CN202158903U - Etalon based wavemeter - Google Patents

Abstract

The utility model provides an Etalon based wavemeter, comprising an optical path portion, a circuit and a computer, wherein the optical path portion comprises a spectrometer, a collimator and N Etalons having different states, the Etalons have a same amplitude reflection coefficient r and two same parameters selected from refractive index n, surface spacing l and incident angle theta, and the other parameter except the two same parameters is selected from N different values, forming the Etalons having N different states. After an input laser passes through the spectrometer, N paths of light beams enter into the Etalons respectively, and the output optical path of each Etalon is provided with a PD. The other path of light beam is a reference light, directly entering into a corresponding PD, and the PD is connected with the computer via an amplification acquisition circuit. After the wavemeter is used, a standard laser is used for scanning each Etalon with a certain step, generates a transmission efficiency data calibration table and stores the same, the computer compares and calculates a laser transmission efficiency to be measured with the calibration table, and then directly displays a measured result. The wavemeter can realize high accuracy and high speed measurement of C+L wave band laser wavelength, and is simple in structure and low in cost.

Description

Wavemeter based on Etalon

(1) technical field

The utility model relates to the field of measuring technique of optical maser wavelength, is specially a kind of wavemeter based on Etalon.

(2) background technology

Along with the high speed development in fields such as optical fiber communication and delicate metering, optical maser wavelength (frequency) is as a kind of important parameters, and its Research on Measuring Technology obtains extensive concern.Laser Measurement wavelength (frequency) is one of key factor of decision association area development progress quickly and accurately.

The measuring technique of existing optical wavelength and wavemeter sweep velocity, measuring accuracy all are difficult to meet the demands, and are difficult to use in the optical maser wavelength of measuring in the high-power scope.The wavemeter measuring speed is slow, complex structure, build is big, cost is high, hinders its application in industries such as communications.

Etalon is a kind of optical instrument; Have two parallel reflecting surfaces, form the interference of light owing to light beam repeatedly reflects on two surfaces, the light transmissioning efficiency (T) that this interference produces is the periodic function of light wavelength/frequency; Available Airy function representes, suc as formula 1 with shown in the formula 2.

$T=\frac{1}{1+F{\sin }^2(\mathrm{\δ}/2)},$ $F=\frac{4R}{{(1-R)}^2}---\left(1\right)$

$\mathrm{\δ}=\frac{4\mathrm{\π}\mathrm{nl}\cos \mathrm{\θ}}{\mathrm{\λ}}---\left(2\right)$

R=r in the formula ², r is an amplitude reflectance, and n is refractive index, l is the Etalon spacing of reflecting plane, i.e. and the spacing on two surfaces, λ is the optical maser wavelength of incident, θ is an incident angle.

Transition function formula (1) is a periodic function, and the frequency interval between crest and crest is:

$\mathrm{\Δ\ν}=\frac{c}{2\mathrm{nl}\cos \mathrm{\θ}}---\left(3\right)$

This value is defined as free spectral range, in order vividerly to show periodically, below is referred to as frequency period.

Through measuring transfer efficiency T; Can use function (1) and (2) to calculate the wavelength X of laser beam, but this formula is a periodic function, that is to say; The corresponding a plurality of wavelength/frequency of same transfer efficiency, this moment is not if there are other decision conditions can't confirm the optical maser wavelength of its actual input.So be difficult to adopt the method design wavelength meter of measuring the Etalon transfer efficiency.

(3) utility model content

The purpose of the utility model is to disclose a kind of wavemeter based on Etalon.

The wavemeter based on Etalon of the utility model design comprises light path part, circuit and computing machine; Light path part comprises the Etalon of spectrometer, a collimating apparatus and N different conditions; The amplitude reflectance r of each Etalon is identical; Identical and other 1 parameter of 2 parameters among refractive index n, surface spacing l and the incident angle θ is selected N different value, constitutes the Etalon of N kind different conditions.Make that the frequency response curve of transfer efficiency of each Etalon is different; Promptly the incident laser by different wavelengths/frequency obtains the different transfer efficiency of N group; Thereby after measuring the transfer efficiency value of testing laser, can uniquely confirm a correct wavelength/frequency through checking transfer efficiency data calibration table.Continuous or the pulse laser of input inserts spectrometer, is divided into the multichannel light beam, and N road light beam gets into each Etalon respectively after each collimating apparatus, photodiode is respectively arranged on the output light path of each Etalon.Another road light beam is a reference light, directly gets into corresponding with it photodiode, and photodiode connects the amplification Acquisition Circuit, amplifies Acquisition Circuit and connects computing machine, and computing machine is connected to display screen.

Said laser is continuous laser or pulse laser.

Photodiode converts the light signal that receives into electric signal and sends into computing machine through amplifying Acquisition Circuit.The transfer efficiency of COMPUTER CALCULATION Etalon and storage transmission efficiency data correction card.Amplify the amplification of Acquisition Circuit realization data acquisition and electric signal, for Computer Processing provides signal.The operation of computer control wavemeter, deal with data and demonstration measurement result.Computing machine is the transfer efficiency of each Etalon with each electrical signal conversion of testing laser gained, relatively calculates with the storage data, and the wavelength value of the continuous or pulse laser that promptly obtains importing is sent to display screen simultaneously and directly shows.

The ratio of the electric signal magnitude of voltage of the electric signal magnitude of voltage of the photodiode of each light beam through Etalon and the photodiode of reference light is the transfer efficiency value of each light beam Etalon.

After the wavemeter assembling is accomplished; Employing standard tunable laser is in test specification, and f scans with step delta, 0.2GHz≤Δ f≤1GHz; The transfer efficiency of the Etalon of the different conditions of measurement different frequency laser; Obtain N group transfer efficiency value, thereby generate the transfer efficiency data calibration table of the Etalon of the corresponding different conditions in the whole test frequency range, and be stored in the computing machine.

Above-mentioned wavemeter based on Etalon; Also can only adopt one or several Etalon assembly parameter regulating part; Make 2 parameters among refractive index n, surface spacing l and the incident angle θ of this Etalon keep constant; Adjustment parameter regulation part makes other 1 parameter select N different value, obtains the Etalon of N kind different conditions.

In order to obtain the Etalon of different conditions, for the Etalon of clearance, fixing refractive index n and incident angle θ are arranged, the regulating part that changes its surface spacing is installed; For the Etalon of gas or liquid filling cavity, fixing surface spacing l is arranged, heat or the regulating part of pressure or electronic technology of the refractive index n of Etalon is installed; For solid etalon, fixing refractive index n and surface spacing l are arranged, mechanical hook-up or the electronic installation of the incident angle θ of adjustment input laser is installed.

Because the transfer efficiency of Etalon has periodically the frequency/wavelength of laser, thus the key of this wavemeter be tell certain transfer efficiency value corresponding be the frequency in which cycle.The periodicity of single Etalon exists; And the Etalon of N kind different conditions; Frequency period is different, and the system of their compositions has avoided the transfer efficiency array to have periodic problem basically so, thereby has satisfied the condition of every group of unique corresponding wavelength of transfer efficiency numerical value.

The utility model based on the advantage of the wavemeter of Etalon is: 1, superior performance, and precision is high, is applicable to research and development, production and the communications field of optical device; 2, compare with existing optical wavelengthmeter, guarantee high precision and high-resolution while, sweep velocity more has very large raising; 3, small, simple in structure and cost is relatively low, have high cost performance.

(4) description of drawings

Fig. 1 is this structural representation based on the wavemeter embodiment of Etalon;

Fig. 2 is this based on different Etalon transfer efficiency of 4 incident angles among the wavemeter embodiment of Etalon and the graph of relation between frequency;

Fig. 3 is 186310GHz based on 4 different Etalon of incident angle among the wavemeter embodiment of Etalon playing dot frequency for this, the graph of relation when frequency increment is 50GHz between transfer efficiency and frequency.

(5) embodiment

This structure based on the wavemeter embodiment of Etalon is as shown in Figure 1; Comprise light path part, circuit and computing machine; Light path part comprises spectrometer, collimating apparatus and 4 Etalon that amplitude reflectance r equates, the major parameter of each Etalon is refractive index n, reflecting surface spacing l and incident angle θ.The parameter n of 4 Etalon is identical with l, but incident angle θ is different.Input continuously or pulse laser insert spectrometer, be divided into 8 road light beams, wherein 5 the tunnel respectively through 5 collimating apparatuss after, one tunnel light as a reference directly gets into the photodiode PD on the light path, other 4 the tunnel each with different incident angle θ entering each Etalon: θ ₁=0, θ ₂=1.97 °, θ ₃=5.36 °, θ ₄=5.48 °, constitute Etalon1, Etalon2, Etalon3 and Etalon4.Photodiode PD is respectively arranged on the output light path of each Etalon, and 5 photodiode PD connect the amplification Acquisition Circuit, amplify Acquisition Circuit and connect computing machine, and computing machine is connected to display screen.This routine used computing machine is a PC.Each photodiode PD converts the light signal that receives into electric signal and sends into computing machine through amplifying Acquisition Circuit.

Photodiode converts the light signal that receives into electric signal and sends into computing machine through amplifying Acquisition Circuit.The transfer efficiency of COMPUTER CALCULATION Etalon and storage transmission efficiency data correction card.Amplify the amplification of Acquisition Circuit realization data acquisition and electric signal, for Computer Processing provides signal.The operation of computer control wavemeter, deal with data and demonstration measurement result.Computing machine is the transfer efficiency of each Etalon with each electrical signal conversion of testing laser gained, relatively calculates with the storage data, and the wavelength value of the continuous or pulse laser that promptly obtains importing is sent to display screen simultaneously and directly shows.

The ratio of the electric signal magnitude of voltage of the electric signal magnitude of voltage of the photodiode of each light beam through Etalon and the photodiode of reference light is the transfer efficiency value of each light beam Etalon.

After the wavemeter assembling is accomplished; In test specification, use the transfer efficiency of standard tunable laser with the step scan measurement different frequency laser of 1GHz, the frequency response curve of the transfer efficiency of each Etalon that parameter θ is different is different; As shown in Figure 2, the correspondent frequency cycle is respectively A ₁50GHz, A ₂50.030GHz, A ₃50.220GHz, A ₄50.230GHz.The transfer efficiency data that simultaneously scanning obtained are stored in the computing machine as correction card.Fig. 3 is 186310 being dot frequency, is the frequency response curve of the frequency increment transfer efficiency of drawing with 50GHz.

During measurement, testing laser is with above-mentioned θ ₁, θ ₂, θ ₃, θ ₄Each Etalon of incident, computing machine will import laser and pass through the transfer efficiency of the electrical signal conversion of each Etalon generation for each Etalon, relatively calculate with the storage data, and the wavelength value of the continuous or pulse laser that promptly obtains importing can be delivered to display screen simultaneously and directly show.

The major parameter of this routine wavemeter is following:

Wavelength coverage	1525～1610nm
		Absolute precision	±1.0pm
Wavelength resolution	±0.1pm
		Display resolution	0.0001nm
Sample rate	100Hz
		Power bracket	-35±20dBm
The power precision	±0.5dB
		The power flatness	±0.5dB

Select suitable Etalon parameter combinations; Make resolution characteristic reach requirement; Can realize the optical maser wavelength/frequency measurement of whole light-wave band so in theory; But the working range of actual each device of medium wavelength meter is like the linearity of devices such as photodiode PD, spectrometer and the actual measurement range that precision affects wavemeter.

The foregoing description is merely concrete example of purpose, technical scheme and beneficial effect further explain to the utility model, and the utility model is not to be defined in this.All any modifications of within the scope of disclosure of the utility model, being made, be equal to replacement, improvement etc., all be included within the protection domain of the utility model.

Claims (6)

1. based on the wavemeter of Etalon, it is characterized in that:

Comprise light path part, circuit and computing machine; Light path part comprises the Etalon of spectrometer, a collimating apparatus and N different conditions; The amplitude reflectance r of each Etalon is identical; Identical and other 1 parameter of 2 parameters among the refractive index n of N Etalon, surface spacing l and the incident angle θ is selected N different value, constitutes the Etalon of N kind different conditions; Continuous or the pulse laser of input inserts spectrometer, is divided into the multichannel light beam, and N road light beam gets into each Etalon respectively after each collimating apparatus, photodiode is respectively arranged on the output light path of each Etalon; Another road light beam is a reference light, directly gets into corresponding with it photodiode, and photodiode connects the amplification Acquisition Circuit, amplifies Acquisition Circuit and connects computing machine.

2. the wavemeter based on Etalon according to claim 1 is characterized in that:

Said laser is continuous laser or pulse laser.

3. the wavemeter based on Etalon according to claim 1 is characterized in that:

Said computing machine is connected to display screen.

4. according to each described wavemeter in the claim 1 to 3, it is characterized in that based on Etalon:

Said Etalon is the Etalon of clearance, and fixing refractive index n and incident angle θ are arranged, and the regulating part that changes its surface spacing is installed.

5. according to each described wavemeter in the claim 1 to 3, it is characterized in that based on Etalon:

Said Etalon is the Etalon of gas or liquid filling cavity, and fixing surface spacing l is arranged, and heat or the regulating part of pressure or electronic technology of the refractive index n of Etalon is installed.

6. according to each described wavemeter in the claim 1 to 3, it is characterized in that based on Etalon:

Said Etalon is solid etalon, and fixing refractive index n and surface spacing l are arranged, and mechanical hook-up or the electronic installation of the incident angle θ of adjustment input laser is installed.

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