CN112894128B - High-temperature-resistant II-type optical waveguide processing method and system and high-temperature-resistant II-type double-line waveguide - Google Patents

Abstract

The application provides a high temperature resistant type II optical waveguide processing method, system and high temperature resistant type II dual-wire waveguide, and relates to the technical field of waveguide preparation. It can solve the problem of how to quickly obtain a high temperature resistant type II bifilar waveguide. The method includes: obtaining a Gaussian beam; using a spatial light modulator to perform focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field with a double focus light intensity distribution along the laser propagation direction; The processed samples were scanned in situ for many times to obtain a type II bifilar waveguide with high temperature resistance and low loss.

Description

High temperature resistant type II optical waveguide processing method, system and high temperature resistant type II dual-wire waveguide

technical field

The present application relates to the technical field of optical waveguide preparation, in particular to a high temperature resistant type II optical waveguide processing method, system and high temperature resistant type II bifilar waveguide.

Background technique

The waveguide is the basic unit of the integrated chip. For extreme fields such as aerospace, the device is often required to withstand high temperatures. However, the optical waveguides often used by researchers for direct writing of glass and polymer materials have limited operating temperatures. High-performance optical waveguides and integrated photonic devices are very necessary in extreme fields such as aerospace. Type I waveguide is easy to be erased at high temperature and difficult to retain, so the related field adopts type II bifilar waveguide induced by stress.

The waveguide prepared by femtosecond laser direct writing has the advantages of high flexibility and true three-dimensionality, and the prepared optical waveguide has low transmission loss. However, the traditional femtosecond laser direct writing technology for making type II waveguides is to process the sample twice by laser, and obtain two damage marks on the sample respectively, so as to obtain a complete type II dual-wire waveguide. Scanning the sample in two steps is complicated and time-consuming.

It can be seen that how to quickly obtain a type II bifilar waveguide with high temperature resistance and low loss is an urgent problem to be solved in related fields.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a high temperature resistant type II optical waveguide processing method, system and high temperature resistant type II bifilar waveguide, which can solve the problem of how to quickly prepare a high temperature resistant and low loss type II bifilar waveguide.

A first aspect of the embodiments of the present application provides a high temperature resistant type II optical waveguide processing method, the method comprising:

get a Gaussian beam;

Using a spatial light modulator to shape the focal field of the Gaussian beam to obtain a three-dimensional focal field with a bifocal light intensity distribution along the laser propagation direction;

The sample to be processed is scanned multiple times by the laser beam after focal field shaping, and the high temperature resistant type II double-wire waveguide is obtained.

Optionally, the method further includes:

Determine the focal field information required for processing the waveguide according to the double-line spacing of the waveguide required by the user;

The focal field information is calculated by using the analytical bifocal phase formula, and a phase distribution showing bifocals on a lateral plane is obtained; wherein, the lateral plane is a plane perpendicular to the laser propagation direction;

According to the phase distribution, a bifocal phase plate is obtained;

loading the bifocal phase plate onto the spatial light modulator;

The focal field shaping of the Gaussian beam is carried out by using a spatial light modulator, and a three-dimensional focal field with a bifocal intensity distribution along the laser propagation direction is obtained, including:

Using the spatial light modulator loaded with the bifocal phase plate to perform focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field with bifocal light intensity distribution along the laser propagation direction;

Or, use the analytical multi-focus phase formula to calculate the focal field information to obtain a multi-focus phase plate, load the multi-focus phase plate into the spatial light modulator, perform focal field shaping on the Gaussian beam, and obtain the propagation along the laser beam. The vertical direction presents a discrete annular three-dimensional optical focal field composed of multiple focal points and inclined along the vertical direction.

Optionally, using the focal field shaped laser beam to perform multiple in-situ scanning processing on the sample to be processed, to obtain a type II bifilar waveguide with high temperature resistance and low loss, including:

Using the focal-field shaped laser beam whose bifocal light intensity distribution conforms to the phase information, the sample to be processed is subjected to multiple in-situ scanning processing to obtain the high-temperature-resistant and low-loss laser beam with double-line spacing conforming to the phase information. Type II bifilar waveguide; the multiple in-situ scanning processing is used to accumulate and enhance the stress field around the damage trace of the type II bifilar waveguide, so that the type II bifilar waveguide can counteract the effects of high temperature annealing. After the stress erasing, the confinement effect on light reaches a preset requirement; wherein, the preset requirement means that the transmission loss of the waveguide before and after high temperature annealing changes within 20%.

Optionally, the method further includes:

Taking each parameter of the parameters affecting the waveguide performance as an invariant in turn; wherein, the parameters affecting the waveguide performance include: pulse energy, scanning speed, double line spacing, waveguide line length, and the number of repeated scans;

respectively changing the values of the parameters affecting the waveguide performance to obtain multiple sets of parameter combinations;

Taking each group of parameter combinations as processing parameters in turn, the reference sample is scanned by the laser beam after focal field shaping, and multiple reference waveguides are obtained;

The optimal combination of processing parameters is determined according to the characterization analysis results of the plurality of reference waveguides.

Optionally, the optimal processing parameters are: the pulse energy is 1.16 μJ, the scanning speed is 3 mm/s, the double line spacing is 20 μm, the longitudinal line length of the waveguide is 16 μm, and the in-situ scanning is repeated three times.

A second aspect of the embodiments of the present application provides a high temperature resistant type II optical waveguide processing system, the system includes: a processing device, and the processing device includes: a femtosecond laser, a spatial light modulator, and a three-dimensional displacement platform;

the femtosecond laser is used to generate a Gaussian beam;

The spatial light modulator is used for shaping the focal field of the Gaussian beam to obtain a three-dimensional focal field with a bifocal light intensity distribution along the laser propagation direction;

The three-dimensional displacement platform is controlled by a computer and is used to move the sample to be processed, and to process the sample to be processed by the method described in the first aspect of the present application, so as to obtain a type II bifilar waveguide.

Optionally, the processing device further includes: a CCD camera;

The CCD camera is used to observe the processing situation of the sample to be processed in real time; the processing situation refers to whether the laser beam after focal field shaping is focused on the sample to be processed to form a focus.

A third aspect of the embodiments of the present application provides a type II bifilar waveguide with high temperature resistance and low loss, which is prepared by using the method described in the first aspect of the present application.

The embodiment of the present application uses a spatial light modulator to shape the original ellipsoid light intensity distribution after the Gaussian beam is focused into a three-dimensional optical focal field with a bifocal light intensity distribution along the laser propagation direction, and the laser beam after shaping by the focal field is shaped The sample to be processed is scanned to obtain a type II bifilar waveguide in a single scan. Compared with the traditional method in which the type II bifilar waveguide can be obtained by scanning two damage traces of the type II bifilar waveguide in sequence, the optical waveguide processing method proposed in the embodiment of the present application is faster. Further, in the present application, by loading the phase information into the spatial light modulator, a bifocal laser beam that can be shaped to conform to a specific focal field distribution can be obtained, and as long as the phase information is adjusted, a bifocal three-dimensional focal field with different intervals can be shaped, Thus, type II bifilar waveguides with different bifilar spacings are prepared.

In the embodiment of the present application, the laser beam after focal field shaping is used to perform multiple in-situ scanning processing on the sample to be processed, so as to accumulate and enhance the stress field around the damage trace of the type II bifilar waveguide, so as to offset the damage caused by high temperature annealing. After stress erasing, the waveguide can still confine light well with low transmission loss. A type II bifilar waveguide with high temperature resistance and low loss is obtained.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application. , for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

1 is a flow chart of the steps of the high temperature resistant type II optical waveguide processing method in the embodiment of the present application;

2 is a schematic diagram of a bifocal phase plate obtained by an example of the present application;

3 is a simulated light intensity distribution diagram on the yz plane of a bifocal three-dimensional focal field obtained by adopting an example of the present application using the focal field shaping method proposed in the embodiment of the present application;

Fig. 4 is a micrograph of the cross-sectional morphology of the type II bifilar waveguide A before high temperature annealing;

Figure 5 is a micrograph of the cross-sectional morphology of the type II bifilar waveguide A after high temperature annealing;

Fig. 6 is the distribution diagram of optical fiber guided mode under V polarization;

Fig. 7 is the mode field distribution diagram of type II bifilar waveguide A in the input fiber guided mode under V polarization before high temperature annealing;

Fig. 8 is the mode field distribution diagram of the type II bifilar waveguide A in the input fiber guided mode under V polarization after high temperature annealing;

9 is a schematic diagram of a processing device of an optical waveguide processing system according to an embodiment of the present application;

FIG. 10 is a schematic diagram of an apparatus for testing the performance of an optical waveguide according to an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

FIG. 1 is a flow chart of the steps of the high temperature resistant type II optical waveguide processing method in the embodiment of the present application. As shown in FIG. 1 , the steps of preparing the high temperature resistant type II optical waveguide in the embodiment of the present application are as follows:

The high temperature resistant type II optical waveguide prepared in the present application has the characteristics of high temperature resistance and low loss.

Step S11: Obtain a Gaussian beam.

The output laser beams of femtosecond lasers are generally Gaussian beams.

In an example of this application, a femtosecond laser with an output center wavelength of 1030 nm is used to generate a Gaussian beam, and a half-wave plate and a Glan-Taylor polarizing prism are used to modulate the output optical power of the Gaussian beam. The Gaussian beam is expanded and incident on the spatial light modulator.

Step S12 : using a spatial light modulator to perform focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field with bifocal light intensity distribution along the laser propagation direction.

The focal field shaping of the Gaussian beam means that the original ellipsoid light intensity distribution after the Gaussian beam is focused is shaped into a three-dimensional optical focal field with a bifocal light intensity distribution along the laser propagation direction. The shaped laser beam is focused into the sample to be processed by the objective lens, and the sample to be processed is moved through the three-dimensional displacement platform, and two damage traces can be obtained at the same time.

Another embodiment of the present application proposes a specific implementation method for focal field shaping of a Gaussian beam.

Step S12-1: Determine the focal field information required for processing the waveguide according to the dual-line spacing of the waveguide required by the user.

In an example of the present application, according to the waveguide performance required by the user, the determined focal field information is the biline spacing of the finally obtained high temperature resistant type II bifilar waveguide.

Step S12-2: Calculate the focal field information by using the analytical bifocal phase formula to obtain a bifocal phase distribution on a lateral plane; wherein, the lateral plane is a plane perpendicular to the laser propagation direction.

The bifocal phase formula is divided into terms that control the movement of the focus in the XY plane, and terms that control the movement of the focus in the Z direction.

Phase distribution refers to the phase information carried by the laser beam after focal field shaping.

The transverse plane is the plane perpendicular to the propagation direction of the femtosecond laser beam.

In an example of the present application, the term of the bifocal phase formula to control the movement of the focus in the XY plane is shown in formula (1):

Among them, x ₀ and y ₀ are the coordinates of each point on the entrance pupil surface of the focusing objective, Δx is the offset of the focal field from the center of the focal field in the x direction after focusing by the objective lens, and Δy is the focal distance from the center of the focal field after focusing by the objective lens in y Offset of direction, NA is the numerical aperture of the focusing objective, λ ₀ is the center wavelength of the laser beam in vacuum, R is the entrance pupil radius of the focusing objective; n _t is the refractive index of the sample to be processed.

The term that controls the movement of the focus in the Z direction is shown in equation (2):

Among them, Δz is the deviation of the focal point from the center of the focal field in the z direction after being focused by the objective lens.

Equations (1) and (2) can be extended to the multi-focus phase formula, and the Gaussian beam is shaped into a discrete annular three-dimensional optical focal field formed by multiple focal points and inclined in the vertical direction along the laser propagation direction. Sub-scans to fabricate recessed clad waveguides.

Step S12-3: Obtain a bifocal phase plate or a multifocal phase plate according to the phase distribution.

FIG. 2 is a schematic diagram of a bifocal phase plate obtained by an example of the present application. The phase plate shown in FIG. 2 can generate a bifocal light intensity distribution with an interval of 15 μm. Adjusting the phase information of the interval between the bifocals can also obtain the phase distribution that presents the bifocals with an interval of 20 μm and 26 μm. The phase information carried by the multifocal phase plate is different from that of the bifocal phase plate. Specifically, the focus field information of the multifocal phase formula obtained by the expansion of equations (1) and (2) can be calculated to obtain a multifocal phase distribution.

Step S12-4: Load the bifocal phase plate on the spatial light modulator; or, load the multi-focus phase plate on the spatial light modulator.

The spatial light modulator is connected to the computer, and the phase plate with bifocal phase distribution is input into the computer, so as to complete the purpose of loading the bifocal phase plate on the spatial light modulator.

Step S12-5: using the spatial light modulator loaded with the bifocal phase plate to perform focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field with bifocal light intensity distribution along the laser propagation direction; Or, use the spatial light modulator loaded with the multi-focus phase plate to perform focal field shaping on the Gaussian beam to obtain a discrete ring formed by multiple focal points and inclined in the vertical direction along the laser propagation direction. three-dimensional focal field.

FIG. 3 is a simulated light intensity distribution diagram on the yz plane of a three-dimensional focal field with a bifocal light intensity distribution after focal field shaping proposed by an embodiment of the present application using an example of the present application. In this embodiment, the phase information loaded by the spatial light modulator is the phase plate shown in FIG. 2 , and FIG. 3 verifies that by using the focal field shaping method proposed in the embodiment of the present application, it is possible to obtain the light intensity distribution corresponding to the set phase information. 3D focal field. The horizontal coordinate of FIG. 3 is the coordinate of the spatial distribution of the focal field in the y direction, and the vertical coordinate is the coordinate of the spatial distribution of the focal field in the z direction.

Step S13 : using the laser beam shaped by the focal field to scan the sample to be processed multiple times in situ to obtain a type II bifilar waveguide with high temperature resistance and low loss.

By using the method for processing the waveguide according to the embodiment of the present application, the sample to be processed can be scanned in-situ for many times by using the laser beam with a bifocal light intensity distribution after focal field shaping, and a high temperature resistant and low loss II with two damage marks can be obtained at the same time. type two-wire waveguide. Multiple in-situ scanning processing can cumulatively enhance the stress field around the damage trace of the type II bifilar waveguide, so that the type II bifilar waveguide can restrain the light after the stress erasing caused by high temperature annealing is offset. meet the preset requirements. The preset requirement means that the transmission loss of the waveguide before and after high temperature annealing changes within 20%.

In an example of the present application, pure sapphire with a relatively large refractive index (about 1.77) is used as the sample to be processed, and the pure sapphire has the characteristics of high temperature resistance.

In another embodiment of the present application, a type II bifilar waveguide with high temperature resistance and low loss is prepared.

The sample to be processed is scanned and processed for multiple times by a laser beam whose focal field is shaped and the light intensity distribution is bifocal to prepare a type II dual-line waveguide with the bi-line spacing conforming to the set high temperature resistance and low loss. For example, when a 20 μm type II bilinear waveguide needs to be prepared, the relevant phase distribution and the required phase plate are obtained by using the bifocal phase formula, and the phase plate is loaded on the spatial light modulator, and the Gaussian beam is spatially light modulated. After shaping, a dual-focus three-dimensional focal field with an interval of 20 μm can be obtained, and the sample to be processed can be processed with the shaped laser beam, and a type II dual-line waveguide with a dual-line interval of 20 μm can be obtained.

The embodiment of the present application uses a spatial light modulator to shape the original ellipsoid light intensity distribution after the Gaussian beam is focused into a three-dimensional optical focal field with a bifocal light intensity distribution along the laser propagation direction, and the laser beam after shaping by the focal field is shaped The sample to be processed is scanned to obtain a type II bifilar waveguide in a single scan. Compared with the traditional method of preparing the type II bifilar waveguide by scanning the two damage traces of the type II bifilar waveguide in turn by scanning in two scans, the optical waveguide processing method proposed in the embodiment of the present application is faster. Further, in the present application, by loading the phase information into the spatial light modulator, a bifocal laser beam that can be shaped to conform to a specific focal field distribution can be obtained, and as long as the phase information is adjusted, a bifocal three-dimensional focal field with different intervals can be shaped, Thus, type II bifilar waveguides with different bifilar spacings are prepared.

In the embodiment of the present application, the laser beam after focal field shaping is used to perform multiple in-situ scanning processing on the sample to be processed, so as to accumulate and enhance the stress field around the damage trace of the type II bifilar waveguide, so as to offset the damage caused by high temperature annealing. After stress erasing, the waveguide can still confine light well with low transmission loss. A type II bifilar waveguide with high temperature resistance and low loss is prepared.

Another embodiment of the present application proposes a method for determining optimal processing parameters.

First select the femtosecond laser pulse repetition frequency and center wavelength to be used. In the case of determining the processing wavelength, pulse width, repetition frequency and focusing conditions, the parameters affecting the guided wave performance include: repetition frequency, pulse energy, scanning speed ( That is, the moving speed of the displacement platform), the double-line interval, the length of the waveguide, and the number of in-situ repeated scans.

In view of this, the present application takes each parameter affecting the performance of the waveguide as an invariant in turn; wherein, the parameters affecting the performance of the waveguide include: pulse energy, scanning speed, double line spacing, waveguide line length, and the number of repeated scanning; The numerical values of the parameters affecting the performance of the waveguide are obtained, and multiple sets of parameter combinations are obtained; each set of parameter combinations is used as a processing parameter in turn, and the laser beam after the focal field shaping is used to scan the reference sample to obtain multiple reference waveguides; The characterization analysis results of the plurality of reference waveguides are used to determine the optimal combination of processing parameters. The reference sample is the sample used in the determination of optimal processing parameters.

In one example of the present application, the applicant selected the femtosecond laser pulse repetition frequency for processing as 100 kHz and the center wavelength as 1030 nm. In order to prepare a single-mode high-performance waveguide with low transmission loss and high temperature resistance, 0.5 mm/ s, 1mm/s, 2mm/s, 3mm/s, 3.5mm/s, 4mm/s, 5mm/s, 10mm/s, 40mm/s scanning speed, double line interval selection 10μm, 15μm, 20μm, 26μm, 30μm, 35μm, the longitudinal length of the waveguide is 12μm, 16μm, 20μm, the number of repeated scans is selected once, twice, three times, four times, and five times, and the pulse energy is changed in the range of 0.96 ~ 1.26μJ. Use the control variable method to change the above parameter combinations respectively for processing.

The examples of this application propose a set of optimal processing parameters for preparing a type II dual-line optical waveguide with high temperature resistance and low loss: the pulse energy is 1.16 μJ, the scanning speed is 3 mm/s, the spacing between the dual lines is 20 μm, and the longitudinal length of the waveguide is 16 μm , repeat the scan three times.

According to the above optimal processing parameters, the sample to be processed is processed by the laser beam after focal field shaping, and the high temperature resistant type II double-wire waveguide A is obtained. In the examples of this application, the light guiding performance of the high temperature resistant type II bifilar waveguide A before and after high temperature annealing is analyzed. After ensuring that the waveguide mode captured by the CCD is single mode, the insertion loss, coupling loss, and Fresnel loss are calculated respectively, and the final result is obtained. its transmission loss. Among them, in the high temperature annealing experiment, the temperature rise at 0-500°C was set to be completed within 30 minutes, the temperature rise at 500°C-1000°C was completed within 50 minutes, and the temperature was cooled after heating at a high temperature of 1000°C for 3 hours. .

Figure 4 is a micrograph of the cross-sectional morphology of the type II bifilar waveguide A before high temperature annealing. Figure 5 is a micrograph of the cross-sectional morphology of the type II bifilar waveguide A after high temperature annealing. Fig. 6 is the distribution diagram of the guided mode of the optical fiber under V polarization. Fig. 7 is the mode field distribution diagram of the type II bifilar waveguide A in the input fiber guided mode under V polarization before high temperature annealing. Fig. 8 is the mode field distribution diagram of the type II bifilar waveguide A in the input fiber guided mode under V polarization after high temperature annealing.

10 μm described in FIGS. 4 and 5 is the scale bar size; 5 μm described in FIGS. 6 to 8 is the scale bar size. The direction of the arrow indicates the polarization direction of the injected laser light, that is, the V polarization.

According to the analysis of Fig. 6 and Fig. 7, it is obtained that the insertion loss of type II bifilar waveguide A before high temperature annealing is 2.99dB, the coupling loss of mode mismatch is 1.28dB, and the Fresnel reflection loss is 0.35dB/facet×2facet=0.7dB , the transmission loss is 0.67dB/cm. Analysis of Fig. 6 and Fig. 8 shows that the insertion loss of type II bifilar waveguide A after high temperature annealing is 3.41dB, the coupling loss of mode mismatch is 1.61dB, the Fresnel reflection loss is 0.7dB, and the transmission loss is 0.73dB/ cm.

By comparing the loss data before high temperature annealing and after high temperature annealing, the change of transmission loss of type II bifilar waveguide A under V polarization before and after annealing is 9%. The waveguide transmission loss is small. It can be seen that the parameter combination described in the embodiments of the present application can successfully complete the preparation of the sapphire high temperature resistant and low loss type II double-wire optical waveguide.

Based on the same inventive concept, an embodiment of the present application provides an optical waveguide processing system. FIG. 9 is a schematic diagram of a processing device of the optical waveguide processing system according to the embodiment of the present application. The optical waveguide processing system includes the processing device shown in FIG. 9 .

The processing device includes: Pharos femtosecond laser, X10468-02 spatial light modulator and three-dimensional displacement platform of non-contact air-floating table;

the femtosecond laser is used to generate a Gaussian beam;

The spatial light modulator is used for shaping the focal field of the Gaussian beam to obtain a three-dimensional focal field with a bifocal light intensity distribution along the laser propagation direction;

The three-dimensional displacement platform is controlled by a computer, and the computer receives user instructions and controls the translation platform to move the sample to be processed in the XYZ three-dimensional space according to the user's instructions. The sample to be processed is processed by using the high temperature resistant type II bifilar waveguide processing method described in any of the above embodiments of the present application to obtain a type II bifilar waveguide.

The processing device also includes: a CCD camera;

The CCD camera is used to observe the processing situation of the sample to be processed in real time; the processing situation refers to whether the laser beam after the focal field shaping is focused on the sample to be processed to form a focus.

The processing device also includes a half-wave plate, a Glan-Taylor polarizing prism, a lens group, a 4f lens system, a lens L ₁ , a reflecting mirror M ₁ , a reflecting mirror M ₂ , a dichroic mirror M ₃ and an LED illumination light source. The half-wave plate is combined with the Glan-Taylor polarizing prism to modulate the output optical power of the Gaussian beam; the lens group is used to expand the Gaussian beam; the 4f lens system is used to reduce the beam after shaping; the mirror M ₁ , the mirror _M2 is used to adjust the propagation direction _of the laser beam; the dichroic mirror M3 is used to ensure the high transmittance of the laser while reflecting part of the light into the CCD, so as to observe the processing situation of the sample to be processed in real time; LED The light source is used to illuminate the position of the sample to be processed, so that the sample to be processed is visible.

FIG. 10 is a schematic diagram of an apparatus for testing optical waveguide performance according to an embodiment of the present application, and the testing apparatus for optical waveguide performance is also called a waveguide characterization system. As shown in Figure 10, the test device includes: a fiber-coupled laser, a single-mode fiber, a waveguide, a laser spot analyzer, a power meter, and a focusing objective lens. By placing the type II bifilar waveguide processed in any of the above embodiments of the present application at the position of the waveguide in the waveguide characterization system, the purpose of comprehensively characterizing and analyzing the light guiding performance and loss of the type II bifilar waveguide can be achieved.

Among them, the fiber-coupled laser is used to emit a continuous laser with a wavelength of 785nm. The continuous laser is directly introduced into the fiber array of the single-mode fiber connected to it, and the fiber array is infinitely close to the end face of the sample, so that the laser beam is coupled to the waveguide inside the sample. middle. Since the dimensions of the fiber core and the waveguide are in the order of micrometers, the alignment and coupling are very difficult. In this embodiment of the present application, a six-axis precision displacement adjustment stage (MAX603D/M, Thorlabs) is used to precisely adjust the three-dimensional position of the fiber array and each The pitch angle of the direction.

The light output from the other end of the waveguide is received by a focusing objective lens, where the objective lens has a numerical aperture of 0.45, and is imaged on a laser spot analyzer. For the output light in the 785nm band, the laser spot analyzer (LaserCam-HR II 2/3) can record and analyze the weak image signal, observe the intensity change of the laser in real time and acquire the spot image at a high frame rate. 2D and 3D topography of the spot.

Various losses of the waveguide placed in the waveguide characterization system can be easily measured and calculated by the above-mentioned fiber coupling method.

As for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the partial description of the method embodiment.

Based on the same inventive concept, another embodiment provides a high temperature resistant type II bifilar waveguide, and the high temperature resistant and low loss type II bifilar waveguide is processed by the high temperature resistant type II optical waveguide described in any of the above embodiments of the present application method to get.

The high temperature resistant type II bifilar waveguide prepared in the present application has the characteristics of high temperature resistance and low loss.

Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once the basic inventive concepts are known. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the embodiments of the present application.

Finally, it should also be noted that, in this document, the terms "comprising", "comprising" or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements is not only Include those elements, but also include other elements not expressly listed or inherent to such process, method, article or terminal equipment. Without further limitation, an element defined by the phrase "comprises a..." does not preclude the presence of additional identical elements in the process, method, article or terminal device comprising said element.

The above is a detailed introduction to a high temperature resistant type II optical waveguide processing method and system and a high temperature resistant type II dual-wire waveguide provided by the application. At the same time, for those skilled in the art, according to the idea of the application, there will be changes in the specific implementation and application scope. To sum up, the content of this specification should not be construed as a limitation to the application.

Claims (6)

1. A high temperature resistant type II optical waveguide processing method, characterized in that the method comprises: get a Gaussian beam; Using a spatial light modulator to shape the focal field of the Gaussian beam to obtain a three-dimensional focal field with a bifocal light intensity distribution along the laser propagation direction; Using the laser beam after focal field shaping, and considering the optimal selection of the parameters of the longitudinal line length of the waveguide and the number of in-situ repeated scans, the sample to be processed is scanned in-situ for many times, and the double-line interval is obtained in line with the set high temperature resistance. And has a low-loss type II bifilar waveguide; The spacing of the bifocal points of the three-dimensional focal field is the same as the bilinear spacing of the waveguide; The longitudinal length of the waveguide affects the performance of the waveguide, and the longitudinal length of the waveguide is selected to be 16 μm; Determine the focal field information required for processing the waveguide according to the double-line spacing of the waveguide required by the user; The focal field information is calculated by using the analytical bifocal phase formula, and a phase distribution showing bifocals on a lateral plane is obtained; wherein, the lateral plane is a plane perpendicular to the laser propagation direction; According to the phase distribution, a bifocal phase plate is obtained; loading the bifocal phase plate onto the spatial light modulator; The focal field shaping of the Gaussian beam is carried out by using a spatial light modulator, and a three-dimensional focal field with a bifocal intensity distribution along the laser propagation direction is obtained, including: Using the spatial light modulator loaded with the bifocal phase plate to perform focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field with bifocal light intensity distribution along the laser propagation direction; Using the focal field shaped laser beam to perform multiple in-situ scanning processing on the sample to be processed, a type II dual-wire waveguide with high temperature resistance and low loss is obtained, including: Using the focal field shaped laser beam whose bifocal distribution conforms to the phase distribution, the sample to be processed is subjected to multiple in-situ scanning processing to obtain the type II bilinear waveguide with bilinear spacing conforming to the phase distribution; wherein , the multiple in-situ scanning processing is used to accumulate and enhance the stress field around the damage trace of the type II bifilar waveguide, so that the type II bifilar waveguide can offset the stress erasing caused by high temperature annealing , the confinement effect on light reaches a preset requirement; wherein, the preset requirement means that the change of the waveguide transmission loss before and after high temperature annealing is within 20%. 2 . The high temperature resistant type II optical waveguide processing method according to claim 1 , wherein the method further comprises: 3 . Taking each parameter of the parameters affecting the waveguide performance as an invariant in turn; wherein, the parameters affecting the waveguide performance include: pulse energy, scanning speed, double line spacing, waveguide line length, and the number of repeated scans; respectively changing the values of the parameters affecting the waveguide performance to obtain multiple sets of parameter combinations; Taking each group of parameter combinations as processing parameters in turn, the reference sample is scanned by the laser beam after focal field shaping, and multiple reference waveguides are obtained; According to the characterization analysis results of the plurality of reference waveguides, an optimal combination of processing parameters is determined. 3. The high temperature resistant type II optical waveguide processing method according to claim 2, wherein the optimal processing parameter combination is: The pulse energy was 1.16 μJ, the scanning speed was 3 mm/s, the double-line spacing was 20 μm, the longitudinal line length of the waveguide was 16 μm, and the in-situ scanning was repeated three times. 4. A high temperature resistant type II optical waveguide processing system, characterized in that the system comprises: a processing device, the processing device comprising: a femtosecond laser, a spatial light modulator and a three-dimensional displacement platform; the femtosecond laser is used to generate a Gaussian beam; The spatial light modulator is used for shaping the focal field of the Gaussian beam to obtain a three-dimensional focal field with a bifocal light intensity distribution along the laser propagation direction; The three-dimensional displacement platform is controlled by a computer and is used to move the sample to be processed, and the sample to be processed is processed by the high temperature resistant type II optical waveguide processing method according to any one of claims 1 to 3, so as to obtain a double wire The interval conforms to the set type II bifilar waveguide; The spacing of the bifocal points of the three-dimensional focal field is the same as the bilinear spacing of the waveguide; The longitudinal length of the waveguide affects the performance of the waveguide, and the longitudinal length of the waveguide is selected to be 16 μm. 5. The high temperature resistant type II optical waveguide processing system according to claim 4, wherein the processing system further comprises a device: a CCD camera; The CCD camera is used to observe the processing situation of the sample to be processed in real time; the processing situation refers to whether the laser beam after focal field shaping is focused on the sample to be processed to form a focus. 6 . A high temperature resistant type II bifilar waveguide, characterized in that, it is prepared by using any one of the high temperature resistant type II optical waveguide processing methods of claims 1 to 3 .

Images