JP2007518140A - Optical fiber with lens chip and manufacturing method thereof - Google Patents

Abstract

  A method of manufacturing an optical fiber with a lens chip is provided. The method includes providing a light transmissive cylindrical fiber and etching a first end of the light transmissive cylindrical fiber to form a tip portion. When the tip portion is heated, a lens surface is formed on the heated tip portion. This optical fiber with a lens chip facilitates the optical position adjustment with another optical fiber and the coupling between the optical fiber and the optical device.

Description

  This application is a continuation-in-part of US application number 10 / 754,365 filed January 8, 2004, a continuation-in-part application of US application number 10 / 775,793, filed February 9, 2004, and 2004. No. 10 / 786,766, filed Feb. 24, all of which are by the same applicant and are incorporated herein by reference for all purposes.

  The present invention generally relates to an optical fiber forming process, and more particularly to a method of forming an optical fiber with a lens chip.

  Many applications require light wave propagation control similar to that in light sources such as planar waveguides, optical integrated circuits, lasers, and detectors coupled to optical fibers. In another application, it is necessary to connect one optical fiber to another. Unfortunately, many of these applications have drawbacks that require careful attention to their manufacture.

  For example, direct connection of the optical fiber to the laser may be hindered because the operating temperature of the laser is not constant and causes different dimensional variations in the fiber and the laser, respectively. Due to the dimensional fluctuation accompanying the temperature fluctuation, the position of the fiber with respect to the laser fluctuates and the separation from the laser occurs.

  Direct coupling is generally inefficient because of the large differences in the dimensional dimensions of the laser and fiber guided modes. This inefficiency is usually solved by using a lens or lens group to focus the light emitted from the laser onto the optical fiber.

  However, further problems arise with optical coupling using the lens or lens group. For example, it is difficult to achieve accurate optical position adjustment between the lens and the laser. Due to dimensional fluctuations and mechanical deviations due to environmental temperature fluctuations over time, the fiber alignment is distorted. Accordingly, there is a need for an improved optical fiber formation method that can improve optical fiber coupling.

  The present invention provides an economical method for producing an optical fiber comprising a lens formed on at least one end of the optical fiber.

  At least one end of the optical fiber is deformed using, for example, a material removal process to form a tapered end or “tipped end”. This chip forming end is further processed according to the present invention, and a condensing lens with adjustable focal length is formed at this chip forming end. Lens tip optical fiber formed by the process of the present invention is used to adjust the position of light with other optical fibers and optical fibers, light sources, planar waveguides, optical integrated circuits, etc. Connection with the device becomes easy.

  In one aspect of the present invention, a method for manufacturing an optical fiber member is provided. The method includes deforming at least one end of the optical fiber member and applying energy to the deformed end of the optical fiber member to form a lens surface.

  In another aspect of the present invention, a method of manufacturing an optical fiber with a lens chip is provided. The method includes providing a light transmissive cylindrical fiber and etching a first end of the light transmissive cylindrical fiber to form a tip. By heating the tip portion, a lens surface is formed on the heated tip portion.

  In yet another aspect of the present invention, an optical fiber is provided that includes a first lens surface formed at a first end of a light transmissive cylindrical fiber. The lens surface is formed by deforming at least one end of the light transmissive cylindrical fiber and applying energy to the deformed end of the light transmissive cylindrical fiber.

  The method for forming an optical fiber with a lens tip of the present invention provides an adjustable radius or focal length of the lens at the tip portion at an economical price. This optical fiber with a lens chip makes it easier to align the light with other optical fibers or various separately integrated optical devices such as light sources, planar waveguides, and optical integrated circuits. Since each optical fiber includes a “built-in” lens, an independent lens can be removed from most optical fiber packages. Removing an independent lens reduces the number of parts required and eliminates the possibility of misalignment between multiple lenses or lens groups associated with a typical optical package. Reduced component count makes optical packages simpler, reduces costly packaging-related labor costs typically associated with optical component packaging and manufacturing processes, and allows for smaller optical packages It becomes. Miniaturization means not only cost reduction but also small system design can be implemented more easily.

  The scope of the invention is defined by the claims, and is incorporated into this section by reference. Those skilled in the art will appreciate a further complete understanding of the present invention, as well as an appreciation of its additional advantages, by reviewing the detailed description of one or more aspects set forth below. A brief description of the accompanying drawings to which reference is made will first be given.

  Aspects of the present invention and their advantages are best understood by referring to the detailed description that follows. Similar components illustrated in one or more figures shall be denoted by similar reference numerals.

FIG. 1 is a flowchart illustrating a process 100 for forming a lens chip on an optical fiber according to an embodiment of the present invention. The process 100 includes providing a single or bundled cylindrical member (s102), such as a cylindrical rod or fiber made of glass (SiO ₂ ) or plastic, for example.

  The first end of each cylindrical member is deformed by removing material to form an etched end, a deformed end, or a tip (s104). In one embodiment, the tip portion is formed by exposing each end of the cylindrical member to a reaction solution that has entered a liquid bath or to be sprayed. In one embodiment, at least one end of the cylindrical member is at least partially immersed in a liquid bath containing a material removal or etchant. In another embodiment, a suitable material removal or etchant is sprayed onto at least one end of the cylindrical member. As will be described in more detail below, a portion of each member is typically etched or deformed by first removing material from the periphery of each member with the etchant. By removing the material from the peripheral portion, a tip portion is usually formed at the end of the cylindrical member.

  In one embodiment, the second end of each cylindrical member is also exposed to the reaction liquid that enters the liquid tank or is sprayed. The second end of the cylindrical member is at least partially immersed in a liquid bath containing an etchant. In another embodiment, a suitable etchant is sprayed onto the second end of the cylindrical member. By removing the material, a tip portion is formed at the second end of the cylindrical member.

  In one embodiment, the tip forming end of the cylindrical member is exposed to an energy source, which heats the tip forming end (s106). As will be described in more detail below, a lens surface is formed at the chip forming end by heating the chip forming end.

  FIG. 2 is a simplified diagram of an etching bath including a cylindrical member 202 according to an embodiment of the present invention. In one embodiment, each cylindrical member 202 can be a rod, cylinder, fiber, or other similar shaped member. Alternatively, the cylindrical member has a non-circular cross-section, such as a square, rectangular, or other polygonal cross-section more suitable for application in some planar waveguides, photonic devices and optoelectronic devices, or non-circular It can be pre-deformed into a cross section.

  The diameter and length of each cylindrical member 202 is typically determined by its application. In one embodiment, the diameter d of each cylindrical member 202 is the same as the length of a standard single mode fiber, with a typical core dimension of about 9 μm and an outer diameter of about 125 μm. In general, the diameter d of each cylindrical member 202 can range from less than about 100 μm to about several millimeters depending on the application. In another embodiment, the cylindrical member 202 can be a multimode fiber.

  In one embodiment, the end 204 of the cylindrical member 202 may be deformed, for example, by removing material using an etching process according to one embodiment of the present invention.

  Referring back to FIG. 2, in one embodiment, the end 204 is deformed by placing the end 204 in the liquid bath 206.

  The liquid bath 206 can include any desired chemical formulation suitable for removing material from the fiber. In one embodiment, the liquid bath 206 includes HF acid 208. A thin oil layer may be added to the liquid bath 206, thereby forming an oil film 210 on the surface of the HF acid 208. By adding the oil film 210 on the surface of the HF acid 208, a boundary for adjusting the depth of the etching process is formed on the acid surface. In general, the depth of etching is controlled by the depth at which the end portion 204 is immersed, but in some cases, the HF acid “lifts” the part beyond the part soaked in HF acid to the non-soaked part. It happens that it is etched unnecessarily. Oil film 210 functions as an etch stop and prevents HF acid from rising over oil film 210.

  The end 204 is placed in the liquid bath 206 for a specific time sufficient to remove the desired amount of material. The time required for material removal is related to the material composition of each member 202 and the composition and concentration of the liquid tank 206.

  In one embodiment shown in FIG. 3, each cylindrical member 202 is composed of a core region C1 and a peripheral region P1 surrounding the core region C1. During processing, the peripheral area P1 is in direct contact with the HF acid 208 and the surface area exposed to the HF acid 208 is wider, so the liquid bath 208 affects the peripheral area P1 before affecting the core area C1. Is affected. This is particularly noticeable in this corner region because the top and side surfaces of the corner region 302 are exposed simultaneously. The type of fiber used also affects how the tip is formed. In some fibers, the core region C1 of the fiber is higher in purity than the peripheral region P1, and the material with a lower purity is easier to remove material.

  The length L of the deformed end portion 304 is adjusted by, for example, the depth at which the member 202 is immersed in the HF acid 208 below the oil film 210. On the other hand, the sharpness (or gradient) S of the deformed end 304 is adjusted by the time that the member 202 is held in the liquid tank 206 and the concentration of the HF acid 208.

  The material removal process of the present invention has the advantage of being a slow process. Therefore, the manufacturer can continuously check the progress of the material removal process, and can remove the end portion 204 from the liquid tank 206 when the end portion 304 reaches a desired dimension.

  The structure obtained by this material removing step is a chip forming member 400 shown in FIG. 4A.

  As shown in FIG. 4A, the chip forming member 400 includes at least one chip forming end 402 and a base 404. In one embodiment shown in FIG. 4B, the tip forming end 402 is exposed to an energy source 410, which heats the tip forming end 402. By this heat treatment, both the core region C1 and the outer edge portion P1 in the chip forming end portion 402 are melted. Due to the surface tension generated as a result of the melting, a curved surface is formed at the end of a part of the member, and a lens surface 408 is formed. The heating position and the amount of energy applied to the tip forming end 402 determine the physical shape and radius of the lens surface 408, thereby determining the focal length of the lens surface 408 formed at the tip forming end 402. The

  The method of supplying the energy necessary to form the lens chip may be any suitable energy generating means including heat (ie, flame), electric spark, electric arc discharge and equivalents in the embodiments described below. Can be achieved.

  Referring again to FIG. 4B, in one embodiment, the tip forming end 402 of the tip forming member 400 is placed in an arc generator 406, such as a commercially available joining device. The arc generator 406 can provide an arc or spark, which can heat the material of any given light transmissive member. By this heat treatment, the lens surface 408 is formed as described above.

  In other embodiments, the heating energy source 410 is a glow discharge disposed near the tip forming end 402 or the lens forming end 402 to heat the material and form the lens surface 408 according to the present invention. A high-power laser having a wavelength that can be absorbed by the material can be obtained.

  FIG. 4C includes a side view of a single light transmissive tip forming member 402 after the heating step according to one embodiment of the present invention. The chip forming end 304 is deformed by heat treatment so as to have different radii of curvature in two directions orthogonal to each other or in other different directions. 4C shows in detail the curved surfaces 412a, 412b, and 412c, such as elliptical, semi-elliptical, and plano-convex aspherical surfaces, which are formed at different positions of the chip forming end portion 402. These curved surfaces are the lens surfaces. Different optical performance can be provided for different optical axes relative to the major axis of 408.

  The portion of the lens forming end 402 where the lens surface 408 is formed is related to the amount of energy applied or heated over the length L of the lens forming end 402 and the length of time exposed to the energy source. In one embodiment, the lens forming end 402 has a length L. When energy is applied to a portion extending over the length L, a lens surface 408 is formed at that portion of the lens forming end 402. In one embodiment, the portion over the length L where the lens surface 408 is formed has an angle or slope of about 15 ° to about 20 °, and is used to couple and package optical fibers or waveguides. Is particularly useful.

  The curvature and dimensions of the lens surface 408 can be adjusted according to the requirements of that particular application. The manufacturing specifications and tolerances of the lens surface 408 are determined by its particular application and are therefore defined by its end user.

  FIG. 5 is a simplified diagram showing an application example of the present invention according to an embodiment of the present invention. In this application example, a standard optical package 500a is compared with a new package 500b including the optical fiber with a lens chip of the present invention. The standard optical package 500a includes a laser module. The laser module includes a drive and environmental temperature control device 502, a laser 504, a lens group 506, an isolation device 508, and a standard optical fiber 510. The lens group 506 condenses the light from the laser 504 and directs and converges the light on the optical fiber 510. Many related parts must be properly aligned and fixed in place. To position different components, each component must be adjustable, and at the same time, properly positioned components must be precisely fixed in place. In practice, a compromise is required to make these components adjustable and fixed in place so that they do not deviate from their aligned positions. Thus, the conventional package 500a can never be optimally aligned, so much of the light from the laser 504 is not directed to the optical fiber 510.

  The new optical package 500b also includes a laser module having a drive and environmental temperature control device 502, a laser 504, and an isolation device 508. However, in this application example, it is advantageous that the lens group 506 is removed and the standard optical fiber 510 is replaced with an optical fiber 512 with a lens chip produced by the process of the present invention. The optical fiber 512 with a lens chip whose focal length and shape are adjusted has a lens surface 408, which condenses most of the light from the laser 504 efficiently and directs the light through the optical fiber 512. This lens surface 408 can be placed close to the output surface of the laser 504 so that it does. Experiments show that an optical coupling efficiency of as much as 80% can be achieved by using an optical fiber 512 with a lens chip manufactured according to an embodiment of the present invention.

  FIG. 6 is a simplified diagram of another application example of the present invention according to an embodiment of the present invention. In this application example, a standard optical package 600a is compared with a new package 600b including the optical fiber with a lens chip of the present invention. The standard optical package 600 a includes an optical component 602 between two standard optical fibers 604 and 606. In order to properly align the standard fibers 604 and 606, lenses 608 and 610 are placed between the optical component 602 and each standard optical fiber 604 and 606. The lens 608 collects light from the input-side optical fiber 604 and converges the light on the input-side waveguide of the optical component 602. The lens 610 on the output side of the optical component collects light from the waveguide on the output side of the optical component 602 and converges the light again on the optical fiber 606. For the alignment of the lenses 608 and 610 with the optical component 602 and the two optical fibers 604 and 606, all components need to be adjusted to an optimal state, whereas for optimal alignment, The part must be precisely fixed in place, which is practically not feasible.

  The new optical package 600b also includes an optical component 602. However, in this embodiment, optical fibers 612 and 614 with lens chips are used instead of standard fibers 604 and 606. Since the optical fibers 612 and 614 with lens tips have a lens surface 408, they are automatically aligned relative to the optical fibers 612 and 614, eliminating the need for several adjustment fixtures for the lens and complex package design. . The new optical package 600b simplifies the package design and optical position adjustment process, and at the same time improves the reliability of the optical package. In addition, a properly designed and tuned fiber with a lens chip improves optical coupling efficiency and reduces the size of the optical package.

  The optical fiber with a lens chip of the present invention can be used for many other applications. For example, the optical fiber with a lens chip of the present invention can be used for position adjustment / coupling of a hermetically sealed lead wire. This lens must be formed on a fiber ribbon to improve connectivity or interconnectivity in various DWDM components, optoelectronic components, optical components, and optical integrated circuits. Can be used and can be used to focus the incident light onto the detector to form a highly efficient receiver. Moreover, this optical fiber with a lens chip can also be used for portable instruments such as laser surgical instruments in various medical fields, micro-imaging, bioprobes, and spectrum analysis.

  The above embodiments are illustrative of the present invention and are not limiting. It will be understood that various modifications and changes may be made in accordance with the principles of the present invention. Accordingly, the scope of the invention is defined only by the claims.

It is a flowchart which shows the process of this invention. It is a simplification figure of the liquid tank concerning one embodiment of the present invention. It is a simplified diagram showing formation of a deformed end portion at one end of a cylindrical member according to an embodiment of the present invention. It is a simplified diagram of the structure obtained from the material removal process concerning one embodiment of the present invention. FIG. 4B is a simplified diagram illustrating a process of forming a lens on a deformed end in the structure of FIG. 4A according to one embodiment of the present invention. FIG. 4B is a simplified diagram illustrating a lens surface with adjustable focal length that can be formed on a deformed end in the structure of FIG. 4A according to one embodiment of the present invention. It is a simplified diagram showing an application example of the present invention according to an embodiment of the present invention. It is a simplification figure showing another example of application of the present invention concerning one embodiment of the present invention.

Claims (20)

A method of manufacturing an optical fiber member,
A deformation step of deforming at least one end of the optical fiber member;
Applying energy to the deformed end of the optical fiber member to form a lens surface;
The manufacturing method of the optical fiber member characterized by the above-mentioned.   The manufacturing method according to claim 1, wherein the deforming step includes a step of removing material from the at least one end portion of the optical fiber member.   The manufacturing method according to claim 1, wherein the deforming step includes a step of etching the at least one end portion of the optical fiber member by exposing the at least one end portion of the optical fiber member to an etching solution. .   The manufacturing method according to claim 3, wherein the etching solution contains HF acid.   The manufacturing method according to claim 1, wherein the optical fiber member includes a material selected from the group consisting of glass, polymer, and plastic.   The manufacturing method according to claim 1, wherein the step of applying energy to the deformed end includes a heating step of heating the deformed end to form the lens surface.   The manufacturing method according to claim 6, wherein the lens surface includes a convex, concave, or planar lens surface.   The manufacturing method according to claim 1, wherein the deforming step includes a step of removing material from both ends of the optical fiber member.   The manufacturing method according to claim 8, wherein the heating step includes a step of heating both ends in order to form a lens surface at each end.   The deformed end has a first length and the step of applying energy places the lens surface in a position on the deformed end having an angle between about 15 ° and about 20 °. The manufacturing method according to claim 1, further comprising the step of applying energy to a position over the first length to form.   The method of claim 1, wherein applying the energy comprises exposing the deformed end to a heat source.   The manufacturing method according to claim 1, wherein the step of applying energy comprises a step of moving the deformed end portion toward a spark. A method of manufacturing an optical fiber with a lens chip, comprising:
Providing a light transmissive cylindrical fiber;
An etching step of etching a first end of the light-transmitting cylindrical fiber to form a tip portion;
A heating step of heating the tip portion to form a lens surface;
A method for producing an optical fiber with a lens chip, comprising:   The method of claim 13, wherein the light transmissive cylindrical fiber comprises a material selected from the group consisting of glass, polymer, and plastic.   14. The etching step of claim 13, wherein the etching step comprises etching the light transmissive cylindrical fiber by exposing the first end of the light transmissive cylindrical fiber to an etchant. Manufacturing method.   The manufacturing method according to claim 13, wherein the etching solution contains HF acid.   The manufacturing method according to claim 13, wherein the lens surface includes a convex, concave, or planar lens surface.   The manufacturing method according to claim 13, wherein the etching step includes a step of etching the first end and the second end of the light-transmitting cylindrical fiber.   The manufacturing method according to claim 18, wherein the heating step includes a step of heating both the first end portion and the second end portion to form a lens surface at each end portion. . A first lens surface formed at a first end of a light transmissive cylindrical fiber, wherein at least one end of the light transmissive cylindrical fiber is deformed, and the deformation of the light transmissive cylindrical fiber is performed. An optical fiber comprising a first lens surface formed by applying energy to the end.

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