阅读说明：本技术 一种基于光热敏折变玻璃的波导光栅耦合器及其制备方法 (Waveguide grating coupler based on photo-thermal sensitive refraction glass and preparation method thereof ) 是由 刘春晓 陈静怡 于 2019-11-26 设计创作，主要内容包括：本发明揭示了一种基于光热敏折变玻璃的波导光栅耦合器及其制备方法,该波导光栅耦合器,包括衬底材料、脊型光波导结构和光栅,所述衬底材料为光热敏折变玻璃,脊型光波导结构通过离子注入和飞秒激光烧蚀技术制备于衬底材料表面,光栅通过飞秒激光刻写技术集成制备于脊型光波导结构表面。本发明只需要运用离子注入和飞秒激光加工技术就可以实现脊型波导光栅耦合器的制备。飞秒激光加工技术既可以完成脊型波导的制备又能刻写光栅,一举两得,制备流程更加简单便捷。(The invention discloses a waveguide grating coupler based on photo-thermal sensitive refraction glass and a preparation method thereof. The invention can realize the preparation of the ridge waveguide grating coupler only by applying the ion implantation and femtosecond laser processing technology. The femtosecond laser processing technology can finish the preparation of the ridge waveguide and can write the grating, thereby achieving two purposes at one stroke and being simpler and more convenient in the preparation process.)

1. The utility model provides a waveguide grating coupler based on photosensitive glass that rolls over of light and heat which characterized in that: the optical fiber grating structure comprises a substrate material (1), a ridge type optical waveguide structure (2) and a grating (3), wherein the substrate material is photo-thermal sensitive conversion glass, the ridge type optical waveguide structure is prepared on the surface of the substrate material through ion implantation and femtosecond laser ablation technologies, and the grating is integrally prepared on the surface of the ridge type optical waveguide structure through the femtosecond laser writing technology.

2. A preparation method of a waveguide grating coupler based on photo-thermal sensitive refraction glass is characterized by comprising the following steps: the method comprises the following steps:

s1: sample pretreatment

Cutting the photo-thermal sensitive conversion glass to a proper size, and carrying out surface optical polishing and cleaning treatment;

s2: preparation of planar waveguide structure

Placing the photo-thermal sensitive conversion glass sample cut in the step S1 into an ion accelerator, selecting proper injection conditions for ion injection, and finally bombarding the surface of the sample by ions to form a planar waveguide layer;

s3: preparation of ridge waveguide structure

A laser light source 7 is emitted by a laser system 4, and the light source is focused on a sample which is made into a planar waveguide through a microobjective; and the sample 5 is positioned on the three-dimensional moving platform 6, and the sample is ablated by femtosecond laser to form a ridge waveguide structure by using the computer to control shutter opening and the three-dimensional moving platform.

S4: annealing treatment

Putting the ridge waveguide sample prepared in the step S3 into an annealing furnace for annealing treatment, and finally naturally cooling to room temperature;

s5: femtosecond laser writing grating

And longitudinally writing on the surface of the formed ridge waveguide by using femtosecond laser, preparing a grating structure, and finally obtaining the waveguide grating coupler based on the photothermal sensitive conversion glass.

3. The method of claim 2, wherein the method comprises: in step S1, the photothermographic conversion glass sample is cut to 10.0X 5.0X 1.0mm³The size of (2).

4. The method of claim 2, wherein the method comprises: in step S2, the ion implantation includes light ion implantation and heavy ion implantation.

5. The method of claim 4, wherein the method comprises: the light ion implantation is performed on hydrogen ions with the implantation energy of 400-550 keV and the implantation dosage of 1 x 10¹⁶～1×10¹⁷ions/cm²And the injected ion beam current is in the range of 100 nA.

6. The method of claim 4, wherein the method comprises: the heavy ion implantation is carried out by selecting carbon ions with implantation energy of 1 MeV-8 MeV and implantation dosage of 1 × 10¹³～5×10¹⁵ions/cm²And the injected beam current is in the range of 50 nA.

7. The method of claim 2, wherein the method comprises: in the step S3, the laser system is Ti: sapphire laser system. In the above Ti: parameters of femtosecond laser pulse in a Sapphire laser system are 800nm in wavelength, 1kHz in pulse repetition frequency and 220fs in pulse width, and ablation treatment is carried out on a sample at a constant scanning speed.

8. The method of claim 2, wherein the method comprises: in the step S4, the annealing condition is that the annealing treatment is carried out for 1-2 hours at 200-400 ℃.

9. The method of claim 2, wherein the method comprises: in step S5, the grating period of the waveguide-grating coupler is a uniform period, and the grating duty cycle is 0.5.

Technical Field

The invention relates to a waveguide grating coupler based on photo-thermal sensitive catadioptric glass and a preparation method thereof, which can be used in the technical field of integrated optics.

Background

The grating coupler is one of important photonic devices in the field of integrated optics, and is also a light beam coupler with practical value in optical interconnection. It diffracts the optical signal through the grating structure so that obliquely incident light is coupled into the waveguide. Compared with other couplers, the grating coupler realizes optical signal input or output coupling by using a vertical diffraction optical field of the optical waveguide, avoids the need of an accurate optical adjusting frame for adjustment in the traditional end face coupling process, and simplifies coupling operation to a great extent.

The waveguide grating coupler has the advantages of small volume, light weight, easy integration and the like due to the waveguide structure, and meanwhile, the quality of the optical waveguide directly influences the quality of the whole device and even the system, so that how to prepare the optical waveguide with excellent performance becomes a research hotspot.

As an important material modification method, the ion implantation technology has been developed into a relatively mature waveguide preparation method due to the advantages of wide material applicability, good controllability, strong repeatability, adjustable implantation temperature and the like; moreover, the ion implantation technology and the femtosecond laser ablation technology are combined to prepare the ridge type optical waveguide (IEEE Photonics Journal 10(5)1-7(2018)) with the two-dimensional optical waveguide structure on the optical material.

The bulk grating coupler is a kind of grating coupler, which can improve coupling efficiency by implementing periodic variation of refractive index inside a waveguide or fabricating a grating having inclined stripes, but the bulk grating coupler is easily limited by materials and fabrication processes. In recent years, photo-thermal sensitive refractive index (PTR) glass attracts much attention, which is a novel recording material grating material, wherein photosensitive and thermosensitive factors are added into the traditional microcrystalline glass, and the refractive index of the glass is permanently changed through ultraviolet exposure and heat treatment. The appearance of the material overcomes the technical defects of the traditional volume grating recording medium, and is an inexhaustible multifunctional material for preparing a diffraction optical device; however, no report has been made of waveguide grating couplers based on PTR glass.

The conventional grating preparation method is a two-beam interference method, but has the defect that the interference of the beams is difficult to control, so that a simpler preparation method needs to be researched and developed. Considering that the femtosecond laser processing technology can write and ablate a sample so as to process any pattern (including a waveguide structure and a grating structure), is very suitable for processing a three-dimensional complex structure, and does not need a mask, the waveguide grating prepared by the technology has the effect of simplifying the process.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a waveguide grating coupler based on photothermal sensitive refractive glass and a preparation method thereof.

The purpose of the invention is realized by the following technical scheme: the utility model provides a waveguide grating coupler based on photosensitive converting glass of light and heat, includes substrate material, ridge type optical waveguide structure and grating, the substrate material is photosensitive converting glass of light and heat, and ridge type optical waveguide structure prepares on substrate material surface through ion implantation and femto second laser ablation technique, and the grating prepares on ridge type optical waveguide structure surface through femto second laser inscription technique integration.

The invention also discloses a preparation method of the waveguide grating coupler based on the photothermal sensitive conversion glass, which comprises the following steps:

s1: sample pretreatment

Cutting the photo-thermal sensitive conversion glass to a proper size, and carrying out surface optical polishing and cleaning treatment;

s2: preparation of planar waveguide structure

Placing the photo-thermal sensitive conversion glass sample cut in the step S1 into an ion accelerator, selecting proper injection conditions for ion injection, and finally bombarding the surface of the sample by ions to form a planar waveguide layer;

s3: preparation of ridge waveguide structure

A laser light source 7 is emitted by a laser system 4, and the light source is focused on a sample which is made into a planar waveguide through a microobjective; and the sample 5 is positioned on the three-dimensional moving platform 6, and the sample is ablated by femtosecond laser to form a ridge waveguide structure by using the computer to control shutter opening and the three-dimensional moving platform.

S4: annealing treatment

Putting the ridge waveguide sample prepared in the step S3 into an annealing furnace for annealing treatment, and finally naturally cooling to room temperature;

s5: femtosecond laser writing grating

And longitudinally writing on the surface of the formed ridge waveguide by using femtosecond laser, preparing a grating structure, and finally obtaining the waveguide grating coupler based on the photothermal sensitive conversion glass.

Preferably, in the step S1, the photothermographic conversion glass sample is cut to 10.0 × 5.0 × 1.0mm³The size of (2).

Preferably, in the S2 step, the ion implantation includes light ion implantation and heavy ion implantation.

Preferably, the light ion implantation is performed on hydrogen ions with implantation energy of 400-550 keV and implantation dose of 1 x 10¹⁶～1×10¹⁷ions/cm²And the injected ion beam current is in the range of 100 nA.

Preferably, the heavy ion implantation is performed by selecting carbon ions with implantation energy of 1 MeV-8 MeV and implantation dose of 1 × 10¹³～5×10¹⁵ions/cm²And the injected beam current is in the range of 50 nA.

Preferably, in the step S3, the laser system is a Ti: sapphire laser system. In the above Ti: parameters of femtosecond laser pulse in a Sapphire laser system are 800nm in wavelength, 1kHz in pulse repetition frequency and 220fs in pulse width, and ablation treatment is carried out on a sample at a constant scanning speed.

Preferably, in the step S4, the annealing condition is that the annealing treatment is carried out for 1-2 h at 200-400 ℃.

Preferably, in step S5, the grating period of the waveguide-grating coupler is a uniform period, and the grating duty cycle is 0.5.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects: the invention can realize the preparation of the ridge waveguide grating coupler only by applying the ion implantation and femtosecond laser processing technology. The femtosecond laser processing technology can finish the preparation of the ridge waveguide and can write the grating, thereby achieving two purposes at one stroke and being simpler and more convenient in the preparation process.

The technical scheme prepares the waveguide grating coupler on the basis of the photo-thermal sensitive conversion glass, and the photo-thermal sensitive conversion glass becomes an important substrate material for preparing a diffraction optical device due to the excellent optical characteristics of the photo-thermal sensitive conversion glass.

The grating coupler is integrated on the two-dimensional ridge waveguide, and the two-dimensional optical waveguide structure has higher light limitation degree and can achieve higher energy density.

The photo-thermal sensitive catadioptric waveguide grating coupler in the technical scheme has the advantages of high integration level and miniaturization besides meeting the most basic input and output coupling functions. The coupler is prepared by adopting ion implantation and femtosecond laser processing technologies, and the grating coupler prepared by the technical scheme has high integration level, small and light weight and simple preparation process.

Drawings

FIG. 1 is a schematic structural diagram of a waveguide grating coupler based on photothermal sensing conversion glass according to the present invention.

FIG. 2 is a schematic view of the preparation process of the present invention.

FIG. 3 is a schematic view of the preparation process of the present invention.

FIG. 4 is a schematic diagram of femtosecond laser micromachining according to the present invention.

Detailed Description

Objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments. The embodiments are merely exemplary for applying the technical solutions of the present invention, and any technical solution formed by replacing or converting the equivalent thereof falls within the scope of the present invention claimed.

The invention discloses a waveguide grating coupler based on photo-thermal sensitive refraction glass, as shown in figure 1, the waveguide grating coupler comprises a substrate material 1, a ridge type optical waveguide structure 2 and a grating 3, wherein the substrate material is the photo-thermal sensitive refraction glass, the ridge type optical waveguide structure is prepared on the surface of the substrate material through ion implantation and femtosecond laser ablation technologies, and the grating is integrally prepared on the surface of the ridge type optical waveguide structure through a femtosecond laser writing technology.

The invention also discloses a preparation method of the waveguide grating coupler based on the photothermal sensitive conversion glass, which comprises the following steps:

s1: sample pretreatment

Cutting the photo-thermal sensitive conversion glass to a proper size, and carrying out surface optical polishing and cleaning treatment;

specifically, a PTR glass sample is cut to an appropriate size and its surface to be processed is optically polished, while the polished sample needs to be subjected to a cleaning treatment before an ion implantation operation.

S2: preparation of planar waveguide structure

And (3) putting the photo-thermal sensitive conversion glass sample cut in the step S1 into an ion accelerator, selecting proper implantation conditions for ion implantation, and finally bombarding the surface of the sample by ions to form a planar waveguide layer.

And carrying out ion implantation on the pretreated sample to obtain the planar waveguide structure. In step S2, the ion implantation includes light ion implantation and heavy ion implantation. The light ion implantation is performed on hydrogen ions with the implantation energy of 400-550 keV and the implantation dosage of 1 x 10¹⁶～1×10¹⁷ions/cm²And the injected ion beam current is in the range of 100 nA. The heavy ion implantation is carried out by selecting carbon ions with implantation energy of 1 MeV-8 MeV and implantation dosage of 1 × 10¹³～5×10¹⁵ions/cm²And the injected beam current is in the range of 50 nA.

The energy required for ion implantation ranges from keV to MeV, and there are two methods of implementing light ion implantation and heavy ion implantation. And selecting proper injection conditions, performing ion bombardment on the surface of the sample by using a 2X 1.7MV serial accelerator, and finally forming the planar optical waveguide on the polished surface of the sample. In the injection process, the normal direction of the sample surface and the direction of the incident ion beam form an angle of 7 degrees so as to avoid channeling effect, and the injected ion beam current is limited in a certain range so as to prevent the heat effect caused in the injection process.

S3: preparation of ridge waveguide structure

Emitting laser beams through a laser system, and focusing the beams on a sample made into a planar waveguide through a microscope objective; the sample is positioned on the three-dimensional moving platform, and the sample is ablated by femtosecond laser to form a ridge waveguide structure by using the computer to control shutter opening and the three-dimensional moving platform.

Specifically, a sample of the planar optical waveguide structure was placed on a three-dimensional conditioning stage with a spatial resolution of 0.2 μm. By using Ti: the Sapphire laser system emits femtosecond laser pulses, which are focused by a 20-fold objective lens (n.a. ═ 0.4) onto the sample surface. And finally, ablating the original planar waveguide sample to form a ridge waveguide structure by using a computer to control shutter light opening and a three-dimensional moving platform.

S4: annealing treatment

And (4) putting the ridge waveguide sample prepared in the step S3 into an annealing furnace for annealing treatment, and finally naturally cooling to room temperature.

S5: femtosecond laser writing grating

And longitudinally writing on the surface of the formed ridge waveguide by using femtosecond laser, preparing a grating structure, and finally obtaining the waveguide grating coupler based on the photothermal sensitive conversion glass.

In step S1, the photothermographic conversion glass sample is cut to 10.0X 5.0X 1.0mm³The size of (2).

In step S3, the laser system is Ti: sapphire laser system. In the above Ti: parameters of femtosecond laser pulse in a Sapphire laser system are 800nm in wavelength, 1kHz in pulse repetition frequency and 220fs in pulse width, and ablation treatment is carried out on a sample at a constant scanning speed.

In the step S4, the annealing condition is that the annealing treatment is carried out for 1-2 hours at 200-400 ℃.

In step S5, the grating period of the waveguide-grating coupler is a uniform period, and the grating duty cycle is 0.5. The specific grating period depends on the wavelength of the transmitted optical signal.