CN111624702B - Orthogonal double-shaft aspheric optical fiber micro lens - Google Patents
Orthogonal double-shaft aspheric optical fiber micro lens Download PDFInfo
- Publication number
- CN111624702B CN111624702B CN202010389630.8A CN202010389630A CN111624702B CN 111624702 B CN111624702 B CN 111624702B CN 202010389630 A CN202010389630 A CN 202010389630A CN 111624702 B CN111624702 B CN 111624702B
- Authority
- CN
- China
- Prior art keywords
- fiber
- optical fiber
- elliptical core
- orthogonal biaxial
- aspheric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 142
- 239000000835 fiber Substances 0.000 claims abstract description 154
- 238000009792 diffusion process Methods 0.000 claims abstract description 55
- 238000009826 distribution Methods 0.000 claims abstract description 55
- 239000002019 doping agent Substances 0.000 claims abstract description 24
- 238000010438 heat treatment Methods 0.000 claims description 22
- 238000013461 design Methods 0.000 claims description 10
- 238000005520 cutting process Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 abstract description 31
- 238000004519 manufacturing process Methods 0.000 abstract description 21
- 230000010354 integration Effects 0.000 abstract description 4
- 238000003384 imaging method Methods 0.000 abstract description 3
- 238000012576 optical tweezer Methods 0.000 abstract description 3
- 238000002360 preparation method Methods 0.000 abstract description 3
- 230000003287 optical effect Effects 0.000 description 10
- 238000012545 processing Methods 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 9
- 230000008859 change Effects 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- 238000005253 cladding Methods 0.000 description 5
- 238000007493 shaping process Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000011161 development Methods 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000007516 diamond turning Methods 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 229910052732 germanium Inorganic materials 0.000 description 2
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000001459 lithography Methods 0.000 description 2
- 239000004005 microsphere Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 239000003981 vehicle Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007526 fusion splicing Methods 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 238000000025 interference lithography Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/028—Optical fibres with cladding with or without a coating with core or cladding having graded refractive index
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/028—Optical fibres with cladding with or without a coating with core or cladding having graded refractive index
- G02B6/0281—Graded index region forming part of the central core segment, e.g. alpha profile, triangular, trapezoidal core
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
Abstract
The invention provides an orthogonal biaxial aspheric optical fiber micro lens. The method is characterized in that: it is prepared by thermal diffusion of an elliptical core optical fiber. The orthogonal biaxial aspheric optical fiber micro lens is prepared by thermal diffusion in a constant temperature field, and after the elliptical core dopant of the finely designed elliptical core optical fiber is diffused, the refractive index distribution is changed into non-circumferential symmetric quasi-Gaussian distribution which can be equivalent to a micro lens. The invention provides a fiber-integrated orthogonal biaxial aspheric optical fiber micro lens, which has the advantages of simple manufacture and low cost. The preparation method can be used for preparing the fiber-integrated microlens, and can be widely applied to the fields of miniature endoscopes, cell biology optical fiber imaging systems, optical fiber optical tweezers systems, miniature unmanned aerial vehicles and the like of the orthogonal biaxial aspheric optical fiber microlens based on the fiber integration.
Description
(I) technical field
The invention relates to an orthogonal biaxial aspheric optical fiber micro lens, which can be used for preparing a fiber integrated micro lens and can be widely applied to the fields of miniature endoscopes, cell biological optical fiber imaging systems, optical fiber optical tweezers systems, miniature unmanned aerial vehicles and the like of the orthogonal biaxial aspheric optical fiber micro lens based on fiber integration.
(II) background of the invention
With the development of modern industry and scientific technology, people have gradually entered the information-based era. The rapid development of information technology requires that a complete information system can realize as many functions as possible in as small a space as possible, which requires that devices for realizing various functions be as small as possible, and the development is directed toward miniaturization and miniaturization.
The fiber-integrated micro-optical element has the advantages of small volume, light weight, flexible design and manufacture, low manufacturing cost, easy realization of arraying and batch production and the like, can realize the function which is difficult to realize by a common optical element, and has important application value in the fields of optical fiber communication, information processing, aerospace, biomedicine, laser technology, optical calculation and the like.
With the continuous and deep research, many methods for manufacturing micro-optical elements are proposed, mainly including semiconductor lithography, single-point diamond turning, electron beam etching, femtosecond laser direct writing, and the like. The semiconductor photoetching process needs to use a mask plate, and the microstructure is transferred onto the photoresist through development by utilizing ultraviolet light exposure. The method has mature process, is suitable for mass production and has low average cost. The defects that the processed structure only can be planar, multiple times of alignment are needed when a multi-stage structure is processed, the requirement on alignment precision is high, and the cost is increased sharply. The surface roughness of single-point diamond turning is small, the surface roughness is generally below 10nm, and the method is suitable for processing structures with any rotary appearance. The machining precision depends on the tool bit and the machine tool, the precision requirement on the machine tool is high, the machined material is limited, and the size of a machined structure cannot be too small. The electron beam etching is divided into a scanning type and a projection type, a mask plate is not needed in the scanning type, the alignment and the splicing are automatically controlled by a computer, and the processing precision is extremely high. The disadvantages are complex equipment, high cost, small single exposure area and too long time for manufacturing large-size structures. The projection type processing speed is fast, but the mask preparation is difficult. Both methods need to be carried out in vacuum, which greatly limits the application range. The femtosecond laser processing is a processing method of a non-contact high-precision micro-nano photoelectric device, and has strong universality on applicable materials. The defects are high equipment cost, complex processing technology and low processing efficiency.
Current lens systems are limited in shape and size due to manufacturing process concerns. Fabrication techniques for fiber integration of optical fibers with micro-optical elements have recently been proposed for fabrication of micro-optical elements directly on the end face of an optical fiber using different methods of fabrication techniques such as focused ion beam milling, interference lithography, nanoimprint techniques, lithography, polishing techniques, etc. However, they have the disadvantages of difficult processing, complicated manufacturing device, etc.
The thermal diffusion processing technology has the advantages of easiness in implementation, low cost, simplicity in operation and the like, and has great application potential in micro-electro-mechanical systems, optical integrated devices, optical communication and optical fiber sensing. The optical fiber is subjected to thermal diffusion treatment, so that smooth gradual change of the refractive index can be formed in a thermal diffusion processing area, and the smooth gradual change refractive index area has the effect of a micro lens. The finely designed elliptic core optical fiber is processed by thermal diffusion, and the fiber integrated orthogonal biaxial aspheric optical fiber micro lens can be prepared.
Patent CN01144937.3 discloses an optical fiber having a lens function and a method for manufacturing the same, which is effective for an optical fiber having an abrupt refractive index by using a graded-index optical fiber having a period length indicating lens function. The method can collimate a single-mode fiber, but does not have the function of an orthogonal biaxial aspheric fiber microlens.
Patent CN201210011571.6 discloses a single mode fiber connector with large mode area and a manufacturing method thereof, which is to perform thermal diffusion of core doping elements on a step multimode fiber to form a graded index lens with a refractive index decreasing outward in the radial direction, and is mainly used for the connection of the single mode fiber with large mode area, and does not have the function of an orthogonal biaxial aspheric fiber microlens.
Patent CN201721647567.3 discloses a laser fiber collimation focusing lens, which is characterized in that an optical fiber is connected to one end of a glass tube, and the other end is connected with a lens. Since the light beam is collimated by using the microlens, the case of inserting connection or the like cannot be applied, the range of use is limited, and the manufacturing is difficult.
Patent US4269648A discloses a method of mounting a microsphere coupling lens onto an optical fiber, where the microsphere coupling lens can be mounted onto the end of the optical fiber using an adhesive. A method for manufacturing a microlens at an optical fiber end is disclosed, but the method is complex in manufacturing process and does not have the function of an orthogonal biaxial aspheric optical fiber microlens.
Patent US7013678B2 discloses a method for manufacturing a graded index fiber lens, which is an important component in an optical fiber communication system and can be used as a lens, but the graded index fiber lens does not have the function of an orthogonal biaxial aspheric fiber micro lens, and the method has complicated process and high production cost.
Patent US7228033B2 discloses an optical waveguide lens and method of making the same by fusion splicing a uniform glass lens blank to the distal end of an optical fiber, heating and stretching the lens blank to separate it into two segments, and attaching the segments to the optical fiber defining a tapered end, and then heating the lens blank above its softening point to form a spherical lens. The optical waveguide lens can be used for collimating or focusing light beams, but the lens manufactured by the method does not have the function of an orthorhombic biaxial aspheric optical fiber micro lens.
The invention discloses an orthogonal biaxial aspheric optical fiber micro lens, which can be used for preparing a fiber integrated micro lens and can be widely applied to the fields of miniature endoscopes, cell biological optical fiber imaging systems, optical fiber optical tweezers systems, miniature unmanned aerial vehicles and the like of the orthogonal biaxial aspheric optical fiber micro lens based on the fiber integration. The method adopts a thermal diffusion technology to carry out thermal diffusion treatment on a finely designed elliptical core optical fiber in a constant temperature field, forms a non-circumferential symmetric refractive index gradient region with quasi-Gaussian distribution in the thermal diffusion region, and cuts the elliptical core optical fiber subjected to thermal diffusion in a fixed length manner to prepare the orthogonal biaxial aspheric optical fiber micro-lenses with different sizes. Compared with the prior art, the optical fiber micro lens has the advantages that the micro lens can be integrated on the optical fiber due to the adoption of the thermal diffusion technology and the finely designed elliptical core optical fiber, the function of the fiber-integrated aspheric lens can be realized on the optical fiber, and the fiber-integrated orthogonal biaxial aspheric optical fiber micro lens can be prepared in batches at low cost and high efficiency.
Disclosure of the invention
The invention aims to provide an orthogonal biaxial aspheric optical fiber micro lens which is simple to manufacture, low in cost and capable of being produced in batch.
The purpose of the invention is realized as follows:
the orthogonal biaxial aspheric optical fiber micro lens is prepared by thermal diffusion of an elliptical core optical fiber. The orthogonal biaxial aspheric optical fiber micro lens is prepared by thermal diffusion in a constant temperature field, and after the elliptical core dopant of the finely designed elliptical core optical fiber is diffused, the refractive index distribution is changed into non-circumferential symmetric quasi-Gaussian distribution which can be equivalent to a micro lens.
Thermal diffusion techniques are commonly used for expansion of the fundamental mode field, which enables the dopant profile in the fiber to be graded into a stable quasi-gaussian profile. The method comprises the steps of putting a finely designed elliptical core optical fiber into a constant temperature field for heating, gradually changing the distribution of dopants in the elliptical core into stable non-circumferentially symmetrical quasi-Gaussian distribution, and keeping the normalized frequency of the optical fiber unchanged in the heating process. The non-circular symmetrical quasi-Gaussian distribution of the dopant gradually changes the refractive index distribution of the elliptical core fiber into the non-circular symmetrical quasi-Gaussian distribution, and the light beam is bent towards a region with higher refractive index in the propagation process, so that the elliptical core fiber after heat diffusion has the function of an aspheric micro lens.
During thermal diffusion, the local doping concentration C can be expressed as:
d in formula (1) is the dopant diffusion coefficient; t is the heating time. D depends mainly on the type of different dopants, the host material and the local heating temperature. In most cases, considering the diffusion of germanium in the core of an optical fiber, the heating temperature of the fiber is almost uniformly constant with respect to the radial position r on its axisymmetric geometry, and the diffusion coefficient D is assumed to be constant with respect to the radial position r. In practice, neglecting the diffusion of dopants in the axial direction, the simplified diffusion equation (1) in cylindrical coordinates is:
the doping concentration C of the dopant is a function of the radial distance r and the heating time t. The diffusion coefficient D is also affected by the heating temperature and is expressed as:
t (z) in the formula (3) represents the heating temperature in K, which is related to the longitudinal position of the optical fiber in the furnace; r-8.3145 (J/K/mol) is an ideal gas constant; parameter D0And Q can be obtained from experimental data. Consider the initial boundary conditions:
where a is a constant and represents the diameter of the optical fiber.
The dopant local doping concentration profile C can be expressed as:
in the formula (5), f (r) is an initial concentration distribution, and the concentration at the fiber boundary surface r ═ a is 0. J. the design is a square0Is a first class zero order Bessel function with a characteristic value alphanIs the root of it
J0(aαn)＝0 (6)
Assuming that the refractive index profile of the optical fiber over the thermal diffusion region is proportional to the dopant profile, the refractive index profile of the optical fiber after thermal diffusion can be expressed as:
n in formula (7)clAnd ncoThe refractive indices of the fiber cladding and the intermediate core, respectively. When the heating temperature field is 1600 ℃, the refractive index distribution of the elliptical core optical fiber changes along with the heating time t. The curves 21, 22 and 23 are refractive index distributions of the elliptical core optical fiber in the axial radial direction of the optical fiber a after being heated for 0h, 0.2h and 0.4h respectively (as shown in fig. 2 a); curves 24, 25, and 26 are refractive index distributions along the axial radial direction of the optical fiber b after heating the elliptical core optical fiber for 0h, 0.2h, and 0.4h, respectively (see fig. 2 c). After the thermal diffusion treatment of 0.4h, the refractive index profiles of the a-axis (as shown in FIG. 2b) and the b-axis (as shown in FIG. 2d) of the elliptical core fiber tend to be stable and quasi-Gaussian. The elliptical cores have the same thermal diffusion coefficient in the a-axis and the b-axis, but have different diameters, so that the refractive index distribution is different after thermal diffusion.
Graded index lenses have been widely used in optical components and devices for collimation, focusing and coupling. A graded index lens refers to a lens in which the refractive index varies continuously in the axial, radial, or spherical directions. For an orthogonal biaxial aspheric fiber microlens with a radially graded index of refraction, the central index of refraction of the fiber is highest and decreases as the radial distance from the central axis increases.
The cross-sectional refractive index of the prepared fiber-integrated orthogonal biaxial aspheric optical fiber microlens after the elliptical core optical fiber is subjected to thermal diffusion for 0.4h is shown in fig. 3. FIG. 4 is a three-dimensional representation of the cross-sectional refractive indices of a fiber-integrated orthogonal biaxial aspheric fiber microlens. As can be seen from the figure, the refractive index profile of the orthorhombic biaxial aspheric fiber microlens is elliptical, i.e., a quasi-gaussian profile with non-circumferential symmetry, the central refractive index is the highest and decreases as the radial distance from the central axis increases.
When the fiber-integrated orthogonal biaxial aspheric optical fiber micro lens is prepared, the elliptical core optical fiber can be finely designed, including the design of the geometric dimension, the dopant type, the numerical aperture and the like of the elliptical core.
The invention is prepared by thermal diffusion in a constant temperature field when preparing the fiber integrated orthogonal biaxial aspheric optical fiber micro lens. The temperature of the constant temperature field is above 1000 ℃. Elliptical core fibers with different elliptical core dopants have different thermal diffusivity.
When the fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens is prepared, after the fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens is heated and diffused in a constant temperature field for a certain time, the elliptical core optical fiber subjected to thermal diffusion is cut in a fixed length, and then the orthogonal biaxial aspheric optical fiber micro-lens with different sizes can be prepared.
The invention discloses a method for preparing a fiber-integrated orthogonal biaxial aspheric optical fiber micro lens, which is characterized by comprising the following steps of:
the first step is to carry out fine design on the elliptical core optical fiber, including the design on the geometric dimension, the dopant species, the numerical aperture and the like of the elliptical core.
And secondly, performing thermal diffusion treatment on the elliptical core optical fiber, placing the elliptical core optical fiber in a constant temperature field for thermal diffusion treatment, and after heating for a certain time, gradually changing the refractive index distribution of the elliptical core optical fiber into stable quasi-Gaussian distribution which is not circularly symmetrical.
And thirdly, cutting the elliptical core optical fiber, and cutting the elliptical core optical fiber subjected to thermal diffusion in a fixed length manner to prepare the orthogonal biaxial aspheric optical fiber micro-lenses with different sizes.
When the fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens is prepared, after a certain period of thermal diffusion treatment, the refractive index distribution of the elliptical core optical fiber tends to stable non-circumferentially symmetrical quasi-Gaussian distribution, the central refractive index of the optical fiber is highest, and the central refractive index of the optical fiber is reduced along with the increase of the radial distance from the central axis. After the elliptical core optical fiber is subjected to thermal diffusion treatment, the dopant forms smooth non-circumferentially symmetrical quasi-Gaussian distribution in a thermal diffusion processing area. The distribution of the dopant is non-circumferential symmetric quasi-Gaussian distribution, the refractive index distribution of the elliptical core optical fiber is also non-circumferential symmetric quasi-Gaussian distribution, and the elliptical core optical fiber is bent towards a region with higher refractive index in the process of light beam propagation, so that the elliptical core optical fiber after thermal diffusion has the function of a micro lens.
As shown in fig. 3, the cross-sectional refractive index profile of the fiber-integrated orthogonal biaxial aspheric optical fiber microlens is elliptical, i.e., a quasi-gaussian profile that is not circumferentially symmetrical, and the central refractive index of the optical fiber is the highest and decreases as the radial distance from the central axis increases. When the incident light beam passes through the micro lens, the central and edge light rays are gradually bent towards the area with high refractive index, and the capability of bending the light rays by the a axis and the b axis is different, which is equivalent to an aspheric micro lens. Therefore, after the optical fiber is transmitted in the orthogonal biaxial aspheric optical fiber micro lens for a certain distance, the light beam can become an elliptic optical field distribution.
The fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens prepared by the invention can realize the function of shaping light beams, so that Gaussian light beams and the like are shaped into elliptical light field distribution. The fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens is cut in a fixed length, so that orthogonal biaxial aspheric optical fiber micro-lenses with different sizes can be prepared, and the function of beam shaping of different requirements is realized.
When the elliptical core optical fiber is finely designed, the dopant of the elliptical core can be one or more different doped dopants according to the requirement. When the elliptic core optical fiber is used for preparing the orthogonal biaxial aspheric optical fiber micro lens, the orthogonal biaxial aspheric optical fiber micro lens with larger mode field diameter can be prepared by designing larger elliptic core diameter or increasing heating time and heating temperature. One or more doped different dopants are used, and the implementation of the beam shaping function of the orthogonal biaxial aspheric optical fiber micro lens is not influenced.
The fiber-integrated orthogonal biaxial aspheric optical fiber micro lens provided by the invention is prepared by thermal diffusion of an elliptical core optical fiber. Compared with the prior art, the optical fiber micro lens has the advantages that the micro lens can be integrated on the optical fiber due to the adoption of the thermal diffusion technology and the finely designed elliptical core optical fiber, the function of the fiber-integrated aspheric lens can be realized on the optical fiber, and the fiber-integrated orthogonal biaxial aspheric optical fiber micro lens can be prepared in batches at low cost and high efficiency.
(IV) description of the drawings
FIG. 1 is a schematic representation of the refractive index profile of a fiber-integrated orthogonal biaxial aspheric optical fiber microlens before and after thermal diffusion fabrication.
Fig. 2a is a graph showing the change of the refractive index profile along the a-axis of an elliptical core optical fiber in a temperature field of 1600 c with the change of the heating time t, fig. 2b is a graph showing the refractive index profile along the a-axis of the elliptical core optical fiber after being heated for 0.4h, fig. 2c is a graph showing the change of the refractive index profile along the b-axis of the elliptical core optical fiber in a temperature field of 1600 c with the change of the heating time t, and fig. 2d is a graph showing the refractive index profile along the b-axis of the elliptical core optical fiber after being heated for 0.4 h.
FIG. 3 is a cross-sectional refractive index profile of an elliptical core fiber heated for 0.4 h.
FIG. 4 is a three-dimensional representation of the cross-sectional refractive index profile of an elliptical core fiber after heating for 0.4 h.
FIG. 5 is a schematic cross-sectional view of an elliptical core optical fiber according to an embodiment. 51 is the cladding of the elliptical core fiber, and 52 is the elliptical core of the elliptical core fiber.
FIG. 6 is a schematic structural diagram of a single-mode fiber + orthogonal biaxial aspheric fiber microlens in an embodiment. 61 is a single mode fiber and 62 is a fiber-integrated orthogonal biaxial aspheric fiber microlens made from an elliptical core fiber.
Fig. 7a is a refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the a-axis direction in the embodiment, fig. 7b is a three-dimensional display of the refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the a-axis direction in the embodiment, fig. 7c is a refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the b-axis direction in the embodiment, and fig. 7d is a three-dimensional display of the refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the b-axis direction in the embodiment.
Fig. 8a is a light field distribution of a fiber end outgoing light field of a single-mode fiber in an embodiment, fig. 8b is a light field distribution of a fiber end outgoing light field of a single-mode fiber + orthogonal biaxial aspheric fiber microlens in an a-axis direction in an embodiment, fig. 8c is a light field distribution of a fiber end outgoing light field of a single-mode fiber + orthogonal biaxial aspheric fiber microlens in a b-axis direction in an embodiment, fig. 8d is a light intensity distribution of a fiber end outgoing light field of a single-mode fiber in an embodiment, fig. 8e is a light intensity distribution of a fiber end outgoing light field of a single-mode fiber + orthogonal biaxial aspheric fiber microlens in an a-axis direction in an embodiment, and fig. 8f is a light intensity distribution of a fiber end outgoing light field of a single-mode fiber + orthogonal biaxial aspheric fiber microlens in a b-axis direction in an embodiment.
FIGS. 9 a-g are the optical field distributions of the section when the light beam propagates in the single mode fiber + orthogonal biaxial aspheric fiber microlens of the embodiment by 0 μm, 80 μm, 180 μm, 280 μm, 380 μm, 480 μm, and 580 μm, respectively.
(V) detailed description of the preferred embodiments
The invention is further illustrated below with reference to specific examples.
Example 1:
the cross-sectional view of the oval core fiber of this embodiment is shown in FIG. 5. Reference numeral 51 denotes a cladding of the elliptical core fiber, and 52 denotes an elliptical core of the elliptical core fiber.
The preparation steps of the fiber-integrated orthogonal biaxial aspheric optical fiber microlens of the embodiment are as follows:
the first step is to carry out fine design on the elliptical core optical fiber, including the design on the geometric dimension, the dopant species, the numerical aperture and the like of the elliptical core. The parameters of the elliptic core fiber finely designed in this example are that the cladding radius is 62.5 μm, the a-axis radius of the elliptic core is 17.5 μm, the b-axis radius is 10 μm, and the numerical aperture is 0.14. The dopant species of the oval core fiber is germanium.
And secondly, carrying out thermal diffusion treatment on the elliptical core optical fiber. And (3) putting a section of the elliptical core optical fiber in a constant temperature field for thermal diffusion treatment, wherein the temperature of the constant temperature field is 1600 ℃, and after heating for 0.4h, the refractive index distribution of the elliptical core optical fiber is gradually changed into stable non-circumferentially symmetrical quasi-Gaussian distribution.
And thirdly, cutting the elliptical core optical fiber, and cutting the elliptical core optical fiber subjected to thermal diffusion in a fixed length manner to prepare the orthogonal biaxial aspheric optical fiber micro-lenses with different sizes.
Firstly, a section of single-mode fiber is taken, the elliptical core fiber after thermal diffusion is welded with the single-mode fiber, and the elliptical core fiber after thermal diffusion is cut at a fixed length to be used as an orthogonal biaxial aspheric fiber micro-lens integrated with the fiber, so that a structure of the single-mode fiber and the orthogonal biaxial aspheric fiber micro-lens is formed, as shown in fig. 6. 61 is a single mode optical fiber; the cut oval core fiber 62 is a cut in length and heat-diffused oval core fiber, and is soldered as a microlens to the end of the single mode fiber 61.
A finite element method is used for establishing a model for the thermal diffusion treatment process of the optical fiber, and the change of the refractive index distribution after the thermal diffusion treatment is simulated. As shown in fig. 7a, the refractive index profile of the single mode fiber + orthogonal biaxial aspheric fiber microlens along the a-axis direction, and fig. 7c is the refractive index profile of the single mode fiber + orthogonal biaxial aspheric fiber microlens along the b-axis direction. In the established simulation model, the length of the single-mode fiber 61 is 5 μm, the numerical aperture is 0.14, the diameter of the fiber core is 9 μm, and the diameter of the cladding is 125 μm; the length of the fiber-integrated orthogonal biaxial aspheric fiber microlens 62 is 380 μm. FIG. 7b is a three-dimensional display of the refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the a-axis direction in the example, and FIG. 7d is a three-dimensional display of the refractive index profile of the single-mode fiber + orthogonal biaxial aspheric fiber microlens in the b-axis direction in the example.
The fiber-integrated orthogonal biaxial aspheric fiber microlens 62 has a smoothly graded index profile transition with an elliptical, i.e., stable, non-circumferentially symmetric, quasi-gaussian profile with a highest central index of refraction that decreases with increasing radial distance from the central axis.
In the embodiment, the refractive index distribution of the orthogonal biaxial aspheric optical fiber micro lens is elliptical, and modeling simulation is performed on tangent planes passing through the center line along the a axis and the b axis of the orthogonal biaxial aspheric optical fiber micro lens respectively. And (3) simulating the emergent light field of the single-mode fiber and the orthogonal biaxial aspheric fiber microlens by using a finite element method. In the established simulation model of the single mode optical fiber 61, the length of the single mode optical fiber 61 is 20 μm, and the length of the vacuum 63 is 200 μm. In the established simulation model of the single-mode fiber and the orthogonal biaxial aspheric fiber microlens, the length of the single-mode fiber 61 is 5 μm, the length of the fiber-integrated orthogonal biaxial aspheric fiber microlens 62 is 380 μm, and the length of the vacuum 63 is 200 μm. The simulation results are shown in fig. 8. Fig. 8a shows the light field distribution of the fiber end outgoing light of the single-mode fiber 61, fig. 8b shows the light field distribution of the fiber end outgoing light of the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 along the a-axis direction, fig. 8c shows the light field distribution of the fiber end outgoing light of the single-mode fiber + orthogonal biaxial aspheric fiber microlens along the b-axis direction, fig. 8d shows the light intensity distribution of the fiber end outgoing light field of the single-mode fiber 61, fig. 8e shows the light intensity distribution of the fiber end outgoing light field of the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 along the a-axis direction, and fig. 8f shows the light intensity distribution of the fiber end outgoing light field of the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 along the b-axis direction.
Comparing fig. 8a, 8b and 8c, the optical field distributions of the single-mode fiber 61, the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 along the a-axis direction and the fiber end outgoing of the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 along the b-axis direction are shown respectively. When the light beam propagates through the fiber-integrated orthogonal biaxial aspheric surface fiber microlens 62, the light rays in the a-axis direction and the b-axis direction are gradually bent toward the region with high refractive index, that is, the divergence angle of the outgoing light beam in the single mode fiber 61+ orthogonal biaxial aspheric surface fiber microlens 62 is smaller than that of the outgoing light beam in the single mode fiber 61. But the refractive index is higher along the b-axis direction, the bending power to the light is stronger along the b-axis direction, the beam divergence is smaller along the b-axis direction than along the a-axis direction, and the orthogonal biaxial aspheric fiber microlens 62 is equivalent to an aspheric microlens. Therefore, after the light beam is transmitted for a certain distance in the orthogonal biaxial aspheric fiber microlens 62, the light beam becomes an elliptical light field distribution. Compared with the light field distribution emitted from the fiber ends of the single-mode fiber 61 and the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62, the orthogonal biaxial aspheric fiber microlens 62 provided by the invention has the function of beam shaping.
Comparing fig. 8d, 8e and 8f, the light intensity distributions of the fiber end emergent light fields of the single mode fiber 61, the single mode fiber 61+ the orthogonal biaxial aspheric fiber microlens 62 along the a-axis direction and the single mode fiber 61+ the orthogonal biaxial aspheric fiber microlens 62 along the b-axis direction are shown respectively. The light intensity distribution of the light field emitted from the optical fiber end is 1/2e of the maximum value of the light field distribution energy when the light beam is emitted. In contrast, when the light beam propagates through the fiber-integrated orthogonal biaxial aspheric optical fiber microlens 62, the light rays along the a-axis direction and the b-axis direction are gradually bent to the region with high refractive index, that is, the energy of the light field of the emergent light beam in the single-mode fiber 61+ orthogonal biaxial aspheric optical fiber microlens 62 is concentrated and the propagation distance is farther than the energy of the light field of the emergent light beam in the single-mode fiber 61. But the refractive index is higher along the b-axis direction, the bending capability to the light ray along the b-axis direction is stronger, so the energy of the light field of the light beam along the b-axis direction is more concentrated than along the a-axis direction, and the light beam stably propagates in the vacuum 63. The orthogonal biaxial aspherical fiber microlens 62 according to the present invention has a function of shaping and collimating a light beam.
A simulation model is established by using a light beam propagation method, and FIGS. 9a to g are respectively the light field distribution of the tangent plane when the light beam propagates 0 μm, 80 μm, 180 μm, 280 μm, 380 μm, 480 μm and 580 μm in the single-mode fiber 61+ orthogonal biaxial aspheric fiber microlens 62 in the embodiment. When the light beam propagates in the axial direction, the light beam diameter is gradually increased along the a axis and the b axis by the circumferentially symmetric gaussian distribution light field in the single-mode fiber 61, and the light beam diameter of the b axis is smaller than that of the a axis. Thus, when propagating in the fiber-integrated orthogonal biaxial aspherical fiber microlens 62, the circumferentially symmetric gaussian distributed beam gradually changes into a non-circumferentially symmetric elliptically distributed beam and propagates stably in the vacuum 63.
The fiber-integrated orthogonal biaxial aspheric optical fiber micro lens provided by the embodiment of the invention can integrate the micro lens on an optical fiber and can realize the function of the fiber-integrated aspheric micro lens on the optical fiber. Compared with the prior art, due to the adoption of the thermal diffusion technology and the finely designed elliptical core optical fiber, the fiber-integrated orthogonal biaxial aspheric optical fiber micro-lens can be prepared in batches at low cost and high efficiency.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto. Various modifications and alterations of this invention will occur to those skilled in the art in view of the spirit and scope of this invention and are intended to be encompassed by the following claims.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010389630.8A CN111624702B (en) | 2020-05-10 | 2020-05-10 | Orthogonal double-shaft aspheric optical fiber micro lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010389630.8A CN111624702B (en) | 2020-05-10 | 2020-05-10 | Orthogonal double-shaft aspheric optical fiber micro lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111624702A CN111624702A (en) | 2020-09-04 |
| CN111624702B true CN111624702B (en) | 2022-05-17 |
Family
ID=72269904
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010389630.8A Active CN111624702B (en) | 2020-05-10 | 2020-05-10 | Orthogonal double-shaft aspheric optical fiber micro lens |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111624702B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5301252A (en) * | 1991-09-26 | 1994-04-05 | The Furukawa Electric Company, Ltd. | Mode field conversion fiber component |
| JPH0882718A (en) * | 1994-09-14 | 1996-03-26 | Furukawa Electric Co Ltd:The | Method for making core of elliptic core optical fiber completely round and production of optical fiber by using this method |
| CN110446957A (en) * | 2017-03-22 | 2019-11-12 | 株式会社藤仓 | Polarization maintaining optical fibre, optical device, the base material of polarization maintaining optical fibre and manufacturing method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5256851A (en) * | 1992-02-28 | 1993-10-26 | At&T Bell Laboratories | Microlenses for coupling optical fibers to elliptical light beams |
| WO2002075396A2 (en) * | 2001-03-16 | 2002-09-26 | Cidra Corporation | Thermally diffused multi-core waveguide |
| US7481588B2 (en) * | 2006-11-21 | 2009-01-27 | Kvh Industries, Inc. | Optical fiber composite, devices, and methods of making same |
-
2020
- 2020-05-10 CN CN202010389630.8A patent/CN111624702B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5301252A (en) * | 1991-09-26 | 1994-04-05 | The Furukawa Electric Company, Ltd. | Mode field conversion fiber component |
| JPH0882718A (en) * | 1994-09-14 | 1996-03-26 | Furukawa Electric Co Ltd:The | Method for making core of elliptic core optical fiber completely round and production of optical fiber by using this method |
| CN110446957A (en) * | 2017-03-22 | 2019-11-12 | 株式会社藤仓 | Polarization maintaining optical fibre, optical device, the base material of polarization maintaining optical fibre and manufacturing method |
Non-Patent Citations (1)
| Title |
|---|
| Spatial effect of conical angle on optical-thermal distribution for circumferential photocoagulation;VAN GIA TRUONG.et.al;《Biomedical Optics Express》;20170901;第8卷(第12期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111624702A (en) | 2020-09-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6963682B2 (en) | Beam altering fiber lens device and method of manufacture | |
| JP3121614B2 (en) | Method of manufacturing cylindrical microlenses of selected shape and products obtained thereby | |
| US5081639A (en) | Laser diode assembly including a cylindrical lens | |
| US5155631A (en) | Method for fabrication of cylindrical microlenses of selected shape | |
| EP3218750B1 (en) | Adiabatic optical coupling systems | |
| CN111650688B (en) | An optical fiber micro-combination lens | |
| EP1664868A2 (en) | Fiber lens with multimode pigtail | |
| CN106291821A (en) | A kind of hollow-core photonic crystal fiber bonder | |
| WO2017195691A1 (en) | Optical lens and manufacturing method for optical lens | |
| KR100651560B1 (en) | Planar lightwave circuit and its manufacturing method | |
| Hoque et al. | Design and fabrication of a biconvex aspherical microlens for maximizing fiber coupling efficiency with an ultraviolet laser diode | |
| CN111624702B (en) | Orthogonal double-shaft aspheric optical fiber micro lens | |
| US20030165290A1 (en) | Optical signal altering lensed apparatus and method of manufacture | |
| CN111650690A (en) | A micro-collimator based on double-clad fiber | |
| CN111624700A (en) | Fiber-integrated optical fiber concave lens and preparation method thereof | |
| CN111650689B (en) | Fiber integrated micro lens set | |
| CN102109645B (en) | Coupling device of semiconductor strip laser diode and single-mode fiber | |
| CN111624703B (en) | Fiber integrated Fourier transform micro optical system | |
| CN111650692A (en) | A multi-core fiber beam splitter based on high refractive index matching liquid | |
| WO1992006521A1 (en) | Laser diode assembly including a cylindrical lens | |
| JPH0843678A (en) | Optical fiber lens and manufacturing method thereof | |
| Ross et al. | Microlenses for astrophotonic instruments manufactured by ultrafast-laser assisted etching | |
| US20240075699A1 (en) | Process for manufacturing by moulding an optical component, optical fibre comprising said optical component and system for manufacturing by moulding said optical component | |
| JPS6160595B2 (en) | ||
| CN116736439A (en) | Manufacturing method of three-dimensional directional coupler based on femtosecond laser direct writing technology |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20200904 Assignee: Jianuo (Tianjin) Technology Development Co.,Ltd. Assignor: GUILIN University OF ELECTRONIC TECHNOLOGY Contract record no.: X2023980045809 Denomination of invention: A Kind of Orthogonal Biaxial Aspheric Fiber Microlens Granted publication date: 20220517 License type: Common License Record date: 20231107 |
|
| EE01 | Entry into force of recordation of patent licensing contract | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20200904 Assignee: Ningbo Yifei Technology Co.,Ltd. Assignor: GUILIN University OF ELECTRONIC TECHNOLOGY Contract record no.: X2024980021661 Denomination of invention: An orthogonal biaxial non spherical fiber optic microlens Granted publication date: 20220517 License type: Common License Record date: 20241101 |