Method of manufacturing an optical fiber preform
By using laser-assisted etching technology to define the core structure of optical fiber preforms in high-purity fused silica substrates, the problems of time-consuming and costly manufacturing of microstructured optical fibers in existing technologies have been solved, achieving efficient and precise manufacturing of optical fiber preforms and expanding their application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HERIOT WATT UNIV
- Filing Date
- 2021-03-10
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies for manufacturing microstructured optical fibers suffer from problems such as being time-consuming, labor-intensive, costly, and difficult to achieve multiple core designs. Traditional 3D printing methods also result in poor material smoothness, leading to low glass quality.
By employing subtractive materials techniques (such as laser-assisted etching), the core structure is directly defined in a high-purity fused silica substrate. The transverse segments of the optical fiber preform are then formed by laser writing and chemical etching, achieving automation and precise control.
It enables a fast, accurate, and repeatable fiber optic preform manufacturing process, reducing costs and producing high-quality hollow-core optical fibers suitable for applications such as high-speed, low-latency data communication, laser manufacturing, sensing, telecommunications, spectroscopy, and high-power laser transmission.
Smart Images
Figure CN115279709B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a method for manufacturing optical fiber preforms and a method for assembling optical components such as optical fiber preforms. Background Technology
[0002] Traditional optical fibers are made from solid glass preforms, whose doped and undoped regions form the core and cladding regions of the fiber.
[0003] Microstructured optical fibers (MOFs) are typically fabricated from preforms made of a bundle of rods and capillaries of one or more materials, but the physical arrangement of these microstructured fibers results in the final fiber including a large number of air regions. An example of such a fiber is a hollow-core fiber, in which light is guided in regions of the fiber that are not glass-like. MOFs include photonic crystal fibers, hollow-core fibers, negative curvature fibers, and antiresonant fibers; some of these terms are often used interchangeably.
[0004] Such fibers are attracting significant attention from a wide range of applications, including telecommunications, fiber lasers and high-power laser transmission in advanced manufacturing, high-power transmission, nonlinear photonics, and spectroscopy. In some cases, MOFs can exhibit several advantages over conventional optical fibers, including lower propagation loss, a higher damage threshold, and a wider spectral bandwidth.
[0005] Currently, MOFs are manufactured using labor-intensive "stacked drawing" techniques, in which glass capillaries or rods are precisely stacked side-by-side to form a preform, which is then heated and drawn to form fibers. Figure 1 shows an example of a stacked MOF preform 100, which comprises a hexagonal array of tightly but unevenly packed glass rods 102. In practice, the preform can be any size, ranging from about 10 cm long and 10 mm wide to several meters long and tens of centimeters wide (e.g., about 50 cm long and 10 mm wide). Figure 2 shows an apparatus 200 for drawing such a preform 100 from a relatively short and wide structure into longer and thinner fibers 202. The preform 100 is held at its top by a chuck 204, and its lower end is positioned within a heating chamber or furnace 206. As the lower end of the preform 100 melts, the fine fibers 202 are drawn downwards and wound onto a spool 208.
[0006] The "stacked drawing" technique is very time-consuming, labor-intensive, and requires highly skilled personnel, making the manufacturing cost of such MOFs expensive. High repeatability is also a challenge. Furthermore, fibers can only be produced in a limited number of preform patterns, thus many MOF core designs desired by applications and industries cannot be manufactured.
[0007] However, there is currently great interest in developing hollow core pure fused silica fibers for applications including low-latency fiber links in data centers and power transmission fibers for high peak power laser transmission. Therefore, there is a desire to reduce costs so that MOFs can be more easily developed and utilized.
[0008] Some work has been done using 3D printing technology to fabricate glass preforms for optical fiber manufacturing, such as the glass preforms described in the following document: “Silica optical fiber drawn from 3D printed preforms”, Opt. Lett. 44, 5358-5361 (2019); Yushi Chu et al. This manufacturing process is based on ultraviolet (UV) curing of quartz nanoparticles suspended in resin. However, the material finish is generally poor, and therefore the core characteristics are not well defined. Consequently, the resulting glass is of low quality due to defects and impurities.
[0009] Therefore, the purpose of this disclosure is to provide a method for manufacturing optical fiber preforms to solve one or more of the problems mentioned above, or at least to provide a useful alternative. Summary of the Invention
[0010] Generally, this disclosure proposes to overcome the aforementioned problems by using subtractive manufacturing techniques (such as laser-assisted etching) to directly define the core structure in a high-purity fused silica substrate to fabricate optical fiber preforms. This enables a highly automated process, thereby facilitating complete control over the core structure.
[0011] According to one aspect of this disclosure, a method for manufacturing an optical fiber preform is provided, the method comprising:
[0012] A subtractive manufacturing process is used on the optical monolithic material to define at least a lateral segment of the fiber preform within the optical monolithic material; and
[0013] The transverse segment includes at least two regions with different refractive indices.
[0014] Therefore, embodiments of this disclosure provide a method for manufacturing an optical fiber preform that uses a subtractive process to define at least lateral segments of the preform from a monolithic optical material. This enables a potentially faster, more precise, and repeatable process for manufacturing the optical fiber preform, which can then be drawn using conventional techniques to achieve low-cost (potentially, hollow-core) optical fibers. Advantageously, this method allows for the removal of holes and regions of arbitrary shapes from each lateral segment, enabling fiber manufacturing that was not possible using prior art techniques.
[0015] Subtractive manufacturing processes can include laser-assisted etching (LAE), which involves laser-writing a structure within a monolithic optical material and then chemically etching that structure to obtain lateral segments. In other words, short (e.g., picosecond, femtosecond, or nanosecond) laser pulses capable of penetrating several millimeters into the material can be used to write the monolithic optical material in three dimensions, followed by selective chemical etching to remove the etched (i.e., laser-written) material. The result is a preform of the optical material forming lateral segments or slices of the preform. This laser-based fabrication (sometimes referred to as laser printing or laser writing) can be performed using ultrafast pulsed lasers. Advantageously, in some embodiments, preforms up to 200 mm long can be fabricated in one or more days, whereas conventional techniques require several weeks. Therefore, embodiments of the present invention can translate the commercial potential and applications of such microstructured optical fibers.
[0016] The lateral segment may be defined by a laser beam oriented in a plane perpendicular to the lateral segment. In some embodiments, the lateral segment may be defined by a laser beam oriented in a plane parallel to the lateral segment.
[0017] The optical monolith (i.e., substrate, wafer, or blank) can include any suitable material from which the optical fiber is produced. In particular, the optical monolith can include high-quality (ultra-pure) fused silica glass for the manufacture of high-quality optical fibers.
[0018] The transverse segments may include structured cores and / or hollow cores.
[0019] The method may include:
[0020] The optical fiber preform is defined using a subtractive manufacturing process, defining at least two lateral segments; and
[0021] At least two lateral segments are stacked to form a stacked fiber optic preform.
[0022] Although the preform can be formed integrally using embodiments of the present invention, greater precision can be achieved by manufacturing multiple discrete lateral segments (i.e., slabs) and then stacking them end-to-end to form an optical fiber preform.
[0023] One might assume that the preforms manufactured using the proposed technology would be affected by the discrete properties of the laser-written slab from which the preforms are constructed. However, this is not the case, as the subsequent fiber drawing process involves heating the preform to >1500 degrees Celsius, during which the boundary regions between the transverse segments completely melt and disappear due to surface tension.
[0024] The method may further include connecting at least two lateral segments to form a stacked fiber optic preform.
[0025] This connection determines the passive alignment of at least two lateral segments. This helps ensure that the desired longitudinal optical path through the preform is achieved with minimal (or no) manual input or skill required.
[0026] The connection can be achieved using at least one interconnect feature defined in at least one of at least two lateral segments.
[0027] At least one interconnecting feature in at least one lateral segment can be configured to be directly or indirectly connected to another lateral segment.
[0028] At least one interconnecting feature can be configured to be connected using one or more of the following: pins, tenons, spherical parts, dovetail joints, threaded portions, rings, plug socket arrangements, and self-centering positioning elements.
[0029] The method may further include bonding at least two lateral segments in a stacked fiber preform.
[0030] The bonding may include one or more of the following: catalytic bonding; ultrafast laser bonding; optical contact bonding; or laser welding (e.g., CO2 laser welding).
[0031] Typically, each transverse segment of a particular preform will be identical. However, it is also possible to use the same process to create a preform whose pattern varies along its length, thereby producing a fiber core structure that varies along the fiber length.
[0032] Accordingly, optical fiber preforms can be manufactured with a core structure that varies longitudinally.
[0033] Optical fiber preforms can be formed from two or more transverse segments with different core structures.
[0034] According to a second aspect of this disclosure, a lateral segment of an optical fiber preform manufactured according to the first aspect is provided.
[0035] According to a third aspect of this disclosure, an optical fiber preform manufactured according to the first aspect is provided.
[0036] According to the fourth aspect of this disclosure, an optical fiber manufactured from the optical fiber preform of the third aspect is provided.
[0037] Optical fibers manufactured from preforms produced according to the first aspect of the invention can have a variety of applications, including high-speed, low-latency data communication, laser manufacturing, sensing, advanced telecommunications, spectroscopy, biomedical photonics, and high-power laser transmission.
[0038] According to the fifth aspect of this disclosure, a method for assembling optical components is provided, the method comprising:
[0039] The first interconnect feature in the first optical component is defined using a subtractive manufacturing process, or the first interconnect feature is defined for use with the first optical component.
[0040] Using a subtractive manufacturing process to define a second interconnect feature in a second optical component or to define a second interconnect feature used with the second optical component; and
[0041] The first component and the second component are connected together using a first interconnect feature and a second interconnect feature, such that the connection determines the passive alignment of the first component and the second component.
[0042] Embodiments of this aspect of the invention are advantageous because passive alignment of the two optical components can be guaranteed by providing interconnect features inscribed in each of these components or interconnect features used in conjunction with each of these components.
[0043] The first interconnect feature and the second interconnect feature can be configured for direct or indirect connections.
[0044] The first interconnecting feature and / or the second interconnecting feature may be configured to be connected using one or more of the following: pins, tenons, spherical parts, (sliding) dovetail joints, threaded portions, rings, plug socket arrangements, and self-centering (e.g., conical) positioning elements.
[0045] The fifth aspect of the method may further include bonding the first optical component and the second optical component together once the first optical component and the second optical component are coupled.
[0046] The bonding may include one or more of the following: catalytic bonding; ultrafast laser bonding; optical contact bonding; or laser welding (e.g., CO2 laser welding).
[0047] The method may further include manufacturing at least one of the first and second optical components using a subtractive manufacturing process.
[0048] At least one of the first and second optical components may include: an optical substrate; an image splitter (e.g., a Bowen image splitter); or at least a lateral segment of an optical fiber preform.
[0049] According to a sixth aspect of this disclosure, an optical device is provided, which includes optical components assembled according to a fifth aspect. Attached Figure Description
[0050] Some embodiments of this disclosure will now be described by way of example only, with reference to the accompanying drawings, in which:
[0051] Figure 1 shows an optical fiber preform according to the prior art;
[0052] Figure 2 shows an apparatus for drawing optical fibers from optical fiber preforms according to the prior art;
[0053] Figure 3 The apparatus for manufacturing optical fiber preforms according to this disclosure is shown;
[0054] Figures 4A, 4B, and 4C illustrate the use of Figure 3 Examples of optical components manufactured for equipment;
[0055] Figure 5 A shows a lateral segment of the optical fiber preform according to this disclosure;
[0056] Figure 5 B illustrates the alignment ring used in an embodiment of this disclosure;
[0057] Figure 5 C illustrates a stacked optical preform according to an embodiment of this disclosure, the stacked optical preform having recesses for receiving additional lateral segments;
[0058] Figure 5 D shows the relationship with Figure 5 C's stacked optical preforms are similar to stacked optical preforms, but with additional transverse sections threaded into the sockets.
[0059] Figure 5 E shows Figure 5 The other transverse sections in D and the transverse cross-sectional view of the uppermost alignment ring;
[0060] Figure 6 A shows a transverse section of an optical fiber preform according to an embodiment, including alignment holes;
[0061] Figure 6 B shows Figure 6 A transverse section, wherein the aligning tenon is inserted into the aligning hole;
[0062] Figure 7 Possible chemical bonds between lateral segments according to embodiments of this disclosure are illustrated;
[0063] Figure 8 This illustration shows two lateral sections using self-centering conical pins for passive alignment according to an embodiment of this disclosure; and
[0064] Figure 9A and Figure 9B Two lateral sections are shown using a sliding dovetail joint to achieve passive alignment according to an embodiment of this disclosure. Detailed Implementation
[0065] Generally, this disclosure provides a method for manufacturing optical fiber preforms and a method for assembling optical components (such as, but not limited to, the optical fiber preforms). This disclosure also provides the manufacture of small-scale glass preforms that can then be tapered on a fiber tapering rig.
[0066] In particular, Figure 3 An apparatus 300 for manufacturing an optical fiber preform 302 according to the proposed method is shown. The apparatus includes an ultrafast pulsed laser 302 configured for use in a subtractive laser-assisted etching process on an optical monolith 304 (which is in the form of a cubic fused silica slab). The laser 302 is configured to define at least a lateral segment 306 of the optical fiber preform by laser-writing a predetermined three-dimensional pattern in the optical monolith 304. As shown, the laser 302 is oriented to guide the laser beam in a direction A parallel to the plane of the lateral segment 306. In other embodiments, the laser 302 may be oriented to guide the laser beam in a direction B perpendicular to the plane of the lateral segment 306. After the desired pattern is laser-written in the optical monolith 304, the etched material is selectively removed using a wet chemical etching process, and then the lateral segment 306 is removed from the optical monolith 304. This technique, known as ultrafast laser-assisted etching (ULAE), enables the removal of quartz or other materials from a substrate in a three-dimensional manner with micron-level precision. Further details of the proposed technique can be found in CARoss, DGMacLachlan, D. Choudhury, and RRThomson, “Optimisation of ultrafast laser assisted etching in fused silica,” Opt. Express, 26(19), 24343 (2018), which is incorporated herein by reference.
[0067] The transverse segment 306 includes at least two regions with different refractive indices. In particular, as shown, the transverse segment 306 has a hollow core 308 and six hollow segments 310 that are radially spaced from and surround the hollow core 308.
[0068] Although the transverse section 306 is in Figure 3 While shown as a longer shape, in some embodiments, much shorter lateral segments are manufactured, which are then stacked, aligned, and bonded to form a fiber optic preform with high precision.
[0069] Figures 4A, 4B, and 4C illustrate the use of Figure 3 Examples of optical components manufactured using the equipment and methods described above are provided. Specifically, Figure 4A shows a star-shaped transverse section 400 with a hollow cylindrical core; Figure 4B shows a transverse section with four rhomboid cutouts 402; and Figure 4C shows a preform comprising cylindrical portions of varying lengths. It is noteworthy that the dimensions of each of these optical components are adapted to embodiments of the invention.
[0070] Figure 5 A to Figure 5 E demonstrates a method for assembling optical components similar to those described above to form optical preforms.
[0071] In particular, Figure 5 A shows a lateral segment 500 of an optical fiber preform according to this disclosure. The lateral segment 500 is in the form of a disc having a preform pattern 502, a hollow core 504 etched from the center of the disc, and upper and lower external threads 506 formed by laser-assisted etching of the outer circumference of the disc. Figure 5 B illustrates an alignment ring 510, which is laser-etched from the same material as the transverse sections 500, and the two transverse sections 500 can be partially threaded into the alignment ring. The alignment ring 510 includes an upper inner channel 512 for receiving an upper external thread 506 of the transverse sections 500 and a lower inner channel 514 for receiving a lower external thread 506 of the transverse sections 500.
[0072] Figure 5 C illustrates a stacked optical preform 520 according to an embodiment of this disclosure, the stacked optical preform having a recess to receive additional lateral segments 500. The stacked optical preform 520 includes a plurality of lateral segments 500 threadedly connected in a stacked configuration to a plurality of alignment rings 510 to form a solid preform without air gaps. Figure 5 D shows the relationship with Figure 5 The stacked optical preform 520 of C is similar to the stacked optical preform, but has an additional transverse section 500 threaded into the socket of the top alignment ring 512, such that the upper external thread 506 of the additional transverse section 500 protrudes above the alignment ring 512 and is threaded into another alignment ring 512, and so on. Figure 5 E shows a cross-sectional view of the transverse section 500 in the upper inner channel 512 of the alignment ring 510, wherein the lower inner channel 514 of the alignment ring 510 awaits the insertion of another transverse section 500.
[0073] Notably, each transverse segment 500 has two individual 360-degree threads 506, allowing the transverse segments 500 to be infinitely stacked and coupled or locked together using complementary alignment rings 510. The pitch of the threads 506 ensures that the individual transverse segments 500 contact each other within the alignment rings 510 after a full 360-degree rotation, and threaded end connectors (not shown) prevent over-tensioning, ensuring precise lateral alignment, longitudinal alignment, and rotational alignment. The threads 506 also provide compressive pressure between the transverse segments 500, which holds the preform 520 together, ready for drawing.
[0074] The exposed upper and lower flat surfaces of the transverse segments 500 are optically polished and remain substantially unchanged from the original optical monolith composed of raw quartz, which is laser-written to form individual transverse segments 500. Therefore, the optical contact between these surfaces means that no additional bonding is required. During drawing, any discontinuities in the structure at the interfaces between the transverse segments 500 (or between the transverse segments 500 and the alignment ring 510) are annealed and drawn out a significant distance, so that the individual transverse segments 500 (and the alignment ring 510) are no longer indistinguishable in the final fiber.
[0075] Figure 6 A illustrates another transverse segment 600 according to an embodiment, which is in the form of a disc having a preform pattern 602 and a hollow core 604 etched from the center of the disc. However, in this case, instead of external threads, three alignment holes 606 (equally spaced) are laser-etched into the edges of the transverse segment 600 and extend from the upper flat surface to the lower flat surface of the transverse segment 600. Figure 6 As shown in Figure B, alignment tenons 610 (e.g., pins) etched from the same material as the transverse segments 600 are partially inserted into each alignment hole 606, such that the protruding half is used to position and align the other transverse segments 600 placed on top, and so on. In some embodiments, the alignment tenons 610 may be longer than the thickness of the transverse segments 600, such that a single alignment tenon can extend through multiple alignment holes 606 in the multiple transverse segments 600 for assembly.
[0076] Although the alignment hole 606 is shown as extending fully through each transverse segment 600, in some embodiments, blind alignment holes may be provided to position the alignment tenon 610 at the middle position within each transverse segment 600.
[0077] However, in this case, separate alignment holes need to be etched on both the upper and lower surfaces of each transverse segment 600.
[0078] Alignment holes 606 and alignment tenons 610 are used to align the transverse section 600 laterally and rotationally. The advantage of this method is that it eliminates the need to manufacture complex screws or alignment rings, thus reducing manufacturing time. However, alignment tenons 610 must be placed in alignment holes 606 by hand or machine, which increases assembly time and may necessitate additional surface bonding.
[0079] Lateral segments made of quartz can be bonded together using any of several “direct bonding” techniques that do not rely on any exogenous substances (such as glue) that remain as impurities in the fiber after drawing. Here, direct bonding refers to any technique that results in the chemical fusion of silicate components, but it also extends to optical contact, in which two extremely flat surfaces are held together purely by intermolecular forces. Although optical contact may not immediately produce a permanent bond, the process of drawing the preform in a furnace causes interfacial mixing, which produces a permanent, indistinguishable bond. During optical contact, a small amount of isopropanol or the like can be dropped onto the surface of one of the parts to allow for a period of alignment before evaporation renders the parts immobile.
[0080] In cases where optical contact is insufficient, chemically activated direct bonding can be used. In the case of quartz, hydroxide-catalyzed bonding can be employed, such as the hydroxide-catalyzed bonding described in detail in the following documents: EJ Elliffe, J. Bogenstahl, A. Deshpande, J. Hough, C. Killow, S. Reid, D. Robertson, S. Rowan, H. Ward and G. Cagnoli, “Hydroxide-catalysis bonding for stable optical systems for space,” in Classical and Quantum Gravity, (2005), 22(10); and Anna-Maria A. van Veggel and Christian J. Killow, “Hydroxide-catalysis bonding for astronomical instruments,” Adv. Opt. Techn., 2014, 3(3): 293-307. These documents describe a process for chemically activating a surface by generating dangling silicon bonds that preferentially attach hydroxide molecules to the surfaces of paired surfaces. The process works as follows: an alkaline solution, such as potassium hydroxide, is placed on one surface, and then another surface is placed in contact with it. OH- ions etch the quartz surface, releasing silicate ions. The released ions lower the pH of the solution until dissociation occurs and siloxane polymer chains form. These chains form strong bonds between the surfaces and become ridged as water byproducts dehydrate.
[0081] Figure 7 This illustrates a possible chemical bond 702 between two bulk quartz components 700 (which may be lateral segments and / or alignment features) according to an embodiment of this disclosure.
[0082] Figure 8The illustration shows two transverse segments 800 with a structured core, passively aligned using two self-centering conical pins 802, according to an embodiment of this disclosure. These two self-centering conical pins are inserted into two corresponding conical recesses 804 in the edge of each surface of the transverse segments 800. The conical pins 802 are similar to the tenons described above, but have short cylindrical bodies. The conical ends of these cylindrical bodies are easily inserted and positioned within each transverse segment 800 due to their conical properties, thereby facilitating component guidance and alignment. This can therefore accelerate the assembly process of optical preforms and allow for automated assembly. Alternatively, micromachined fused silica spheres can be used instead of pins, as pin orientation is not required, further simplifying the assembly process.
[0083] like Figure 8 As shown, the two conical recesses 804 on the lower surface of each transverse segment 800 are offset by 90 degrees relative to the two conical recesses 804 on the upper surface of each transverse segment 800. This helps prevent any interference or overlap between the conical recesses 804 on the upper and lower surfaces and allows the depth of each conical recess 804 to be 50% of the thickness of the transverse segment 800 or greater for a secure connection and interlocking. Notably, due to the symmetrical properties of the structured core, offset of the alignment features is possible in this embodiment. This may not always be the case.
[0084] Figure 9A and Figure 9B Two transverse segments 900 are illustrated using a sliding dovetail joint for passive alignment according to an embodiment of this disclosure. Each transverse segment 900 includes a structured core and two dovetail channels 902 in its upper surface and two corresponding dovetail protrusions 904 in its lower surface. The dovetail protrusions 904 on the upper transverse segment 900 are configured to slide laterally into the dovetail channels 902 in the lower transverse segment 900 to join the two transverse segments 900 together in a predetermined alignment during prefabrication. In this case, the two transverse segments 900 can be directly bonded by optical contact or chemical bonding as described above. Additionally, the dovetail channels may be tapered, allowing the upper transverse segment to wedge into the lower transverse segment.
[0085] Generally, one aspect of the present invention relates to a method of assembling an optical component, the method comprising: defining a first interconnect feature in a first optical component or defining a first interconnect feature used with the first optical component using a subtractive process (e.g., laser-assisted etching); defining a second interconnect feature in a second optical component or defining a second interconnect feature used with the second optical component using a subtractive process (e.g., laser-assisted etching); and joining the first component and the second component together using the first interconnect feature and the second interconnect feature, such that the joining determines the passive alignment of the first component and the second component.
[0086] While most drawing involves the fabrication and alignment of lateral segments of optical preforms, it should be understood that aspects of the invention (such as those described above) are more broadly applicable to any optical component. For example, macroscale glass components (e.g., splitters or other components) can be fabricated by combining two or more separate components that can themselves be manufactured using subtractive processes (e.g., laser-assisted etching). Furthermore, aspects of the invention extend to the alignment of optical micro-components on glass “test boards” or optical substrates, including alignment and bonding features such as those described above, written with laser writing.
[0087] The various aspects of the present invention have many advantages over the prior art, such as producing more accurate and purer fiber optic preforms and generally ensuring easy alignment and connection of optical components.
[0088] Those skilled in the art will understand that positional terms such as “upper,” “lower,” “top,” and “side” in the foregoing description and appended claims are given with reference to conceptual illustrations (e.g., those shown in the accompanying drawings). These terms are used for ease of reference but are not intended to be restrictive. Therefore, these terms should be understood to refer to the orientation of an object as shown in the accompanying drawings.
[0089] Although this disclosure has been described with respect to preferred embodiments as set forth above, it should be understood that these embodiments are merely illustrative and the claims are not limited to those embodiments. Modifications and substitutions will be able to be made based on this disclosure by those skilled in the art, and such modifications and substitutions are considered to fall within the scope of the appended claims. Each feature disclosed or shown in this specification, whether alone or in any suitable combination with any other feature disclosed or shown herein, may be incorporated into any embodiment.
Claims
1. A method for manufacturing an optical fiber preform, the method comprising: A subtractive process is used on the optical monolith to define at least two transverse slices of the optical fiber preform within the optical monolith; and The at least two transverse slices are stacked end-to-end and joined to form a stacked fiber optic preform. Each of the at least two transverse slices comprises at least two regions with different refractive indices.
2. The method of claim 1, wherein, The subtractive material process includes laser-assisted etching.
3. The method of claim 2, comprising laser-writing a structure in the optical monolith and chemically etching the structure to obtain the transverse slice.
4. The method of any preceding claim, wherein, The subtractive manufacturing process includes removing holes and regions of arbitrary shapes from each transverse slice, such that the transverse slice includes a structured core and / or a hollow core.
5. The method of claim 1, wherein, The connection determines the passive alignment of the at least two lateral slices.
6. The method of claim 1 or 5, wherein, The connection is achieved using at least one interconnect feature defined in at least one of the at least two lateral slices.
7. The method of claim 6, wherein, The at least one interconnecting feature in the at least one lateral slice is configured to be directly or indirectly connected to another lateral slice.
8. The method of claim 6 or 7, wherein, The at least one interconnecting feature is configured to be connected using one or more of the following: pins, tenons, spherical parts, dovetail joints, threaded portions, rings, plug socket arrangements, and self-centering positioning elements.
9. The method according to any one of claims 1 to 8, further comprising bonding the at least two lateral slices in the stacked optical fiber preform.
10. The method of claim 9, wherein, The bonding includes one or more of the following: catalytic bonding; ultrafast laser bonding; optical contact bonding; or laser welding.
11. The method according to any of the preceding claims, wherein, The optical fiber preform is manufactured with a core structure that varies longitudinally.
12. The method according to claim 11, wherein, The optical fiber preform is formed from two or more transverse slices with different core structures.
13. A transverse slice of an optical fiber preform manufactured by the method according to any one of claims 1-12.
14. An optical fiber preform manufactured by the method according to any one of claims 1-12.