber optical circulator (9) the 1st port transmission light wave;
Fiber Bragg Grating FBG (10) is positioned between said second fiber optical circulator (9) and the Electro-Optical Sensor Set (11), will reflect from the light wave that send stabilized light (5), and the frequency range of its stopband and light wave to be measured staggers.
6. optical frequency according to claim 5 territory vernier method spectrometer is characterized in that: the light frequency of said stabilized light (5) and the scope of spectrum to be measured stagger.
7. optical frequency according to claim 1 and 2 territory vernier method spectrometer is characterized in that: also comprise:
Stabilized light (5) is used to provide a frequency stabilization benchmark light wave;
Second fiber coupler (6), being used for the wavelength-division of frequency stabilization reference light is two-way;
First fiber coupler (2), the light wave that stabilized light (5) sends is superimposed through first fiber coupler (2) and light wave to be measured, and together through interferometer (3);
The 3rd fiber optical circulator (8); Its 1st port receives the frequency stabilization benchmark light wave from second fiber coupler (6); The 3rd fiber optical circulator (8) the 2nd port and said F-P etalon (7) transmission light wave, the 3rd fiber optical circulator (8) the 3rd port and said second fiber optical circulator (9) the 1st port transmission light wave; First Electro-Optical Sensor Set (11) is connected to said second fiber optical circulator (9) first output ports, is used for light wave is converted into electric signal;
Second Electro-Optical Sensor Set (12) is connected to said second fiber optical circulator (9) second output ports, is used for light wave is converted into electric signal;
Fiber Bragg Grating FBG (10) is positioned between said second fiber optical circulator (9) and the Electro-Optical Sensor Set (11), will reflect from the light wave that send stabilized light (5), and the frequency range of its stopband and light wave to be measured staggers.
8. optical frequency according to claim 7 territory vernier method spectrometer is characterized in that: the light frequency and the spectral range to be measured of said selection stabilized light (5) stagger.
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| CN113358037A (en) * | 2021-08-10 | 2021-09-07 | 中国计量科学研究院 | Laser displacement measuring device and method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113358037A (en) * | 2021-08-10 | 2021-09-07 | 中国计量科学研究院 | Laser displacement measuring device and method |
| CN113358037B (en) * | 2021-08-10 | 2021-11-09 | 中国计量科学研究院 | Laser displacement measuring device and method |
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