CN114878505A - A Chip-Type Micro Air Cell Based on Plane Bending Optical Waveguide - Google Patents

Abstract

The chip-type micro gas cell based on the plane-curved optical waveguide provided in the embodiment of the present invention, a silicon-based substrate, an optical waveguide lower cladding layer arranged on the silicon-based substrate, a core layer arranged on the optical waveguide lower cladding layer, The core layer is a ridge-shaped optical waveguide structure, including a wide-mouth laser incident waveguide, a waveguide mode converter, a straight waveguide, a curved waveguide and a wide-mouth laser output waveguide, and an air-chamber interaction cavity arranged on the core layer. The cavity is provided with an air inlet and an air outlet, and the air chamber interacts with the cavity and the core layer to form a closed space. By adopting a combination of straight waveguide and curved waveguide to form a time-delay line curved waveguide, the interaction between the gas to be tested and the evanescent field is increased, and the optical power limiting factor is improved. On the premise of not increasing the length of the optical waveguide, the equivalent The optical path length is improved by integrating a micro-air chamber interaction cavity on the optical waveguide sensor chip to improve the level of system integration.

Description

A chip-type micro gas cell based on a plane-curved optical waveguide

technical field

The invention relates to the field of gas detection, in particular to a chip-type micro gas chamber and an infrared gas detection device based on a plane-curved optical waveguide.

Background technique

Infrared gas detection is to use the absorption spectrum characteristics of the gas to be measured in the near-infrared or mid-infrared to realize the determination of the concentration of the gas to be measured. It has the characteristics of high detection sensitivity, fast response, and good stability. It is widely used in detection, industrial gas detection and other fields. The sensing part of the infrared gas detection system mainly includes the infrared laser emission module, the gas chamber and the photoelectric conversion module. The design of the gas chamber is directly related to the detection accuracy, detection sensitivity, volume weight and cost of the detection system. Traditional gas cells mostly use discrete optical components, which are large in size and poor in integration. Compared with the planar optical waveguide sensing gas cell, the volume is very small, and it can also be integrated with laser light sources and detectors on-chip.

Based on this, several methods for detecting gas concentration based on planar optical waveguide gas cells have been proposed, which can be roughly divided into two categories: refractive index sensing and optical absorption sensing. Refractive index sensing is based on changes in the refractive index of the gas being measured, resulting in changes in the frequency or phase of the output light. Compared with refractive index sensing, the waveguide sensor based on laser absorption spectrum is selective, because each gas to be tested has a unique absorption spectrum. measure the gas concentration.

In order to reduce the lower limit of detection in the existing technology, according to the Beer-Lambert law, it is necessary to increase the optical path length, that is, the length of the interaction between the light and the gas to be measured, which will bring about a large transmission loss. In the optical waveguide gas sensor, the gas to be tested acts as the cladding of the waveguide and interacts with the evanescent field of the waveguide. As long as the optical power limit factor of the gas to be tested is increased, it means that the light can fully interact with the gas to be tested, increasing the equivalent light length, reduce system noise and lower detection limit.

SUMMARY OF THE INVENTION

In view of this, embodiments of the present invention provide a chip-type micro gas cell and an infrared gas detection device based on a plane-curved optical waveguide.

In a first aspect, the present invention provides a chip-type micro gas cell based on a plane-curved optical waveguide, comprising:

silicon-based substrate;

an optical waveguide lower cladding layer disposed on the silicon-based substrate;

a core layer arranged on the lower cladding layer of the optical waveguide, the core layer is a ridge-shaped optical waveguide structure, including a wide-mouth laser incident waveguide, a waveguide mode converter, a straight waveguide, a curved waveguide and a wide-mouth laser output waveguide;

An air-chamber interaction cavity is provided on the core layer, the air-chamber interaction cavity is provided with an air inlet and an air outlet, and the air-chamber interaction cavity and the core layer form a closed space.

As an optional solution, the optical waveguide lower cladding layer is a low-refractive-index, low-loss inorganic material or a polymer thin film material with a uniform thickness formed on the silicon-based substrate.

As an optional solution, the lower cladding layer of the optical waveguide is made of SiO ₂ material.

As an optional solution, the core layer is made of inorganic material, and the preparation process is chemical vapor deposition, electron beam evaporation or sputtering process.

As an optional solution, the core layer is made of polymer film material, and the preparation process is spin coating and baking.

As an optional solution, the shape formed by the straight waveguide and the curved waveguide is a delay line waveguide.

As an optional solution, the air-chamber interaction cavity is square, circular or oval.

As an optional solution, the material of the air-chamber interaction cavity is a polymer material or glass.

As an optional solution, the air chamber interaction cavity is made of polydimethylsiloxane PDMS material.

As an optional solution, the core layer is a ridge optical waveguide structure, the ridge optical waveguide structure is an inverted trapezoidal structure design, and the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode converter, the wide-mouth laser incident waveguide is connected to the first waveguide mode converter, the first waveguide mode converter is connected to the straight waveguide, the curved waveguide is a semicircular waveguide, and the straight waveguide is connected to the straight waveguide. The curved waveguides are connected to form a series S-shaped delay line structure, the straight waveguides are connected to the second waveguide mode converter, the second waveguide mode converter is connected to the wide-mouth laser output waveguide, and the first waveguide mode converter is connected to the wide-mouth laser output waveguide. A waveguide mode converter has the same structure as the second waveguide mode converter but the light passing directions are opposite, and the wide-mouth laser input waveguide has the same structure as the wide-mouth laser output waveguide.

As an optional solution, the core layer is a ridge optical waveguide structure, the ridge optical waveguide structure is an inverted trapezoidal structure design, and the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode a converter, the wide-mouth laser incident waveguide is connected to the first waveguide mode converter, the first waveguide mode converter is connected to the straight waveguide, and the curved waveguide is composed of a plurality of semicircular waveguides with different radii , the straight waveguide is connected with the curved waveguide to form a Taichi type helical delay line structure, the straight waveguide is connected with the second waveguide mode converter, and the second waveguide mode converter is connected with the wide-mouth laser The output waveguide is connected, the first waveguide mode converter and the second waveguide mode converter have the same structure but opposite light passing directions, and the wide-mouth laser incident waveguide has the same structure as the wide-mouth laser output waveguide.

As an optional solution, the core layer is a ridge optical waveguide structure and a slit optical waveguide structure, the slit optical waveguide structure is arranged on the straight waveguide and the curved waveguide, and the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode converter, the wide-mouth laser incident waveguide is connected with the first waveguide mode converter, the first waveguide mode converter is connected with the straight waveguide, the curved The waveguide is a semicircular waveguide, the straight waveguide is connected to the curved waveguide to form a series S-shaped delay line structure, the straight waveguide is connected to the second waveguide mode converter, and the second waveguide mode converter is connected to the second waveguide mode converter. The wide-mouth laser output waveguide is connected, the first waveguide mode converter and the second waveguide mode converter have the same structure but opposite light passing directions, and the wide-mouth laser incident waveguide has the same structure as the wide-mouth laser output waveguide .

In a second aspect, the present invention provides an infrared gas detection device having the above-mentioned chip-type micro gas cell based on a plane-curved optical waveguide.

The chip-type micro gas cell and the infrared detection device based on the plane-curved optical waveguide provided in the embodiment of the present invention include a silicon-based substrate, an optical waveguide lower cladding layer disposed on the silicon-based substrate, and disposed on the optical waveguide. The core layer on the lower cladding layer of the waveguide, the core layer is a ridge-shaped optical waveguide structure, including a wide-mouth laser incident waveguide, a waveguide mode converter, a straight waveguide, a curved waveguide and a wide-mouth laser output waveguide, arranged on the core layer The air-chamber interaction cavity above the air-chamber interaction cavity is provided with an air inlet and an air outlet, and the air-chamber interaction cavity and the core layer form a closed space. By adopting the combination of straight waveguide and curved waveguide to form a time delay line curved waveguide, the interaction between the gas to be tested and the evanescent field is increased, the optical power limiting factor is improved, and the equivalent optical waveguide length is increased without increasing the length of the optical waveguide. Optical path length, integrated miniature gas chamber interaction cavity on the optical waveguide sensor chip, the infrared gas detection gas chamber can be chipped and integrated, and the subsequent laser light source, gas chamber, detector and control circuit can be integrated miniature Design provides the solution.

Description of drawings

FIG. 1 is a schematic structural diagram of a chip-type micro gas cell based on a plane-curved optical waveguide provided in an embodiment of the present invention;

2 is a schematic structural diagram of an optical waveguide structure in a chip-type micro gas cell based on a plane-curved optical waveguide provided in an embodiment of the present invention;

FIG. 3 is a simulated optical field distribution diagram of a ridge-shaped optical waveguide structure in a sensing region of a chip-type micro-air chamber based on a plane-curved optical waveguide provided in an embodiment of the present invention;

FIG. 4 is a schematic SEM photograph of a ridge-shaped optical waveguide structure in the sensing region of another chip-type micro air cell based on a plane-curved optical waveguide provided in an embodiment of the present invention;

5 is a schematic structural diagram of a chip-type micro gas cell based on a plane-curved optical waveguide provided in an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an optical waveguide structure in another chip-type micro-air chamber based on a plane-curved optical waveguide according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of another chip-type micro air cell based on a plane-curved optical waveguide provided in an embodiment of the present invention;

8 is a schematic structural diagram of an optical waveguide structure in a chip-type micro-air chamber based on a plane-curved optical waveguide provided in an embodiment of the present invention;

FIG. 9 is a top view of another optical waveguide structure in a chip-type micro gas cell based on a plane-curved optical waveguide provided in an embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The terms "first", "second", "third", "fourth", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that data so used may be interchanged under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

1 and 2, the present invention provides a chip-type micro gas cell based on a plane-curved optical waveguide, including:

Silicon-based substrate 1;

an optical waveguide lower cladding layer 2 disposed on the silicon-based substrate;

The core layer 3 arranged on the lower cladding layer 2 of the optical waveguide, the core layer 3 is a ridge-shaped optical waveguide structure, including a wide-mouth laser incident waveguide 301, a waveguide mode converter, a straight waveguide 303, a curved waveguide 304 and a wide-mouth laser incident waveguide 301. A laser output waveguide 306;

The air chamber interaction cavity 4 arranged on the core layer, the air chamber interaction cavity 4 is provided with an air inlet 5 and an air outlet 6, the air inlet 5 is used to input the gas to be measured, and the air outlet 6 For discharging the gas to be tested, the gas chamber interaction cavity 4 and the core layer 3 form a closed space.

As an optional solution, the optical waveguide lower cladding layer 2 is a low-refractive index, low-loss inorganic material or a polymer thin film material, a dielectric film or a polymer film with a uniform thickness formed on the silicon-based substrate 1 The minimum thickness of the film is to prevent the optical field of the optical waveguide from leaking to the substrate layer. In this embodiment, the lower cladding layer 2 of the optical waveguide can be made of SiO ₂ material, and the thickness can be 2 μm, which is not limited.

The material of the core layer 3 can be made of inorganic material or polymer material, and the core layer 3 is made of inorganic material, and the preparation process is chemical vapor deposition, electron beam evaporation or sputtering process. The core layer 3 is made of a polymer film material, and the preparation process is spin coating and baking. Those of ordinary skill in the art should understand the relevant preparation process, and will not be repeated here.

In the embodiment of the present invention, the shape formed by the straight waveguide 303 and the curved waveguide 304 is a delay line waveguide, and a delay line curved waveguide structure is adopted to increase the interaction between the gas to be measured and the evanescent field, and improve its optical power The limiting factor is to increase the equivalent optical path length without increasing the length of the optical waveguide, and integrate the micro-chamber interaction cavity on the optical waveguide sensor chip, which truly makes the infrared gas detection gas chamber chip-like and integrated. It provides a solution for the integrated miniature design of the subsequent laser light source, gas chamber, detector and control circuit.

The gas-chamber interaction cavity 4 is square, circular or elliptical, and can cover the gas sensing area formed by the straight waveguide 303 and the curved waveguide 304 . The material of the gas-chamber interaction cavity 4 can be a polymer material, glass or other material that does not affect the propagation of the laser light in the optical waveguide, and can be selected according to the needs, which is not limited

In this embodiment, the air chamber interaction cavity 4 is made of polydimethylsiloxane PDMS material.

In some embodiments, the core layer 3 is a ridge optical waveguide structure, the ridge optical waveguide structure is an inverted trapezoidal structure design, and the waveguide mode converter includes a first waveguide mode converter 302 and a second waveguide mode Converter 305, the wide-mouth laser incident waveguide 301 is connected to the first waveguide mode converter 302, the first waveguide mode converter 302 is connected to the straight waveguide 303, and the curved waveguide 304 is a semicircular waveguide , the straight waveguides 303 are arranged in parallel and spaced apart, the straight waveguides 303 and the curved waveguides 304 are connected to form a series S-shaped delay line structure, the straight waveguides 303 and the second waveguide mode converter 305 connected, the second waveguide mode converter 305 is connected to the wide-mouth laser output waveguide 306, the first waveguide mode converter 302 and the second waveguide mode converter 305 have the same structure but opposite light passing directions, so The wide-mouth laser incident waveguide 301 has the same structure as the wide-mouth laser output waveguide 306 .

1, specifically, the ridge-shaped optical waveguide is an SOI optical waveguide, which includes a silicon-based substrate 1 in order from bottom to top; the optical waveguide lower cladding layer 2 placed on the silicon-based substrate is made of _SiO2 material , the thickness is 2 μm; the core layer 3 placed on the lower cladding layer 2 of the optical waveguide is made of Si material, and the thickness is 500 nm; the gas chamber interaction cavity 4 placed on the core layer 3 is made of polydimethylsilicon Oxane (PDMS) material, the air inlet 5 and the air outlet 6 placed on the air chamber interaction cavity are made of PDMS material.

As shown in FIG. 2 , the core layer 3 is a ridge-shaped optical waveguide structure, forming a series S-type delay line structure, the etching depth is 220 nm, and includes a wide-mouth laser incident waveguide 301 with a width of 15 μm, a first waveguide mode converter 302, The length is 300 μm, the waveguide width is transitioned from 15 μm to 1.5 μm, the plurality of straight waveguides 303, the length is 1718 μm, the waveguide width is 1.5 μm, the plurality of curved waveguides 304 are semi-circular waveguides, the bending radius is 50 μm, the waveguide width is 1.5 μm, the straight waveguides 303 and the bending The waveguides 304 are connected end to end to form a series S-shaped delay line structure. The second waveguide mode converter 305 has the same structure as the first waveguide mode converter 302, and the light passing direction is opposite; the structure of the wide-mouth laser output waveguide 306 is the same as that of the wide-mouth laser incident waveguide 301 The structure is the same.

Figure 3 shows the simulated light field distribution diagram of the simulated ridge-shaped optical waveguide structure in the sensing area. The ridge shape is an inverted trapezoid structure with a width of 1.5 μm on the upper side and a width of 1.65 μm on the lower side. Figure 4 shows the SEM photo of the simulated ridge-shaped optical waveguide structure in the sensing region. On this basis, a chip-type micro gas chamber has been successfully developed and used for methane gas detection, and the test proves that the effect is feasible.

With reference to FIG. 5 , in other embodiments, the core layer is a ridge optical waveguide structure, the ridge optical waveguide structure is an inverted trapezoidal structure design, and the waveguide mode converter includes a first waveguide mode converter 302 and a second waveguide mode converter 305, the wide-mouth laser incident waveguide 301 is connected with the first waveguide mode converter 302, the first waveguide mode converter 302 is connected with the straight waveguide 303, the curved The waveguide 304 is composed of a plurality of semi-circular waveguides with different radii. The straight waveguide 303 and the curved waveguide 304 are connected to form a Taichi spiral delay line structure. The straight waveguide 303 and the second waveguide mode converter 305 connected, the second waveguide mode converter 305 is connected to the wide-mouth laser output waveguide 306, the first waveguide mode converter 302 is the same as the second waveguide mode converter 305 but the light passing direction is opposite, the The wide-mouth laser incident waveguide 301 has the same structure as the wide-mouth laser output waveguide 306 .

As shown in FIG. 5 , specifically, the ridge-shaped optical waveguide is an SU-8 optical waveguide, which includes a silicon-based substrate 1 in order from bottom to top; the optical waveguide lower cladding layer 2 placed on the silicon-based substrate is made of SiO ₂ material, with a thickness of 2 μm; the core layer 3 placed on the lower cladding layer 2 of the optical waveguide is made of SU-8 material, with a thickness of 3 μm; the gas chamber interaction cavity 4 placed on the core layer 3, It is made of polydimethylsiloxane (PDMS) material, and the air inlet 5 and the air outlet 6 placed on the left and right sides of the air chamber interaction cavity 4 are all made of PDMS material.

As shown in FIG. 6 , the core layer 3 is a ridge-shaped optical waveguide structure, which constitutes a Taichi-type helical delay line structure with an etching depth of 1 μm, including a wide-mouth laser incident waveguide 301 with a width of 15 μm; a first waveguide mode converter 302 , the length is 300 μm, the waveguide width transitions from 15 μm to 2.5 μm, the multiple straight waveguides 303 are 1718 μm in length and the waveguide width is 2.5 μm, and the multiple curved waveguides 304 are composed of multiple semi-circular waveguides with different radii, and the bending radii are 50 μm and 75 μm respectively. and 100 μm, and the waveguide width is 2.5 μm; the straight waveguide 303 and the curved waveguide 304 are connected end to end to form a Taichi spiral delay line structure, the second waveguide mode converter 305 has the same structure as the first waveguide mode converter 302, and the light passing direction is opposite; The structure of the wide-mouth laser output waveguide 306 is the same as that of the wide-mouth laser input waveguide 301 .

In still other embodiments, the core layer is a ridge optical waveguide structure and a slit optical waveguide structure, the slit optical waveguide structure is arranged on the straight waveguide 303 and the bending wave 304, and the waveguide mode is converted The device includes a first waveguide mode converter 302 and a second waveguide mode converter 305, the wide-mouth laser incident waveguide 301 is connected to the first waveguide mode converter 302, and the first waveguide mode converter 302 is connected to the The straight waveguide 303 is connected, the curved waveguide 304 is a semi-circular waveguide, the straight waveguide 303 and the curved waveguide 304 are connected to form a series S-type delay line structure, the straight waveguide 303 and the second waveguide mode converter 305 is connected, the second waveguide mode converter 305 is connected with the wide-mouth laser output waveguide 306, the first waveguide mode converter 302 and the second waveguide mode converter 305 have the same structure but the light passing direction is opposite, The wide-mouth laser incident waveguide 301 has the same structure as the wide-mouth laser output waveguide 306 .

As shown in FIG. 7 , the optical waveguide is an SOI optical waveguide, which specifically includes a silicon-based substrate 1 from bottom to top; the optical waveguide lower cladding layer 2 placed on the silicon-based substrate is made of SiO ₂ material and has a thickness of 2 μm; The core layer 3 placed on the lower cladding layer 2 of the optical waveguide is made of Si material with a thickness of 220 nm; the gas chamber interaction cavity 4 placed on the core layer 3 is made of polydimethylsiloxane (PDMS) The air inlet 5 and the air outlet 6 placed on the air chamber interaction cavity 4 are made of PDMS material.

8 and 9, the core layer 3 adopts a ridge optical waveguide and a slit optical waveguide structure to form a series S-type delay line structure, and the etching depth is 220 nm, including the wide-mouth laser incident waveguide 301, the ridge light Waveguide structure, width 8μm; first waveguide mode converter 302, length 300μm, ridge optical waveguide structure, waveguide width transition from 8μm to 1.1μm; multiple straight waveguides 303, slit waveguide structure, length 1718μm, total waveguide width 1.1 μm, the width of the high refractive index region on both sides is 500 nm, the width of the middle slit is 100 nm, the plurality of curved waveguides 304 are semi-circular waveguides, the bending radius is 50 μm, the width of the waveguide is 1.1 μm, the width of the high refractive index region on both sides is 500 nm, and the width of the middle slit is 100 nm The straight waveguide 303 and the curved waveguide 304 are connected end to end to form a series S-type delay line structure, the second waveguide mode converter 305 has the same structure as the first waveguide mode converter 302, and the light passing direction is opposite; the wide-mouth laser output waveguide 306 has the same structure as The structure of the wide-mouth laser incident waveguide 301 is the same.

The chip-type micro gas cell based on the plane-curved optical waveguide provided in the embodiment of the present invention forms a time-delay line-type curved waveguide by combining a straight waveguide and a curved waveguide, thereby increasing the interaction between the gas to be measured and the evanescent field, and improving its performance. The optical power limiting factor increases the equivalent optical path length without increasing the length of the optical waveguide, and integrates the micro-gas chamber interaction cavity on the optical waveguide sensing chip, so that the infrared gas detection gas chamber can be chipped, Integration provides a solution for the subsequent integrated miniature design of laser light source, gas chamber, detector and control circuit.

Correspondingly, the present invention provides an infrared gas detection device, which has the above-mentioned chip-type micro gas chamber based on a plane-curved optical waveguide, which can realize the chip-based and integrated infrared gas detection gas chamber, which can be used for subsequent laser light sources, gas The integrated miniature design of chamber, detector and control circuit provides the solution.

The above-mentioned specific embodiments do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. A chip type micro air chamber based on a planar bending optical waveguide is characterized by comprising:

a silicon-based substrate;

an optical waveguide lower cladding disposed on the silicon-based substrate;

the core layer is arranged on the optical waveguide lower cladding layer and is of a ridge optical waveguide structure and comprises a wide-mouth laser incident waveguide, a waveguide mode converter, a straight waveguide, a bent waveguide and a wide-mouth laser output waveguide;

the air chamber interaction cavity is arranged on the core layer, an air inlet and an air outlet are formed in the air chamber interaction cavity, and the air chamber interaction cavity and the core layer form a closed space in a surrounding mode.

2. The chip-type micro gas cell based on planar bending optical waveguide of claim 1, wherein the optical waveguide lower cladding layer is a low refractive index, low loss inorganic material or polymer thin film material of uniform thickness generated on the silicon-based substrate.

3. The chip-type micro gas cell based on planar bending optical waveguide as claimed in claim 1 or 2, wherein the optical waveguide lower cladding layer is made of SiO ₂ A material.

4. The chip type micro gas cell based on the planar bending optical waveguide as claimed in claim 1, wherein the core layer is made of inorganic material and is prepared by chemical vapor deposition, electron beam evaporation or sputtering.

5. The chip-type micro air cell based on the planar bending optical waveguide as claimed in claim 1, wherein the core layer is made of polymer film material and is prepared by spin coating and baking.

6. The chip-type micro gas cell based on planar curved optical waveguide as claimed in claim 1, wherein the straight waveguide and the curved waveguide are formed in the shape of a delay line waveguide.

7. The chip-type micro gas cell based on planar bending optical waveguide of claim 1, wherein the gas cell interaction cavity is square, circular or elliptical.

8. The chip-type micro gas cell based on planar bending optical waveguide of claim 1 or 7, wherein the material of the gas cell interaction cavity is polymer material or glass.

9. The chip-type micro gas cell based on planar bending optical waveguide of claim 1 or 7, wherein the gas cell interaction cavity is made of PDMS material.

10. The chip-type micro gas cell based on planar curved optical waveguide as claimed in claim 1, wherein the core layer is a ridge optical waveguide structure, the ridge optical waveguide structure is designed as an inverted trapezoid structure, the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode converter, the wide laser incident waveguide is connected to the first waveguide mode converter, the first waveguide mode converter is connected to the straight waveguide, the curved waveguide is a semicircular waveguide, the straight waveguide is connected to the curved waveguide to form a serial S-type delay line structure, the straight waveguide is connected to the second waveguide mode converter, the second waveguide mode converter is connected to the wide laser output waveguide, the first waveguide mode converter and the second waveguide mode converter are identical in structure but opposite in light passing direction, the wide-mouth laser incident waveguide and the wide-mouth laser output waveguide have the same structure.

11. The chip-type micro gas cell based on planar curved optical waveguide as claimed in claim 1, wherein the core layer is a ridge optical waveguide structure, the ridge optical waveguide structure is designed as an inverted trapezoid structure, the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode converter, the wide laser incident waveguide is connected to the first waveguide mode converter, the first waveguide mode converter is connected to the straight waveguide, the curved waveguide is composed of a plurality of semicircular waveguides with different radii, the straight waveguide is connected to the curved waveguide to form a tai-chi helical delay line structure, the straight waveguide is connected to the second waveguide mode converter, the second waveguide mode converter is connected to the wide laser output waveguide, the first waveguide mode converter and the second waveguide mode converter are identical in structure but opposite in light transmission direction, the wide-mouth laser incident waveguide and the wide-mouth laser output waveguide have the same structure.

12. The chip-type micro gas cell based on planar curved optical waveguide as claimed in claim 1, wherein the core layer is a ridge optical waveguide structure and a slit optical waveguide structure, the slit optical waveguide structure is disposed on the straight waveguide and the curved waveguide, the waveguide mode converter includes a first waveguide mode converter and a second waveguide mode converter, the wide laser incident waveguide is connected to the first waveguide mode converter, the first waveguide mode converter is connected to the straight waveguide, the curved waveguide is a semicircular waveguide, the straight waveguide is connected to the curved waveguide to form a serial S-type delay line structure, the straight waveguide is connected to the second waveguide mode converter, the second waveguide mode converter is connected to the wide laser output waveguide, the first waveguide mode converter is identical to the second waveguide mode converter in structure but opposite to the light transmission direction, the wide-mouth laser incident waveguide and the wide-mouth laser output waveguide have the same structure.

13. An infrared gas detection device, characterized in that, the chip-type micro gas cell based on the planar bending optical waveguide of any one of claims 1 to 12 is provided.

Images