CN214252649U - Device for writing arbitrary dispersion optical fiber grating - Google Patents

Abstract

The utility model discloses a device of arbitrary dispersion fiber grating of inscribing, including light source module, phase place mask slice, fiber holder, ASE light source and spectrum appearance, its characterized in that still includes: the control module is used for selecting parameters of the grating to be inscribed according to requirements and generating electric pulse signals distributed in an apodization mode according to the parameters; and the intensity control module comprises a programmable spatial light modulator and a function generator, and the function generator drives the programmable spatial light modulator to adjust the laser intensity of the laser output by the intensity control module according to the electric pulse signal. The utility model discloses can freely adjust the dispersion value of the fiber grating who produces, reduce the dependence to phase place mask slice.

Description

Device for writing arbitrary dispersion optical fiber grating

Technical Field

The utility model relates to a fiber grating technical field, more specifically the theory relates to a device of carving arbitrary chromatic dispersion fiber grating.

Background

In recent years, with the development of an optical-solid hybrid ultrafast laser, fiber gratings are widely applied to the application fields of fiber laser cavity mirrors, ultrafast laser stretchers and the like. In the fields of ultrafast laser stretcher, ultrafast laser seed source and the like, more and more fiber gratings with specified dispersion values are required, but from the current situation, the main writing method of the fiber gratings is as follows: the method comprises three methods, namely a phase mask method, an interference method, a direct writing method and the like, wherein only the phase mask method is suitable for manufacturing the fiber grating with a specific dispersion value.

In the prior art, the disclosure number is CN102621609B, which is named as a random apodizing fiber grating writing device and a writing method, and the basic principle is that ultraviolet laser passes through a phase mask plate, and the phase mask plate is diffracted, wherein 0-order diffraction is inhibited (less than or equal to 3%), and ± 1-order diffraction (more than or equal to 33%) generates interference, and the interference is applied to an optical fiber to form a fiber grating.

However, the dispersion value of the fiber grating produced in the prior art directly depends on the chirp rate of the selected phase mask plate, and cannot be freely adjusted, and if the fiber grating with other dispersion values of the wavelength is to be written, a new phase mask plate needs to be purchased, which causes a lot of expenses.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: the utility model aims to provide a device for inscribing arbitrary dispersion fiber grating to the not enough of prior art, can freely adjust the dispersion value of the fiber grating who produces, reduce the dependence to phase mask plate.

The technical scheme is as follows: a device for inscribing any dispersion fiber grating, including light source module, phase place mask slice, fiber holder utensil, ASE light source and spectrum appearance, its characterized in that still includes:

the control module is used for selecting parameters of the grating to be inscribed according to requirements and generating electric pulse signals distributed in an apodization mode according to the parameters;

and the intensity control module comprises a programmable spatial light modulator and a function generator, and the function generator drives the programmable spatial light modulator to adjust the laser intensity of the laser output by the intensity control module according to the electric pulse signal.

Furthermore, the light source module comprises a laser light source and a beam shaping module for outputting a light beam to the laser light source, wherein the beam shaping module comprises a beam expanding lens, a two-dimensional diaphragm and a homogenizing lens.

Further, the light source module further comprises a reflector, and the reflector is mounted on the planar mounting plate and used for guiding the light beam output by the light beam shaping module to the intensity control module.

Further, the method also comprises the following steps:

the phase mask plate adjusting module comprises a high-precision microscopic monitoring module and a front and rear electric displacement table, wherein the high-precision microscopic monitoring module is used for acquiring the horizontal distance between the phase mask plate and the grating to be engraved, and the phase mask plate and the high-precision microscopic monitoring module are connected to the front and rear electric displacement tables.

Furthermore, the high-precision microscopic monitoring module comprises a metal cage, and a microscope objective and a microscope eyepiece which are arranged in the metal cage from top to bottom, wherein a CCD image sensor is arranged below the metal cage.

Furthermore, the distance between the phase mask plate and the grating to be inscribed is 20-30 μm.

Has the advantages that:

(1) the utility model discloses an intensity of setting up adjustment laser of intensity modulation module, make the photoinduced refracting index of optic fibre change and produce as required to realize the inscription of the fiber grating of arbitrary dispersion value, the phase place mask plate that the utility model uses can be the even phase place mask plate that the cycle coincide, and 1 even phase place mask plate of configuration in same wave band just can realize the inscription of the fiber grating of the arbitrary dispersion value of this wave band like this, great reduction in production cost;

(2) the utility model discloses utilize the microscopic monitoring module of high accuracy, the experiment has confirmed that the distance between phase place mask slice and the optic fibre should be 20-30um, on the basis of avoiding fibre core and fibre core reverberation to damage the mask slice, realized the optimization of coherence (through surveying actual value and exceeding 90%, 50-60% before the contrast, there is promotion by a relatively large margin), this great reduction work laser to the damage of optic fibre core, the effectual spontaneous heating that reduces the fiber grating during operation to promote fiber grating's tolerance power (be applied to the laser direction) and reduced insertion loss (be applied to communication sensing direction);

(3) the utility model discloses intensity modulation module based on design of spatial light modulator able to programme can use as arbitrary apodization module as required, realizes arbitrary apodization effect to reduce equipment cost.

Drawings

FIG. 1 is a schematic diagram of an intensity control module and a focusing module according to embodiment 1;

FIG. 2 is a schematic diagram of an embodiment 1 for embodying a beam shaping module;

FIG. 3 is a schematic diagram of an intensity control module according to embodiment 1;

FIG. 4 is a schematic view of embodiment 1 for embodying a focusing module;

FIG. 5 is a schematic view of a high-precision microscopic monitoring module according to example 1;

fig. 6 is a schematic diagram of embodiment 2 for embodying a high-precision microscopic monitoring module.

In the figure, 11, a left and right electric displacement table; 12. a planar mounting plate; 21. an ASE light source; 22. a spectrometer; 23. an optical fiber clamp; 24. a U-shaped workpiece; 31. a beam expander; 32. a two-dimensional diaphragm; 33. a homogenizing mirror; 34. a mirror; 35. a laser light source; 4. a focusing module; 41. a focusing mirror; 42. a front and rear electric displacement table; 5. a high-precision microscopic monitoring module; 51. a horizontal electric displacement table; 52. a metal cage; 53. a microscope objective; 54. a microscope eyepiece; 55. a CCD image sensor; 6. a grating is to be written; 7. a strength control module; 71. a function generator; 72. a programmable spatial light modulator; 8. a control module; 9. and a phase mask plate.

Detailed Description

The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the embodiments.

Example 1: a device for writing an arbitrary dispersion fiber grating, as shown in fig. 1-5, includes a light source module, a phase mask 9, a fiber clamp 23, an ASE light source 21, a spectrometer 22, a control module 8, an intensity control module 7, a focusing module 4, and a moving module.

The light source module comprises a laser light source 35 and a beam shaping module for outputting light beams to the laser light source 35, wherein the beam shaping module comprises a beam expanding lens 31, a two-dimensional diaphragm 32 and a homogenizing lens 33.

The laser light source 35 may be a 248nm excimer laser, but is not limited thereto, and the laser light source 35 is used for outputting working laser and is connected to the control module 8 through a signal line, that is, the control module 8 may output laser by controlling the laser light source 35.

The beam shaping module is used for shaping the beam output by the laser source 35 to make the beam more uniform. The two-dimensional diaphragm 32 is used for filtering out uneven parts on the periphery of the light beam, and the homogenizing mirror 33 is used for homogenizing the light beam into a uniform circular light beam, in practical application, if the point light source 21ASE is used, the homogenizing mirror 33 can be removed, and if the surface light source 21ASE is used, the beam expanding mirror 31 can be removed.

In order to direct the beam output by the beam shaping module to the intensity control module 7 for adjustment, a mirror 34 may also be provided, the mirror 34 being mounted on the planar mounting plate 12. As shown in fig. 1, the mirror 34 directs the beam output by the beam shaping module to the intensity control module 7 with a 90 ° deflection.

The intensity control module 7 is used for adjusting the laser intensity of the laser output by the intensity control module 7, and comprises a programmable spatial light modulator 72 and a function generator 71, wherein the function generator 71 drives the programmable spatial light modulator 72 to adjust the laser intensity of the laser output by the light source module according to the electric pulse signal.

It will be appreciated that the programmable spatial light modulator 72, whose drive circuit is controlled by the electrical pulse signal generated by the function generator 71, comprises a plurality of individual pixels spatially arranged in a one-dimensional or two-dimensional array, each pixel being independently controlled by an electrical signal and varying its own optical intensity transmittance to achieve spatial intensity modulation of the exposure beam, and that the programmable spatial light modulator 72 is made of a suitable crystal or polymer material depending on the wavelength band of the laser light.

The function generator 71 can be connected to the control module 8 through a GPIB interface, and generates a desired voltage signal by using its own waveform editing software, and the voltage signal controls the driving circuit of the programmable spatial light modulator 72 to realize the programmable operation of the programmable spatial light modulator, thereby adjusting the laser intensity of the laser output by the programmable spatial light modulator.

In some embodiments, the energy of the laser light impinging on the grating 6 to be written is adjusted as follows:

the focusing module 4 is located below the intensity control module 7 and includes a front and rear electric displacement stage 42 and a focusing mirror 41 installed on the front and rear electric displacement stage 42, and the front and rear electric displacement stage 42 is configured to adjust a focal position of the laser irradiated on the grating 6 to be inscribed according to the energy adjustment signal, so as to change energy of the laser irradiated on the grating 6 to be inscribed.

The control module 8 obtains an energy adjustment signal according to the feedback information of the spectrometer 22 to control the front and rear electric displacement stages 42 to move back and forth, so as to drive the focusing lens 41 connected with the front and rear electric displacement stages 42 to move, and further adjust the focal position of the laser irradiated on the grating 6 to be inscribed, so as to change the energy of the laser irradiated on the grating 6 to be inscribed.

It can be understood that the phase mask 9 is located below the focusing module 4, and is used for dividing the laser output by the focusing module 4 into two laser beams, so as to generate interference on the grating 6 to be written.

In practical application, a U-shaped workpiece 24 may be provided, two mounting tables are provided at two ends of the U-shaped workpiece 24, and the optical fiber clamp 23 is connected to the mounting tables to connect the optical fiber to be manufactured to the optical fiber clamp 23 for fixing. The ASE light source 21 and the spectrometer 22 are respectively positioned at two sides of the optical fiber clamp 23, the ASE light source 21 and the spectrometer 22 are respectively connected with two ends of the grating 6 to be written, wherein the spectrometer 22 is used for monitoring a grating transmission spectrum and a grating reflection spectrum in the grating manufacturing process and forming feedback information.

The optical fiber clamp 23 is installed at two ends of the U-shaped workpiece 24, the grating 6 to be written, which is subjected to hydrogen loading and coating stripping, is fixed on the optical fiber clamp 23, one end of the grating 6 to be written is connected with the ASE light source 21, the other end of the grating is connected with the spectrometer 22, the spectrometer 22 is connected to the control module 8, and the control module 8 is used for receiving feedback information of the spectrometer 22.

In order to realize the manufacture of the whole grating to be manufactured, the moving module comprises a left electric displacement table 11 and a right electric displacement table 11, the strength control module 7, the phase mask plate 9 and the focusing module 4 are all installed on the left electric displacement table 11 and the right electric displacement table 11 through a plane installation plate 12, the left electric displacement table 11 and the right electric displacement table 11 are connected with a control module 8, the control module 8 controls the left electric displacement table 11 and the right electric displacement table 11 to move left and right synchronously according to the feedback information of the spectrometer 22, the writing of the whole fiber grating is realized, and when the spectrum information of the fiber grating returned by the spectrometer 22 meets the set requirement, the writing of the fiber grating is completed.

In practical application, the laser light source 35 and the beam shaping module in the light source module are not arranged on the left and right electric displacement tables 11 and do not move left and right along with the left and right electric displacement tables 11.

The specific implementation process is as follows:

installing an optical fiber clamp 23 at two ends of a U-shaped workpiece 24, fixing the grating 6 to be inscribed which is completely carried with hydrogen and stripped with a coating layer on the optical fiber clamp 23, connecting one end of the grating 6 to be inscribed with an ASE light source 21, connecting the other end of the grating to be inscribed with a spectrometer 22, and connecting the spectrometer 22 with a control module 8;

controlling a horizontal electric displacement table 51 according to a control module 8 to adjust the distance between a phase mask plate 9 and the grating 6 to be engraved to 20-30 μm;

controlling the laser light source 35 to output laser according to the control module 8, filtering and homogenizing the output laser by the beam shaping module, and then striking the laser on the function generator 71 of the intensity control module 7 through the reflector 34;

the control module 8 selects parameters of the grating 6 to be inscribed according to requirements, generates an electric pulse signal with apodization distribution according to the parameters, and the function generator 71 drives the programmable spatial light modulator 72 to adjust the laser intensity of output laser according to the electric pulse signal;

the laser output from the intensity control module 7 is irradiated on the focusing module 4, the control module 8 obtains an energy adjusting signal according to the feedback information of the spectrometer 22, and controls the front and rear electric displacement table 42 to move the focus of the focusing mirror 41 back and forth, so as to change the energy irradiated on the grating 6 to be inscribed;

laser output by the focusing module 4 is irradiated onto a phase mask plate 9, the phase mask plate 9 divides a point light beam into two laser beams, interference is generated on a fiber core of a grating 6 to be engraved, and meanwhile, the control module 8 controls the left and right electric displacement tables 11 to synchronously move left and right according to feedback information of the spectrometer 22, so that writing of the fiber grating is realized;

when the spectrum information of the fiber grating returned by the spectrometer 22 meets the set requirements, the fiber grating writing is completed.

Example 2: a device for writing an arbitrary dispersion fiber grating, which is different from embodiment 1, as shown in fig. 6, further includes a phase mask adjusting module, the phase mask adjusting module includes a high-precision microscopic monitoring module 5 for acquiring a horizontal distance between a phase mask 9 and a grating 6 to be written, and a horizontal electric displacement table 51, the phase mask 9 and the high-precision microscopic monitoring module 5 are connected to the horizontal electric displacement table 51, and the horizontal electric displacement table 51 is connected to a planar mounting plate 12.

The high-precision microscopic monitoring module 5 comprises a metal cage 52, a microscope objective 53 and a microscope eyepiece 54 which are arranged in the metal cage 52 from top to bottom, and a CCD image sensor 55 is arranged below the metal cage 52.

It can be understood that the high-precision microscopic monitoring module 5 can send the detected distance information to the control module 8, and the control module 8 controls the horizontal electric displacement table 51 to adjust the height of the phase mask 9, so as to adjust the distance between the phase mask 9 and the grating 6 to be written.

In practical application, the distance between the phase mask plate 9 and the grating 6 to be written can be adjusted to 20-30 μm. By utilizing the high-precision microscopic monitoring module 5, experiments confirm that the distance between the phase mask plate 9 and the optical fiber should be 20-30um, and on the basis of avoiding the damage of the mask plate by fiber core and fiber core reflected light, the optimization of the coherence degree is realized (the measured actual value exceeds 90%, and is 50-60% before comparison, and is greatly improved), so that the damage of working laser to the fiber core of the optical fiber is greatly reduced, the spontaneous heating of the optical fiber grating during working is effectively reduced, and the tolerance power (applied to the laser direction) of the optical fiber grating is improved, and the insertion loss (applied to the communication sensing direction) is reduced.

As mentioned above, although the present invention has been shown and described with reference to certain preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (4)

1. The utility model provides a device of carving arbitrary dispersion fiber grating, includes light source module, phase mask board (9), fiber holder (23), ASE light source (21) and spectrometer (22), its characterized in that still includes:

the control module (8) is used for selecting parameters of the grating (6) to be inscribed according to requirements and generating electric pulse signals distributed in an apodization mode according to the parameters;

the intensity control module (7) comprises a programmable spatial light modulator (72) and a function generator (71), wherein the function generator (71) drives the programmable spatial light modulator (72) according to the electric pulse signal to adjust the laser intensity of the laser output by the intensity control module (7);

the light source module comprises a laser light source (35) and a beam shaping module used for outputting a light beam to the laser light source (35), and the beam shaping module comprises a beam expanding lens (31), a two-dimensional diaphragm (32) and a homogenizing lens (33);

the light source module further comprises a reflector (34), wherein the reflector (34) is arranged on the plane mounting plate (12) and is used for guiding the light beam output by the light beam shaping module to the intensity control module (7).

2. The apparatus of claim 1, further comprising:

the phase mask adjusting module comprises a high-precision microscopic monitoring module (5) for acquiring the horizontal distance between the phase mask (9) and the grating (6) to be inscribed, and a horizontal electric displacement table (51), wherein the phase mask (9) and the high-precision microscopic monitoring module (5) are connected to the horizontal electric displacement table (51).

3. The device according to claim 2, characterized in that the high-precision microscopic monitoring module (5) comprises a metal cage (52), and a microscope objective (53) and a microscope eyepiece (54) arranged in the metal cage (52) from top to bottom, wherein a CCD image sensor (55) is arranged below the metal cage (52).

4. Device according to claim 2, characterized in that the distance between the phase mask (9) and the grating (6) to be written is 20-30 μm.

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