CN112894128B

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

Info

Publication number: CN112894128B
Application number: CN202110148738.2A
Authority: CN
Inventors: 闫霖玉; 龚旗煌; 李焱; 李萌
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2022-06-17
Anticipated expiration: 2041-02-02
Also published as: CN112894128A

Abstract

The application provides a high-temperature resistant II-type optical waveguide processing method and system and a high-temperature resistant II-type double-line waveguide, and relates to the technical field of waveguide preparation. The problem of how to obtain high temperature resistant II type double-line waveguide fast can be solved. The method comprises the following steps: obtaining a Gaussian beam; performing focal field shaping on the Gaussian beam by using a spatial light modulator to obtain a three-dimensional optical focal field which is in double-focus light intensity distribution along the laser propagation direction; and performing in-situ scanning on the sample to be processed for multiple times by using the laser beam subjected to the focal field shaping to obtain the high-temperature-resistant low-loss type II double-line waveguide.

Description

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

Technical Field

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

Background

The waveguide is a basic unit of an integrated chip, and is often required to resist high temperature in extreme fields such as aerospace, and the working temperature of the optical waveguide which is often directly written by glass and polymer materials and is often adopted by researchers is limited, so that the direct writing of the high-performance high-temperature-resistant optical waveguide in materials such as sapphire and the like and the integrated photonic device are very necessary in extreme fields such as aerospace. The type I waveguide is extremely easy to erase at high temperature and is difficult to retain, so the related field adopts a stress-induced type II double-line waveguide.

The femtosecond laser direct writing prepared waveguide has the advantages of high flexibility, true three-dimension and the like, and the prepared optical waveguide has low transmission loss. However, in the conventional femtosecond laser direct writing type II waveguide manufacturing technology, a laser is used for processing a sample twice, and two damage traces are respectively obtained on the sample, so that a complete type II double-line waveguide is obtained. The process of scanning the sample twice is complex and takes a long time.

Therefore, how to rapidly obtain the II-type double-wire waveguide with high temperature resistance and low loss is an urgent problem to be solved in the related field.

Disclosure of Invention

The embodiment of the application provides a high-temperature resistant II-type optical waveguide processing method and system and a high-temperature resistant II-type double-line waveguide, and can solve the problem of how to rapidly prepare the high-temperature resistant low-loss II-type double-line waveguide.

A first aspect of an embodiment of the present application provides a method for processing a high-temperature resistant type ii optical waveguide, where the method includes:

obtaining a Gaussian beam;

performing focal field shaping on the Gaussian beam by using a spatial light modulator to obtain a three-dimensional optical focal field which is in double-focus light intensity distribution along the laser propagation direction;

and performing in-situ scanning on the sample to be processed for multiple times by using the laser beam subjected to the focal field shaping to obtain the high-temperature resistant II-type double-line waveguide.

Optionally, the method further comprises:

determining focal field information required when the waveguide is processed according to the waveguide double-line interval required by a user;

calculating the focal field information by using an analytic bifocal phase formula to obtain the phase distribution presenting bifocal points on a transverse plane; wherein the transverse plane is a plane perpendicular to the propagation direction of the laser light;

obtaining a bifocal phase plate according to the phase distribution;

loading the bifocal phase plate onto the spatial light modulator;

utilize spatial light modulator to carry out focus field shaping to the gaussian beam, obtain the three-dimensional light focus field that is the distribution of bifocal light intensity along laser propagation direction, include:

performing focal field shaping on the Gaussian beam by using the spatial light modulator loaded with the bifocal phase plate to obtain a three-dimensional optical focal field which is in bifocal light intensity distribution along the laser propagation direction;

or, a multifocal phase plate is obtained by calculating focusing field information by using an analytic multifocal phase formula, the multifocal phase plate is loaded to the spatial light modulator, and focal field shaping is carried out on the Gaussian beam to obtain a discrete circular three-dimensional optical focal field which is formed by multiple focuses and inclines along the vertical direction along the laser propagation direction.

Optionally, the laser beam shaped by the focal field is used to perform multiple in-situ scanning processing on a sample to be processed, so as to obtain the high-temperature-resistant low-loss type ii double-line waveguide, including:

performing in-situ scanning processing on a sample to be processed for multiple times by using the laser beam after the focal field shaping with bifocal light intensity distribution conforming to the phase information to obtain the high-temperature-resistant low-loss type II bifilar waveguide with bifilar intervals conforming to the phase information; the multiple in-situ scanning processing is used for performing accumulated enhancement on a stress field around a damage trace of the II-type double-line waveguide, so that after the II-type double-line waveguide counteracts stress erasure caused by high-temperature annealing, the constraint effect on light reaches a preset requirement; wherein the preset requirement means that the transmission loss variation of the waveguide before and after the high temperature annealing is within 20%.

Optionally, the method further comprises:

taking each parameter in the parameters influencing the waveguide performance as an invariant in turn; wherein the affecting waveguide performance parameters include: pulse energy, scanning speed, double-line interval, waveguide line length and repeated scanning times;

respectively changing the numerical values of the parameters influencing the waveguide performance to obtain a plurality of groups of parameter combinations;

sequentially combining each group of parameters as processing parameters, and scanning a reference sample by using the laser beam subjected to focal field shaping to obtain a plurality of reference waveguides;

and determining the optimal processing parameter combination according to the characterization analysis results of the plurality of reference waveguides.

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

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

the femtosecond laser is used for generating a Gaussian beam;

the spatial light modulator is used for performing focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field which is in double-focus light intensity distribution along the laser propagation direction;

the three-dimensional displacement platform is controlled by a computer for moving a sample to be processed and processing the sample to be processed using the method according to the first aspect of the present application to obtain a type ii bifilar waveguide.

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

the CCD camera is used for observing the processing condition of the sample to be processed in real time; the processing condition refers to whether the laser beam after being shaped by the focal field is focused on the sample to be processed to form a focal point.

In a third aspect of the embodiments of the present application, there is provided a type ii bifilar waveguide with high temperature resistance and low loss, which is prepared by the method according to the first aspect of the present application.

The spatial light modulator is used in the embodiment of the application, original ellipsoidal light intensity distribution of a Gaussian beam after being focused is shaped into a three-dimensional light focal field which is in double-focus light intensity distribution along the laser propagation direction, and a laser beam after being shaped by the focal field scans a sample to be processed so as to obtain the II-type double-line waveguide under the condition of single scanning. Compared with the traditional method that two damage traces of the II-type double-line waveguide are scanned in sequence by two times of scanning, the method for processing the optical waveguide provided by the embodiment of the application is faster. Furthermore, the double-focus laser beam which accords with the distribution of a specific focus field can be shaped by loading the phase information to the spatial light modulator, and the double-focus three-dimensional focus field with different intervals can be shaped by only adjusting the phase information, so that the II-type double-line waveguide with different double-line intervals can be prepared.

The laser beam after the focal field is shaped is adopted in the embodiment of the application, a sample to be processed is subjected to multiple in-situ scanning processing, so that the stress field around the damage trace of the II-type double-line waveguide is subjected to accumulated enhancement, the waveguide still can well restrict light after the stress caused by high-temperature annealing is counteracted and is erased, and the low-transmission loss is realized. Obtaining the II type double-line waveguide with high temperature resistance and low loss.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.

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

FIG. 2 is a schematic diagram of a bifocal phase plate obtained according to an example of the present application;

FIG. 3 is a simulated light intensity distribution diagram of a bifocal three-dimensional focal field in the yz plane obtained by using an exemplary focal field shaping method according to the present disclosure;

FIG. 4 is a cross-sectional topography micrograph of type II twin wire waveguide A prior to high temperature annealing;

FIG. 5 is a cross-sectional topography micrograph of type II twin wire waveguide A after high temperature annealing;

FIG. 6 is a diagram of guided mode distribution of optical fiber under V polarization;

FIG. 7 is a diagram showing the mode field distribution of type II twin-wire waveguide A in the input fiber guided mode under V polarization before high temperature annealing;

FIG. 8 is a diagram of the mode field distribution of type II twin-wire waveguide A after high temperature annealing in the input fiber guided mode under V polarization;

FIG. 9 is a schematic view of a processing apparatus of an optical waveguide processing system according to an embodiment of the present application;

FIG. 10 is a schematic view of an apparatus for testing optical conductivity according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Fig. 1 is a flowchart of steps of a method for processing a high temperature resistant type ii optical waveguide in an embodiment of the present application, and 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 II-type optical waveguide prepared by the method has the characteristics of high temperature resistance and low loss.

Step S11: a gaussian beam is obtained.

The output laser beam of the femtosecond laser is generally a Gaussian beam.

In an example of the present application, a femtosecond laser with an output center wavelength of 1030nm is used to generate a gaussian beam, a half-wave plate and a glan-taylor polarizer are used to modulate the output optical power of the gaussian beam, and the gaussian beam is expanded by a pair of lens groups and then is incident on a spatial light modulator.

Step S12: and performing focal field shaping on the Gaussian beam by using a spatial light modulator to obtain a three-dimensional light focal field which is in bifocal light intensity distribution along the laser propagation direction.

The focal field shaping of the Gaussian beam means that the original ellipsoidal light intensity distribution of the focused Gaussian beam is shaped into a three-dimensional light focal field which is in double-focus light intensity distribution along the laser propagation direction. The shaped laser beam is focused into a sample to be processed through an objective lens, and the sample to be processed is moved through a three-dimensional displacement platform, so that two damage traces can be obtained simultaneously.

Another embodiment of the present application provides a specific implementation method for performing focal field shaping on a gaussian beam.

Step S12-1: and determining the required focal field information when the waveguide is processed according to the waveguide double-line interval required by a user.

In one example of the present application, the determined focal field information is the bifilar spacing of the resulting high temperature resistant type ii bifilar waveguide, depending on the waveguide performance desired by the user.

Step S12-2: calculating the focal field information by using an analytic bifocal phase formula to obtain the phase distribution presenting bifocal points on a transverse plane; wherein the transverse plane is a plane perpendicular to the propagation direction of the laser light.

The bifocal phase equation is divided into a term that controls movement of the focal point in the XY plane and a term that controls movement of the focal point in the Z direction.

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

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

In one example of the present application, the bifocal phase equation controls the movement of the focal point in the XY plane by the term shown in equation (1):

wherein x is₀And y₀Is the coordinate of each point on the entrance pupil surface of the focusing objective lens, Δ x is the offset of the focal point from the center of the defocused field in the x direction after being focused by the objective lens, Δ y is the offset of the focal point from the center of the defocused field in the y direction after being focused by the objective lens, NA is the numerical aperture of the focusing objective lens, and λ₀Is the central wavelength of the laser beam in vacuum, and R is the entrance pupil radius of the focusing objective lens; n is_tIs the refractive index of the sample to be processed.

The term for controlling the movement of the focus in the Z direction is expressed by the following equation (2):

wherein, the delta z is the offset of the focal point from the center of the defocused field in the z direction after the objective lens focuses.

(1) The formulas (1) and (2) can be expanded to a multi-focus phase formula, Gaussian beams are shaped into discrete circular three-dimensional optical focal fields which are formed by multiple focuses and inclined along the vertical direction along the laser propagation direction, and then the depressed cladding waveguide is prepared through single scanning.

Step S12-3: and obtaining 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 according to an example of the present application, the phase plate shown in fig. 2 being capable of producing a bifocal light intensity distribution at 15 μm intervals. Adjusting the phase information of the separation between the bifocal points also results in a phase distribution exhibiting bifocal points at a separation of 20 μm and 26 μm. The multifocal phase plate and the bifocal phase plate bear different phase information, and the multifocal phase formula focusing field information obtained by expanding the formulas (1) and (2) can be specifically calculated to obtain multifocal phase distribution.

Step S12-4: loading the bifocal phase plate onto the spatial light modulator; or, loading the multi-focal phase plate onto the spatial light modulator.

The spatial light modulator is connected with a computer, and the phase plates in the bifocal phase distribution are input into the computer so as to fulfill the aim of loading the bifocal phase plates on the spatial light modulator.

Step S12-5: performing focal field shaping on the Gaussian beam by using the spatial light modulator loaded with the bifocal phase plate to obtain a three-dimensional optical focal field which is in bifocal light intensity distribution along the laser propagation direction; or, the spatial light modulator loaded with the multi-focus phase plate is used for carrying out focal field shaping on the Gaussian beam to obtain a discrete circular three-dimensional light focal field which is formed by multiple focuses and inclines along the vertical direction along the laser propagation direction.

FIG. 3 is a simulated yz-plane intensity distribution diagram of a three-dimensional focal field shaped by a focal field according to 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 the three-dimensional focal field corresponding to the light intensity distribution conforming to the set phase information can be obtained by using the focal field shaping method provided by the embodiment of the present application. The lateral coordinate of fig. 3 is a coordinate of spatial distribution of the focal field in the y direction, and the longitudinal coordinate is a coordinate of spatial distribution of the focal field in the z direction.

Step S13: and performing in-situ scanning on the sample to be processed for multiple times by using the laser beam subjected to the focal field shaping to obtain the high-temperature-resistant low-loss type II double-line waveguide.

By adopting the method for processing the waveguide, the laser beam which is shaped by the focal field and has the double-focus light intensity distribution is used for scanning the sample to be processed in situ for multiple times, and the II-type double-line waveguide which has two damage traces and is high-temperature-resistant and low-loss can be obtained simultaneously. The stress field around the damage trace of the II-type double-line waveguide can be cumulatively enhanced by multiple in-situ scanning processing, so that the constraint effect of the II-type double-line waveguide on light can meet the preset requirement after the II-type double-line waveguide counteracts stress erasure caused by high-temperature annealing. Wherein the preset requirement means that the transmission loss variation of the waveguide before and after the high temperature annealing is within 20%.

One example of the present application selects pure sapphire with a large refractive index (about 1.77) as a sample to be processed, and the pure sapphire has a high temperature resistance.

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

And performing in-situ scanning processing on a sample to be processed for multiple times by using a laser beam with bifocal light intensity distribution after the focal field is shaped, and preparing to obtain the II-type bifilar waveguide with the bifilar interval conforming to the set high-temperature-resistant low-loss. Illustratively, when a 20 μm type ii double-line waveguide needs to be prepared, a double-focus phase formula is used to obtain a relevant phase distribution and a required phase plate, the phase plate is loaded on a spatial light modulator, a gaussian beam is shaped by the spatial light modulator to obtain a double-focus three-dimensional focal field with a spacing of 20 μm, and a sample to be processed is processed by the shaped laser beam to obtain a type ii double-line waveguide with a spacing of 20 μm between double lines.

The spatial light modulator is used in the embodiment of the application, original ellipsoidal light intensity distribution of a Gaussian beam after being focused is shaped into a three-dimensional light focal field which is in double-focus light intensity distribution along the laser propagation direction, and a laser beam after being shaped by the focal field scans a sample to be processed so as to obtain the II-type double-line waveguide under the condition of single scanning. Compared with the traditional method for preparing the II-type double-line waveguide by scanning twice and scanning two damage traces of the II-type double-line waveguide in sequence, the optical waveguide processing method provided by the embodiment of the application is faster. Furthermore, the double-focus laser beam which accords with the distribution of a specific focus field can be shaped by loading the phase information to the spatial light modulator, and the double-focus three-dimensional focus field with different intervals can be shaped by only adjusting the phase information, so that the II-type double-line waveguide with different double-line intervals can be prepared.

The laser beam after the focal field is shaped is adopted in the embodiment of the application, a sample to be processed is subjected to multiple in-situ scanning processing, so that the stress field around the damage trace of the II-type double-line waveguide is subjected to accumulated enhancement, the waveguide still can well restrict light after the stress caused by high-temperature annealing is counteracted and is erased, and the low-transmission loss is realized. And preparing the II-type double-line waveguide with high temperature resistance and low loss.

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

Firstly, selecting the repetition frequency and the central wavelength of the femtosecond laser pulse to be used, and under the condition of determining the processing wavelength, the pulse width, the repetition frequency and the focusing condition, the parameters influencing the guided wave performance comprise: repetition frequency, pulse energy, scan speed (i.e. displacement stage movement speed), double line spacing, waveguide line length, number of in-situ rescanning times.

In view of this, the present application takes each of the parameters that affect waveguide performance as an invariant in turn; wherein the affecting waveguide performance parameters include: pulse energy, scanning speed, double-line interval, waveguide line length and repeated scanning times; respectively changing the numerical values of the parameters influencing the waveguide performance to obtain a plurality of groups of parameter combinations; sequentially combining each group of parameters as processing parameters, and scanning a reference sample by using the laser beam shaped by the focal field to obtain a plurality of reference waveguides; and determining the optimal processing parameter combination according to the characterization analysis results of the plurality of reference waveguides. The reference sample is the sample used in the process of determining the optimum processing parameters.

In an example of the present application, the femtosecond laser pulse repetition frequency selected by the applicant for processing is 100kHz, the center wavelength is 1030nm, in order to prepare a single-mode high-performance waveguide with low transmission loss and high temperature resistance, scanning speeds of 0.5mm/s, 1mm/s, 2mm/s, 3mm/s, 3.5mm/s, 4mm/s, 5mm/s, 10mm/s and 40mm/s are respectively selected, 10 μm, 15 μm, 20 μm, 26 μm, 30 μm and 35 μm are selected at double-line intervals, the longitudinal line length of the waveguide is 12 μm, 16 μm and 20 μm, and the number of repeated scanning is selected once, twice, three times, four times and five times, and the pulse energy is changed within the range of 0.96-1.26 μ J. And respectively changing the parameter combinations by using a control variable method for processing.

The embodiment of the application provides a group of optimal processing parameters for preparing the high-temperature-resistant low-loss type II double-line optical waveguide: the pulse energy was 1.16 muj, the scanning speed was 3mm/s, the double line interval was 20 μm, the longitudinal line length of the waveguide was 16 μm, and the scanning was repeated three times.

And according to the optimal processing parameters, processing the sample to be processed by adopting the laser beam after the focal field shaping to obtain the high-temperature resistant II-type double-line waveguide A. The embodiment of the application analyzes the light guide performance before and after high-temperature annealing of the high-temperature resistant II-type double-line waveguide A, and after the waveguide mode shot by the CCD is a single mode, the insertion loss, the coupling loss and the Fresnel loss of the waveguide mode are respectively calculated, and finally the transmission loss of the waveguide mode is obtained. In the high-temperature annealing experiment, the temperature rise of 0-500 ℃ is set to be completed within 30 minutes, the temperature rise of 500-1000 ℃ is set to be completed within 50 minutes, and the temperature is reduced and cooled after the heating is carried out for 3 hours at the high temperature of 1000 ℃. .

FIG. 4 is a cross-sectional topography micrograph of type II twin wire waveguide A prior to high temperature annealing. FIG. 5 is a micrograph of the cross-sectional profile of type II twin wire waveguide A after high temperature annealing. FIG. 6 is a diagram of guided mode distribution of a fiber under V polarization. FIG. 7 is a diagram showing the mode field distribution of the type II twin waveguide A under the V polarization of the guided mode of the input fiber before high temperature annealing. FIG. 8 is a diagram showing the mode field distribution of type II twin-wire waveguide A in the input fiber guided mode under V polarization after high temperature annealing.

10 μm shown in FIGS. 4 and 5 is a scale size; the 5 μm shown in FIGS. 6 to 8 is a scale size. The arrow direction indicates the polarization direction of the injected laser light, i.e., V polarization.

Analysis of fig. 6 and 7 yields: the insertion loss of the II-type double-line waveguide A before high-temperature annealing is 2.99dB, the coupling loss of mode mismatch is 1.28dB, the Fresnel reflection loss is 0.35dB/facet multiplied by 2facet which is 0.7dB, and the transmission loss is 0.67 dB/cm. Analysis of fig. 6 and 8 yields: after high-temperature annealing, the insertion loss of the II-type double-line waveguide A is 3.41dB, the mode mismatched coupling loss is 1.61dB, the Fresnel reflection loss is 0.7dB, and the transmission loss is 0.73 dB/cm.

By comparing the loss data before and after high-temperature annealing, the change of the transmission loss of the type II double-line waveguide A under V polarization before and after annealing is 9%, so that the type II double-line waveguide A is high-temperature resistant, and the transmission loss of the waveguide is small no matter before and after high-temperature annealing. Therefore, the parameter combination described in the embodiment of the application can successfully complete the preparation of the sapphire high-temperature-resistant low-loss type II double-line optical waveguide.

Based on the same inventive concept, an optical waveguide processing system is provided in the embodiments of the present application, and fig. 9 is a schematic view of a processing apparatus of the optical waveguide processing system in the embodiments of the present application, where the optical waveguide processing system includes the processing apparatus shown in fig. 9.

The processing device comprises: a Pharos femtosecond laser, an X10468-02 spatial light modulator and a three-dimensional displacement platform of a non-contact air bearing platform;

the femtosecond laser is used for generating a Gaussian beam;

the three-dimensional displacement platform is controlled by a computer, and the computer receives a user instruction and controls the translation platform to move the sample to be processed in the XYZ three-dimensional space according to the user instruction. The sample to be processed is processed by the high-temperature resistant type II duplex waveguide processing method according to any embodiment of the present application, so as to obtain a type II duplex waveguide.

The processing device further includes: a CCD camera;

the CCD camera is used for observing the processing condition of the sample to be processed in real time; the processing condition refers to whether the laser beam after the focal field shaping is focused on the sample to be processed to form a focal point.

The processing device also comprises a half-wave plate, a Glan Taylor polarizing prism, a lens group, a 4f lens system and a lens L₁Mirror M₁Mirror M₂Dichroic mirror M₃And an LED illumination source. The half-wave plate is combined with the Glan Taylor polarizing prism to modulate the output light power of the Gaussian beam; the lens group is used for expanding Gaussian beams; the 4f lens system is used for beam-shrinking the shaped laser beam; reflector M₁Mirror M₂For adjusting the propagation direction of the laser beam; dichroic mirror M₃The CCD is used for reflecting part of light into the CCD while ensuring high laser transmissivity so as to observe the processing condition of the sample to be processed in real time; the LED light source is used for illuminating the position of the sample to be processed, so that the sample to be processed is visible.

Fig. 10 is a schematic view of a testing apparatus for optical conductivity, which is also called a waveguide characterization system according to an embodiment of the present application. As shown in fig. 10, the test apparatus includes: the device comprises a fiber coupled laser, a single mode fiber, a waveguide, a laser spot analyzer, a power meter and a focusing objective lens. The II-type double-line waveguide processed and obtained by any embodiment of the method is placed at the waveguide position in the waveguide characterization system, so that the purposes of comprehensively characterizing and analyzing the light guiding performance and the loss of the II-type double-line waveguide can be achieved.

The fiber coupling laser is used for emitting continuous laser with the wavelength of 785nm, the continuous laser is directly guided into a fiber array of a single-mode fiber connected with the continuous laser, the fiber array is infinitely close to the end face of a sample, and laser beams are coupled into a waveguide in the sample. Because the sizes of the optical fiber core and the waveguide are both in the micrometer range, the difficulty of alignment coupling is very high, and the three-dimensional position of the optical fiber array and the pitch angle in each direction are accurately adjusted by adopting a six-axis precise displacement adjusting table (MAX603D/M, Thorlabs).

The light output from the other end of the waveguide was received by a focusing objective lens having a numerical aperture of 0.45 and imaged on a laser spot analyzer. For the output light with the wave band of 785nm, the laser spot analyzer (LaserCam-HR II 2/3) can record and analyze weak image signals, observe the intensity change of laser in real time, acquire spot images at a high frame frequency and directly give the two-dimensional and three-dimensional shapes of spots.

The optical fiber coupling method can be used for conveniently measuring and calculating various losses of the waveguide placed in the waveguide characterization system.

For the system embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

Based on the same inventive concept, another embodiment provides a high-temperature resistant type ii duplex waveguide, which is obtained by the high-temperature resistant type ii optical waveguide processing method according to any of the embodiments described above in the present application.

The high-temperature-resistant II-type double-wire waveguide prepared by the method has the characteristics of high temperature resistance and low loss.

While preferred embodiments of the present application have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the true scope of the embodiments of the application.

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

The method and the system for processing the high-temperature resistant II-type optical waveguide and the high-temperature resistant II-type dual-line waveguide provided by the application are introduced in detail, and the description of the embodiment is only used for helping to understand the method and the core idea of the application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A method for processing high-temperature resistant II-type optical waveguide is characterized by comprising the following steps:

obtaining a Gaussian beam;

performing in-situ scanning on a sample to be processed for multiple times by using the laser beam shaped by the focal field and considering the optimal selection of parameters of the longitudinal line length of the waveguide and the in-situ repeated scanning times to obtain a II-type double-line waveguide which has high temperature resistance and low loss and has double-line intervals meeting the set requirements;

the interval of the bifocal points of the three-dimensional optical focal field is the same as the bifilar interval of the waveguide;

the waveguide longitudinal line length influences the waveguide performance, and is selected to be 16 microns;

obtaining a bifocal phase plate according to the phase distribution;

loading the bifocal phase plate onto the spatial light modulator;

the laser beam after the focal field shaping is adopted to carry out a plurality of times of in-situ scanning processing on a sample to be processed to obtain the high-temperature resistant low-loss type II double-line waveguide, which comprises the following steps:

performing in-situ scanning processing on a sample to be processed for multiple times by using the laser beams after the focal field shaping with bifocal point distribution conforming to the phase distribution to obtain the type II bifilar waveguide with bifilar intervals conforming to the phase distribution; the multiple in-situ scanning processing is used for performing accumulated enhancement on a stress field around a damage trace of the II-type double-line waveguide, so that after the II-type double-line waveguide counteracts stress erasure caused by high-temperature annealing, the constraint effect on light reaches a preset requirement; wherein the preset requirement means that the waveguide transmission loss change is within 20% before and after the high-temperature annealing.

2. The method of claim 1, further comprising:

taking each parameter influencing the waveguide performance parameter as an invariant in turn; wherein the affecting waveguide performance parameters include: pulse energy, scanning speed, double-line interval, waveguide line length and repeated scanning times;

3. The method of claim 2, wherein the optimal processing parameters comprise:

the pulse energy is 1.16 muJ, the scanning speed is 3mm/s, the interval of the double lines is 20μm, the length of the longitudinal line of the waveguide is 16μm, and the in-situ repeated scanning is carried out for three times.

4. A high temperature resistant type ii optical waveguide processing system, said system comprising: a processing device, the processing device comprising: the system comprises a femtosecond laser, a spatial light modulator and a three-dimensional displacement platform;

the femtosecond laser is used for generating a Gaussian beam;

the spatial light modulator is used for carrying out focal field shaping on the Gaussian beam to obtain a three-dimensional optical focal field which is in double-focus light intensity distribution along the laser propagation direction;

the three-dimensional displacement platform is controlled by a computer and is used for moving a sample to be processed, and the sample to be processed is processed by adopting the high-temperature resistant type II optical waveguide processing method according to any one of claims 1 to 3, so that a type II double-line waveguide with the double-line interval conforming to the set value is obtained;

the waveguide longitudinal line length influences the waveguide performance, and is selected to be 16 mu m.

5. The system of claim 4, further comprising means for: a CCD camera;

6. A high-temperature resistant II-type double-line waveguide which is characterized by being prepared by the processing method of the high-temperature resistant II-type optical waveguide according to any one of claims 1 to 3.