CN111338021A - Preparation method of electric control fiber grating - Google Patents

Abstract

The invention discloses a preparation method of an electric control fiber grating system, which comprises the following steps of S1: preprocessing an optical fiber to manufacture and cover an electromagnetic induction material layer on a normal grating modulation area of the optical fiber distributed along the axial direction to form an optical fiber grating element; step S2: and adopting an alternating magnetic field to act with the electromagnetic induction material layer, so that the electromagnetic induction material layer generates heat to further heat the normal grating modulation area of the optical fiber, thereby changing the refractive index of the normal grating modulation area and forming the optical fiber grating. The preparation method does not need expensive instrument equipment, greatly saves equipment cost, simplifies the preparation process, ensures that the fiber grating element can be heated only when being placed in an alternating magnetic field, greatly improves the safety factor, can modulate the writing spectrum of the fiber grating in real time, has higher yield and controllable preparation time, is beneficial to realizing mass production, and can recycle the fiber grating element for preparing different fiber gratings.

Description

A kind of preparation method of electronically controlled fiber grating

technical field

The invention relates to optical fiber sensing technology, in particular to a preparation method of an electronically controlled optical fiber grating.

Background technique

Fiber grating has the advantages of small size, low splicing loss, full compatibility with optical fibers, and can be embedded in smart materials, and its resonant wavelength is sensitive to changes in external environments such as temperature, strain, refractive index, concentration, etc. The field of sensing has been widely used. The existing fiber grating preparation methods mainly include CO2 laser etching method, arc discharge method, HF wet etching, periodic deformation, amplitude mask method and femtosecond laser direct writing method. As an illustration, the more typical processing methods are as follows:

CO2 laser etching method: a single laser pulse passes through the focusing mirror and is irradiated on the optical fiber, and an imaging system is set up on the optical fiber to observe whether the light is deformed during the grating writing process. The grating is written point by point with a laser on one side, and is controlled by a switch The laser is turned on and off, and after irradiating one position, the next gate area is written by moving the fiber position axially. This writing technology has obvious advantages. It does not need to sensitize the optical fiber, and the laser movement trajectory can be easily controlled by the computer. However, there are certain defects. During the writing process, the on-off of the laser and the displacement of the optical fiber are operated by the computer, and it is difficult to guarantee the focused laser. The accuracy of each alignment of the light spot and the fiber is not conducive to the stability and consistency of grating writing.

Amplitude mask method: The key to this method lies in the amplitude mask. When the ultraviolet light transmits the amplitude mask to laterally expose the optical fiber, it can induce periodic refractive index changes inside the optical fiber to form a long period grating structure. Due to the large period of the long-period fiber grating, the manufacturing accuracy of the reticle can be ensured, so it is easy to obtain a grating with high consistency that meets the spectral requirements. Therefore, this method has been used and is in the mainstream position of the preparation process. However, this method also has many drawbacks. First of all, a photosensitive fiber must be used, and the finished product is unstable at high temperature. The LPG must be annealed to ensure that it can be used at high temperature. The cycle is fixed, and there is no way to flexibly adjust the cycle length according to the demand, which greatly increases the preparation cost.

Femtosecond laser direct writing method: the femtosecond laser focus focused by the objective lens is incident into the germanium-doped fiber core, the refractive index of the area irradiated by the laser will increase, and the fiber will be moved parallel to form a periodicity inside the glass the waveguide structure. Using the femtosecond laser to directly write the fiber grating, no phase (amplitude) mask is needed, and any type of fiber grating can be prepared simply by controlling the relative position of the spot focus on the fiber core, but it is used to prepare long periodicity. The fiber grating process is very complex, difficult to operate, and the cost is high.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned shortcomings of the prior art, the present invention provides a preparation method of an electronically controlled fiber grating system, which does not require the use of expensive equipment, greatly saves equipment costs, and simplifies the preparation process. It is only heated in the magnetic field, the safety factor is greatly improved, the writing spectrum of the fiber grating can be modulated in real time, the yield is higher, and the preparation time is controllable, which is conducive to the realization of mass production, and the fiber grating components can be recycled and reused to prepare different fiber gratings.

The technical problem to be solved by this invention is realized through the following technical solutions:

A preparation method of an electronically controlled fiber grating, comprising the following steps:

Step S1: pre-processing the optical fiber, so as to fabricate and cover an electromagnetic induction material layer on the normal position grating modulation area distributed along the axial direction of the optical fiber to form a fiber grating element;

Step S2: using an alternating magnetic field to interact with the electromagnetic induction material layer to heat the electromagnetic induction material layer and then heat the normal grating modulation region of the optical fiber to change the refraction of the normal grating modulation region rate to form a fiber grating.

Further, after step S2, it also includes the following steps:

Step S3: modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum by controlling the alternating magnetic field.

Further, step S3 includes the following steps:

Step S3.1: coupling the detection beam into the fiber grating element;

Step S3.2: receiving the light beam transmitted or reflected from the fiber grating element to obtain the real-time writing spectrum of the fiber grating;

Step S3.3: Control the alternating magnetic field to modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum.

Further, by controlling the magnetic field strength and/or the alternating frequency of the alternating magnetic field, the resonant peak wavelength of the fiber grating, the loss peak strength and the preparation modulation time are at least the same.

Further, the alternating magnetic field is controlled by controlling the alternating current that generates the alternating magnetic field.

Further, by controlling the current and voltage intensity and/or the alternating frequency of the alternating current, at least one of the resonance peak wavelength, loss peak intensity and preparation modulation time of the fiber grating is modulated.

Further, step S1 includes the following steps:

Step S1.1: According to the phase matching formula, determine the position of the normal position grating modulation region of the required fiber grating along the axial direction of the fiber;

Step S1.2: fabricating a layer covering the electromagnetic induction material on the normal grating modulation area distributed along the axial direction of the optical fiber.

Further, step S1.2 includes the following steps:

Step S1.2.1: fabricating and covering an insulating and heat insulating material layer on the surface of the optical fiber;

Step S1.2.2: peeling off the insulating and heat-insulating material layer covering the normal-position grating modulation area, so that the normal-position grating modulation area is exposed from the insulating and heat-insulating material layer;

Step S1.2.3: forming a layer covering the electromagnetic induction material on the exposed normal-position grating modulation area.

Further, step S1.2 includes the following steps:

Step S1.2.1: making a coating material layer on the surface of the optical fiber;

Step S1.2.2: peel off the coating material layer covering the normal-position grating modulation area, so that the normal-position grating modulation area is exposed from the coating material layer;

Step S1.2.3: forming a layer covering the electromagnetic induction material on the exposed normal-position grating modulation area;

Step S1.2.4: peel off the remaining coating material layer.

Further, step S1.2 includes the following steps:

Step S1.2.1: making a layer covering the electromagnetic induction material on the surface of the optical fiber;

Step S1.2.2: fabricating and covering a photosensitive material layer on the surface of the electromagnetic induction material layer;

Step S1.2.3: exposing and developing the photosensitive material layer, so that the electromagnetic induction material layer covering the outside of the normal grating modulation area is exposed from the photosensitive material layer;

Step S1.2.4: Etch the exposed electromagnetic induction material layer.

The invention has the following beneficial effects: the preparation method uses electromagnetic induction material layers with different distribution rules to conduct electromagnetic induction, and different fiber gratings can be prepared without using expensive instruments and equipment, which greatly saves the equipment cost and simplifies the preparation process. , the fiber grating element will be heated only when it is placed in the alternating magnetic field, the safety factor is greatly improved, the writing spectrum of the fiber grating can be modulated in real time, the yield is higher, and the preparation time is controllable, which is conducive to the realization of mass production, and can be Recycle and reuse.

Description of drawings

Fig. 1 is the step block diagram of the preparation method of the electronically controlled fiber grating provided by the present invention;

Fig. 2 is the schematic diagram of the fiber grating element of the long periodic fiber grating provided by the present invention;

Fig. 3 is the transmission spectrum diagram of the long periodic fiber grating shown in Fig. 2;

4 is a schematic diagram of a fiber grating element of a short periodic fiber grating provided by the present invention;

Fig. 5 is the reflection spectrum diagram of the short periodic fiber grating shown in Fig. 4;

6 is a schematic diagram of a fiber grating element of an aperiodic fiber grating provided by the present invention;

Fig. 7 is the reflection spectrum diagram of the aperiodic fiber grating shown in Fig. 6;

8 is a schematic diagram of a preparation system of an electronically controlled fiber grating provided by the present invention;

9 is a schematic diagram of another preparation system of the electronically controlled fiber grating provided by the present invention;

10 is a block diagram of steps of a preprocessing method for an electronically controlled fiber grating provided by the present invention;

Fig. 11 is a block diagram of step S1.2 in the preprocessing method of the electronically controlled fiber grating shown in Fig. 10;

Fig. 12 is a block diagram of another step S1.2 in the preprocessing method of the electronically controlled fiber grating shown in Fig. 10;

FIG. 13 is a block diagram of another step S1.2 in the preprocessing method of the electronically controlled fiber grating shown in FIG. 10 .

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

Example 1

As shown in Figures 1, 2, 4 and 6, a preparation method of an electronically controlled fiber grating comprises the following steps:

Step S1 : preprocessing the optical fiber 11 to fabricate and cover an electromagnetic induction material layer 12 on the normal position grating modulation area distributed along the axial direction of the optical fiber 11 to form the optical fiber grating element 1 .

In this step S1, the electromagnetic induction material layer 12 can be made of metals such as iron, nickel, cobalt, or oxides or alloys containing such metals, such as iron oxide, silicon steel, stainless steel, iron-cobalt alloy, nickel-cobalt alloy, etc. , such metals, metal oxides and alloys have both good electrical conductivity and good magnetic permeability. In addition, rare earths or oxides or alloys containing rare earths can also be used to make the electromagnetic induction material layer 12 .

Step S2: using an alternating magnetic field to act on the electromagnetic induction material layer 12 to make the electromagnetic induction material layer 12 generate heat and then heat the normal grating modulation area of the optical fiber 11 to change the normal position grating modulation The refractive index of the region forms a fiber grating.

In this step S2, when the alternating magnetic field acts on the electromagnetic induction material layer 12, based on the principle of electromagnetic induction, a current eddy current can be formed inside the electromagnetic induction material layer 12, and the current eddy current has a thermal effect and can The electromagnetic induction material layer 12 is heated, and based on the optical fiber photothermal effect, the refractive index of the normal grating modulation region is changed under the heating of the electromagnetic induction material layer 12 to form the fiber grating.

Since the refractive index of the normal grating modulation region changes with its temperature, the writing spectrum of the fiber grating can be modulated by controlling the calorific value of the electromagnetic induction material layer 12 . Therefore, after step S2, the preparation method further includes:

Step S3: modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum by controlling the alternating magnetic field.

In this step S3, the purpose of controlling the alternating magnetic field can be achieved by controlling the alternating current that generates the alternating magnetic field, and the current voltage intensity and alternating frequency of the alternating current correspond to the alternating current, respectively. The magnetic field strength and alternating frequency of the magnetic field jointly determine the heat generation of the electromagnetic induction material layer 12, thereby determining the grating modulation amount of the normal grating modulation region, that is, the resonance peak wavelength and loss peak of the fiber grating intensity, and the preparation modulation time is negatively related to the current and voltage intensity and alternating frequency of the alternating current. less, and vice versa.

Therefore, the resonance peak wavelength and loss peak of the fiber grating can be modulated by controlling the current and voltage strength and/or the alternating frequency of the alternating current (ie, the magnetic field strength and/or the alternating frequency of the alternating magnetic field). At least one of intensity and preparation modulation time.

Specifically, in this step S3, the steps of modulating the real-time writing spectrum of the fiber grating into the required writing spectrum are as follows:

Step S3.1 : coupling the detection beam into the fiber grating element 1 .

In this step S3.1, the detection beam coupled into the fiber grating element 1 is preferably a supercontinuous broadband beam whose detection spectrum continuously covers a large wavelength range.

Step S3.2: Receive the light beam transmitted or reflected from the fiber grating element 1, and obtain the real-time writing spectrum of the fiber grating.

In this step S3.2, during the transmission process of the detection beam in the fiber grating element 1, when passing through the normal position grating modulation area, a part of the detection beam will be reflected by the fiber grating and return to the original path, forming a Reflect the beam to obtain a reflection spectrum, and another part of the detection beam can continue to transmit forward through the fiber grating to form a transmission beam to obtain a transmission spectrum, wherein the reflection spectrum and the transmission spectrum are complementary, and the complementary constitutes step S3. The spectrum of the detection beam in 1 coupled into the fiber grating element 1.

The real-time writing spectrum and the required writing spectrum of the fiber grating can be represented by the reflection spectrum or the transmission spectrum.

Step S3.3: Control the alternating magnetic field to modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum.

In this step S3.3, the real-time writing spectrum of the fiber grating is compared with the required writing spectrum. If they are the same, the modulation is ended. If they are different, the alternating magnetic field is controlled to change, and step S3 is repeated. .1-S3.3, until the real-time writing spectrum of the fiber grating is the same as the desired writing spectrum, end the modulation.

Since the refractive index of the normal grating modulation region changes with its temperature, the fiber grating is non-permanent. When the alternating magnetic field is removed, the temperature of the normal grating modulation region returns to normal. After that, the fiber grating will also disappear, and the fiber grating element 1 is equivalent to an ordinary fiber. Therefore, before each use, it is necessary to modulate the fiber grating element 1 to have all the The optical fiber grating needs to write the spectrum, and the alternating magnetic field cannot be removed during use. The fiber grating needs to be modulated while being used, so as to avoid the real-time change of the fiber grating caused by the temperature change of the normal-position grating modulation area. The writing spectrum deviates.

The preparation method can produce long periodic fiber grating, short periodic fiber grating or aperiodic fiber grating.

In a specific embodiment, as shown in FIG. 2 , the fiber grating is a long-period fiber grating, its grating period Λ=0.5mm, and the grating order is N. First, the long-periodicity is calculated by using the phase matching formula. The resonant wavelength position of the fiber grating is determined to determine the position of the normal grating modulation region periodically distributed along the axis of the fiber 11, and then N number of methods periodically distributed along the axis of the fiber 11 with 0.5mm The electromagnetic induction material layer 12 is covered on the position grating modulation area to obtain the fiber grating element 1, and then the alternating magnetic field is used to interact with the electromagnetic induction material layer 12 to perform the normal position grating modulation area Heating makes the fiber grating element 1 form a long-period fiber grating, and finally the real-time writing spectrum of the long-period fiber grating is modulated into a transmission spectrum as shown in FIG. 3 .

In another specific embodiment, as shown in FIG. 4 , the fiber grating is a short-period fiber grating with a grating period of Λ=0.1 mm and a grating order of N. The short period is calculated by using the phase matching formula. The position of the resonant wavelength of the optical fiber grating is determined to determine the position of the normal grating modulation region periodically distributed along the axial direction of the optical fiber 11, and then N number of periodically distributed along the axial direction of the optical fiber 11 at 0.1 mm The electromagnetic induction material layer 12 is covered on the normal grating modulation area to obtain the fiber grating element 1 , and then the alternating magnetic field is used to interact with the electromagnetic induction material layer 12 to adjust the normal position grating modulation area. Heating is performed to make the fiber grating element 1 form a short-period fiber grating, and finally the real-time writing spectrum of the short-period fiber grating is modulated into a reflection spectrum as shown in FIG. 5 .

In yet another specific embodiment, as shown in FIG. 6 , the fiber grating is an aperiodic fiber grating, and the aperiodic grating pitches are Λ1, Λ2, ... Λn in sequence, and the grating order is N. Similarly, First, use the phase matching formula to calculate the resonant wavelength position of the non-periodic fiber grating to determine the non-periodic distribution position of the normal-position grating modulation region along the axis of the fiber 11, and then The optical fiber 11 is fabricated to cover the electromagnetic induction material layer 12 on N normal-position grating modulation regions with aperiodic distribution of Λ1, Λ2, ... Λn in the axial direction, so as to obtain the fiber grating element 1, and then use the The alternating magnetic field acts on the electromagnetic induction material layer 12 to heat the normal-position grating modulation region to make the fiber grating element 1 form an aperiodic fiber grating, and finally the real-time optical fiber grating of the aperiodic fiber grating is formed. The spectral modulation is written as a reflectance spectrum as shown in Figure 7.

Embodiment 2

As shown in Figures 10, 2, 4 and 6, a preprocessing method for an electronically controlled fiber grating, which can be used as step S1 of the preparation method described in Embodiment 1, includes the following steps:

Step S1.1: According to the phase matching formula, determine the position along the axial direction of the optical fiber 11 of the normal-position grating modulation region of the required fiber grating.

In this step S1.1, according to the phase matching formula corresponding to the long periodic, short periodic or aperiodic fiber grating, the resonance peak position of the corresponding fiber grating can be calculated. The phase matching formula is common knowledge in the field, so this embodiment only uses a short periodic grating fiber for the following description:

The phase matching formula of short periodic grating fiber is m*λ _B =2*n _eff *Λ, where m is the grating order of the desired fiber grating, λ _B is the center reflection wavelength of the desired fiber grating, n _eff is the effective refractive index of the fiber core, and Λ is the grating period (grating pitch) of the desired fiber grating. According to the phase matching formula, when the grating period Λ and the grating order m of the desired fiber grating are determined, the center reflection wavelength λ _B of the desired fiber grating can be calculated, and conversely, when the desired fiber grating is determined In the case of the central reflection wavelength λ _B of , the relationship between the grating period Λ of the required fiber grating and the grating order m can be calculated.

Step S1.2: Fabricating and covering an electromagnetic induction material layer 12 on the normal grating modulation area distributed along the axial direction of the optical fiber 11 .

In a specific embodiment, as shown in Figure 11, step S1.2 includes the following steps:

Step S1.2.1: fabricate and cover the surface of the optical fiber 11 with an insulating and heat-insulating material layer.

In this step S1.2.1, the insulating and heat-insulating material layer may be, but is not limited to, organic materials such as rubber, silica gel, or plastic. Such organic materials have both good insulating ability and good heat-insulating ability.

Step S1.2.2: peel off the insulating and heat-insulating material layer covering the normal-position grating modulation region, so that the normal-position grating modulation region is exposed from the insulating and heat-insulating material layer.

In this step S1.2.2, the insulating and heat insulating material layer may be partially peeled off by means of cutting or CO2 laser etching.

Step S1.2.3: forming the electromagnetic induction material layer 12 on the exposed normal grating modulation area.

In this step S1.2.3, the electromagnetic induction material layer 12 may be fabricated by means of vacuum coating, magnetron sputtering or spraying. During fabrication, the electromagnetic induction material layer 12 can cover only the exposed normal grating modulation region, or simultaneously cover the exposed normal grating modulation region and the insulating and heat insulating material layer. Due to the insulating properties and heat insulating properties of the insulating and heat insulating material layer, neither the current nor the heat generated by the electromagnetic induction material layer 12 in the alternating magnetic field will spread out.

In another specific implementation, as shown in Figure 12, step S1.2 includes:

Step S1.2.1: fabricate a coating material layer on the surface of the optical fiber 11 .

In this step S1.2.1, the coating material layer needs to meet the requirement that the electromagnetic induction material layer 12 can be removed by a different solution, that is, there is a solution that can dissolve or corrode the coating material layer, The electromagnetic induction material layer 12 cannot be dissolved or corroded. For example, if the coating material layer is made of organic materials such as rubber, silica gel or plastic, it is easily dissolved by organic solvents, and metals such as iron, nickel, cobalt, etc. are used or contain The electromagnetic induction material layer 12 of such metal oxides or alloys is difficult to be dissolved by organic solvents.

Step S1.2.2: peel off the coating material layer covering the normal-position grating modulation region, so that the normal-position grating modulation region is exposed from the coating material layer.

In this step S1.2.2, the coating material layer can be partially peeled off by means of cutting or CO2 laser.

Step S1.2.3: forming the electromagnetic induction material layer 12 on the exposed normal grating modulation area.

In this step S1.2.3, the electromagnetic induction material layer 12 may be fabricated by means of vacuum coating, magnetron sputtering or spraying. During fabrication, the electromagnetic induction material layer 12 can either cover only the exposed normal grating modulation region, or simultaneously cover the exposed normal grating modulation region and the coating material layer.

Step S1.2.4: peel off the remaining coating material layer.

In this step S1.2.4, when the remaining coating material layer is peeled off, the electromagnetic induction material layer 12 covering it can be taken away together, leaving only the layer covering the normal grating modulation area. The electromagnetic induction material layer 12 .

As mentioned above, the organic solvent can dissolve the coating material layer made of organic materials such as rubber, silica gel or plastic, but it is difficult to dissolve the electromagnetic induction material layer 12. Therefore, in this step S1.2.4, the remaining organic solvent can be used to dissolve the coating material layer 12. The coating material layer is peeled off.

In yet another specific embodiment, as shown in Figure 13, step S1.2 includes:

Step S1.2.1: fabricate a layer 12 covering the electromagnetic induction material on the surface of the optical fiber 11 .

In this step S1.2.1, the electromagnetic induction material layer 12 may be fabricated by vacuum coating, magnetron sputtering, or spraying.

Step S1.2.2: forming a photosensitive material layer covering the surface of the electromagnetic induction material layer.

In this step S1.2.2, the photosensitive material layer may be a positive photoresist or a negative photoresist, which is fabricated by coating.

Step S1.2.3: Expose and develop the photosensitive material layer, so that the electromagnetic induction material layer 12 covering outside the normal grating modulation area is exposed from the photosensitive material layer.

In this step S1.2.3, ultraviolet light is used to expose the photosensitive material layer through a photolithography mask, and then the exposed part or the unexposed part of the photosensitive material layer is removed by a developing solution. The exposed part of the negative photoresist can be removed by the developer, and the unexposed part of the negative photoresist can be removed by the developer.

Step S1.2.4: Etching and removing the exposed electromagnetic induction material layer 12 .

In this step S1.2.4, if the electromagnetic induction material layer 12 is made of iron, nickel, cobalt and other metals or oxides or alloys containing such metals, the exposed electromagnetic induction material layer 12 can be etched with an acid solution. However, the remaining photosensitive material layer is difficult to be corroded by the acid solution.

Step S1.2.5: peel off the remaining photosensitive material layer.

In this step S1.2.5, the remaining photosensitive material layer can be peeled off by using an alkaline solution, and the electromagnetic induction material layer 12 using metals such as iron, nickel, cobalt, or oxides or alloys containing such metals is difficult to be affected by alkalis. Corrosive solution.

Embodiment 3

As shown in FIGS. 2 , 4 and 6 , a fiber grating element 1 includes an optical fiber 11 and an electromagnetic induction material layer 12 , and the electromagnetic induction material layer 12 prepares a normal-position grating modulation covering the optical fiber 11 distributed along the axial direction area.

The electromagnetic induction material layer 12 can be made of iron, nickel, cobalt and other metals or oxides or alloys containing such metals, such as iron oxide, silicon steel, stainless steel, iron-cobalt alloy, nickel-cobalt alloy, etc. Oxides and alloys have both good electrical conductivity and good magnetic permeability. In addition, rare earths or oxides or alloys containing rare earths can also be used to make the electromagnetic induction material layer 12 .

Embodiment 4

As shown in FIGS. 8 and 9 , an electronically controlled fiber grating system includes the fiber grating element 1 described in the third embodiment and a magnetic field generating device 2 , and the magnetic field generating device 2 is used to generate the electromagnetic induction material layer 12 The alternating magnetic field acting on each other causes the electromagnetic induction material layer 12 to heat up and then heat the normal grating modulation region of the optical fiber 11 to change the refractive index of the normal grating modulation region to form a fiber grating.

The electronically controlled fiber grating system further includes an input connector and an output connector, the input connector is provided at one end of the fiber grating element 1, and the output connector is provided at the other end of the fiber grating element 1, or the input connector The connector and the output connector are arranged at the same end of the fiber grating element 1 .

The magnetic field generating device 2 includes a magnetic field transmitter 21 and a power control module 22. The power control module 22 is electrically connected to the magnetic field transmitter 21 to output alternating current to the magnetic field transmitter 21, thereby enabling all The magnetic field transmitter 21 generates the alternating magnetic field.

In this embodiment, the magnetic field transmitter 21 includes an electromagnetic coil, which surrounds the fiber grating element 1 in the axial direction.

The input connector is used to connect the light source generating device 3, so that the light source generating device 3 couples the detection beam into the fiber grating element 1; the output connector is used to connect the spectrum detection device 4, so that the spectrum The detection device 4 receives the light beam transmitted or reflected from the fiber grating element 1, and obtains the real-time writing spectrum of the fiber grating.

When the input connector and the output connector are arranged at the same end of the fiber grating element 1 , the electronically controlled fiber grating system further includes a coupling device 5 , and the input connector and the output connector are connected to the At the same end of the fiber grating element 1 , the coupling device 5 can couple the incident detection beam into the fiber grating element 1 , and couple the reflected beam into the spectrum detection device 4 .

Embodiment 5

As shown in Figures 8 and 9, an electronically controlled fiber grating preparation system is not limited to be applied to the preparation method described in the first embodiment, including the electronically controlled fiber grating system described in the fourth embodiment, and

a light source generating device 3 for coupling a detection beam into the fiber grating element 1;

The spectrum detection device 4 is used for receiving the light beam transmitted or reflected from the fiber grating element 1 to obtain the real-time writing spectrum of the fiber grating.

The light source generating device 3 is connected to the input connector of the electronically controlled fiber Bragg grating system, and the spectrum detection device 4 is connected to the output connector of the electronically controlled fiber Bragg grating system.

In a specific implementation, as shown in FIG. 8 , the light source generating device 3 is connected to one end of the fiber grating element 1, the spectrum detection device 4 is connected to the other end of the fiber grating element 1, and the During the transmission process of the detection beam in the fiber grating element 1, when passing through the normal position grating modulation area, part of the detection beam will continue to transmit forward through the fiber grating, and the spectrum detection device 4 transmits it through receiving of the beam, the transmission spectrum is obtained as the real-time writing spectrum of the fiber grating.

In another specific implementation, as shown in FIG. 9 , the light source generating device 3 and the spectrum detecting device 4 are connected to the same end of the fiber grating element 1 , and the detection beam is in the fiber grating element 1 . During the transmission process, when passing through the normal grating modulation area, part of the detection beam will be reflected by the fiber grating and return to the original path. Write spectra in real time.

At this time, preferably, the light source generating device 3 and the spectrum detecting device 4 are connected to the same end of the fiber grating element 1 through a coupling device 5, and the coupling device 5 can couple the incident detection beam to the fiber grating. In the element 1 , the reflected light beam is coupled into the spectral detection device 4 .

When modulating the real-time writing spectrum of the light grating, the technician can manually control the power supply control module 22 in the magnetic field generating device 2 according to the real-time writing spectrum obtained by the spectrum detection device 4 to control the power supply The alternating current output by the control module 22 further controls the alternating magnetic field generated by the magnetic field transmitter 21, and finally modulates the real-time writing spectrum of the fiber grating into a desired writing spectrum.

Of course, the preparation system can also include a processing control host (not shown in the figure), the processing control host is communicatively connected between the spectrum detection device 4 and the magnetic field generating device 2, and is used for according to the spectrum detection device. 4. The obtained real-time writing spectrum automatically controls the power control module 22 of the magnetic field generating device 2 to automatically modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum.

The above-mentioned embodiment only expresses the embodiment of the present invention, and its description is more specific and detailed, but it should not be construed as a limitation to the patent scope of the present invention, but any technical solution obtained in the form of equivalent replacement or equivalent transformation , should fall within the protection scope of the present invention.

Claims (10)

1. a preparation method of electronically controlled fiber grating, is characterized in that, comprises the steps: Step S1: pre-processing the optical fiber, so as to fabricate and cover an electromagnetic induction material layer on the normal position grating modulation area distributed along the axial direction of the optical fiber to form a fiber grating element; Step S2: using an alternating magnetic field to interact with the electromagnetic induction material layer to heat the electromagnetic induction material layer and then heat the normal grating modulation region of the optical fiber to change the refraction of the normal grating modulation region rate to form a fiber grating. 2. The method for preparing an electronically controlled fiber grating according to claim 1, characterized in that, after step S2, the method further comprises the following steps: Step S3: modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum by controlling the alternating magnetic field. 3. The preparation method of electronically controlled fiber grating according to claim 2, wherein step S3 comprises the following steps: Step S3.1: coupling the detection beam into the fiber grating element; Step S3.2: receiving the light beam transmitted or reflected from the fiber grating element to obtain the real-time writing spectrum of the fiber grating; Step S3.3: Control the alternating magnetic field to modulate the real-time writing spectrum of the fiber grating into a desired writing spectrum. 4. The method for preparing an electronically controlled fiber grating according to claim 2 or 3, wherein the resonant peak wavelength of the fiber grating is modulated by controlling the magnetic field strength and/or the alternating frequency of the alternating magnetic field , the loss peak intensity and the preparation modulation time are at least the same. 5 . The method for preparing an electronically controlled fiber grating according to claim 2 or 3 , wherein the alternating magnetic field is controlled by controlling an alternating current that generates the alternating magnetic field. 6 . 6. The preparation method of electronically controlled fiber grating according to claim 5, characterized in that, by controlling the current and voltage intensity and/or the alternating frequency of the alternating current, the resonance peak wavelength, The loss peak intensity is at least the same as in the preparation modulation time. 7. The preparation method of electronically controlled fiber grating according to claim 1, wherein step S1 comprises the following steps: Step S1.1: According to the phase matching formula, determine the position of the normal position grating modulation region of the required fiber grating along the axial direction of the fiber; Step S1.2: fabricating a layer covering the electromagnetic induction material on the normal grating modulation area distributed along the axial direction of the optical fiber. 8. The method for preparing an electronically controlled fiber grating according to claim 7, wherein step S1.2 comprises the following steps: Step S1.2.1: fabricating and covering an insulating and heat insulating material layer on the surface of the optical fiber; Step S1.2.2: peel off the insulating and heat-insulating material layer covering the normal-position grating modulation area, so that the normal-position grating modulation area is exposed from the insulating and heat-insulating material layer; Step S1.2.3: forming a layer covering the electromagnetic induction material on the exposed normal-position grating modulation area. 9. The preparation method of electronically controlled fiber grating according to claim 7, wherein step S1.2 comprises the following steps: Step S1.2.1: making a coating material layer on the surface of the optical fiber; Step S1.2.2: peel off the coating material layer covering the normal-position grating modulation area, so that the normal-position grating modulation area is exposed from the coating material layer; Step S1.2.3: forming a layer covering the electromagnetic induction material on the exposed normal-position grating modulation area; Step S1.2.4: peel off the remaining coating material layer. 10. The method for preparing an electronically controlled fiber grating according to claim 7, wherein step S1.2 comprises the following steps: Step S1.2.1: making a layer covering the electromagnetic induction material on the surface of the optical fiber; Step S1.2.2: fabricating and covering a photosensitive material layer on the surface of the electromagnetic induction material layer; Step S1.2.3: exposing and developing the photosensitive material layer, so that the electromagnetic induction material layer covering the outside of the normal grating modulation area is exposed from the photosensitive material layer; Step S1.2.4: Etch the exposed electromagnetic induction material layer.

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