FIELD OF THE INVENTION The present invention relates, generally to the field of microstructured fiber technology. More particularly, the present invention relates to an apparatus for use in mounting a capillary in the fabrication of a flat microstructured fiber.

BACKGROUND OF THE INVENTION

In the last 30 years, optical fibers have been used to replace copper cables in the modern telecommunications network. This is due to the numerous advantages of optical fibers (when compared to copper cables) such as having a large potential bandwidth, low transmission loss (less than 0.2 dB per km), a smaller size, electromagnetic interference immunity and low manufacturing cost.

An optical fiber has a circular cross-section, normally with a circular solid core and cladding. A single mode optical fiber typically has a diameter of 125 μηι and a solid core with the diameter of 9 μηι. Light is guided inside the optical fiber through a total internal reflection which requires the refractive index of the core to be higher than the cladding. The cladding is usually made of fused silica without any dopant and the core is normally doped with dopants such as Germanium to get a higher refractive index. Flat fibers are different from other optical fibers due to their planar cross- sectional region. Having a wider cross-sectional area has opened the flat fiber to various functionalities which allows such modifications to be embedded on the fiber itself, which is not possible in the conventional optical fibers. The flat fiber can be described as a ribbon-like planar sample that has extended length and fully flexible substrate. Hence, the flat fiber comprises a combination of both structural advantages of the optical fibers as well as functional benefits of the planar devices. The planar devices are commonly built on rigid substrates, i.e. silicon wafers, which are not mechanically flexible. Photonic crystal fibers, a member of microstructure optical fibers, and a class of holey fibers, produce light guidance effect through a pattern of tiny holes which run along the entire length of the fiber. The photonic crystal fibers employ a microstructure arrangement of material in a background material of different refractive index. Typically, an undoped silica is chosen as the background material and a low index region is provided by air voids running along the fiber's axis. The core size of the fibers is varied as to make the fibers: first, to have either very low or very high optical non-linearity, and second, capable of light transmission in air through photonic band gap effect (Cregan et al, 1999).

A flat microstructure fiber has a shape that is similar to the flat fiber but comprises air holes (in one row or more) running across its photosensitive core. The flat microstructure fiber provides a versatile platform which makes it capable of fabricating various optical components via UV writing on the photosensitive core of the flat microstructure fiber. However, one of the main challenges in the fabrication of the flat microstructure fiber is that to mount the capillary which form the air holes such that no deformation occurs.

A need therefore exists for providing technology allowing for economically exploitation of an apparatus for mounting a capillary in the fabrication of a flat microstructured fiber. Thus, the present invention seeks to provide a relatively cost-efficient apparatus that is capable to mount the capillary. Therefore, a need for the aforementioned apparatus is met. SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

Accordingly, the present invention provides an apparatus to mount a capillary for fabricating a flat microstructured fiber. The apparatus comprises a first member configured for holding a preform; and a second member coupled to the first member having an extension extending from the body for engaging a portion of the capillary positioned in the preform. The apparatus further comprises a connecting member that is configured for coupling the first member and the second member. One end of the connecting member is sealed to the first member to prevent vacuum leak. Another end of the connecting member is coupled to the second member by fastening means. The fastening means, preferably, is a detachable lock pin. The apparatus also comprises a vacuum hose engaged to the first member for providing a vacuum.

The portion of the capillary has at one end a deformed portion. The deformed portion is a hook-like which is configured to grip the extension at the second member. The capillary may be a plurality of capillaries. The extension, for example, can be means for resting the deformed portion of the capillary. Preferably, the extension is a hook bar.

It is an advantage of the present invention to provide an apparatus to mount the capillary that is simple to manufacture, easy to install and use and space efficient.

It is another advantage of the present invention to provide an apparatus to mount the capillary for use in the fabrication of the flat microstructured fiber that is capable to minimize air hole deformations of the fiber.

The foregoing and other objects, features, aspects and advantages of the present invention will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein :

Figure 1 shows the apparatus to mount the capillary;

Figure 2 shows the capillary for use with the apparatus; and

Figure 3 shows the capillary which is mounted to the apparatus. DETAILED DESCRIPTION OF THE INVENTION

It is an object of the present disclosure to provide an apparatus 100 to mount a capillary 200 for use in the fabricating a flat microstructured fiber. Preferably, the flat microstructured fiber allows light to be guided either through the total internal reflection or photonic band gap effects, while having a versatile planar shape.

Figure 1 shows the apparatus 100 which comprises a first member 101 . The first member 101 is configured to hold a preform 300. The first member 101 has a slanting shape with varying diameter so as to accommodate various sizes of the preform 300. The first member 101 is coupled to a vacuum hose 102. The vacuum hose 102 may comprise a vacuum valve that is connected to a pressure system. The vacuum hose 102 is configured to provide a vacuum for drawing process upon fabricating the flat microstructured fiber. The first member 101 is coupled to a second member 104. It is understood by one skilled in the art that the apparatus 100 can be made of any materials which is suitable to the drawing process such as brass and stainless steel.

The second member 104 is coupled to the first member 101 by a connecting member 103. The second member 104 has an extension 106 which is extending from the body of the second member 104. The extension 106 is formed for engaging the capillary 200 within the preform 300. The second member 104 is attachable to the connecting member 103 by fastening means 105. The fastening means 105 is preferably a detachable lock pin. The second member 104 and the connecting member 103 are adapted to be adjustable in term of the height where the second member 104 can be coupled to the connecting member 103 at any position along the wall of the connecting member 103.

The extension 106 of the second member 104 can be any means for resting a portion of the capillary 200. The means for resting can be, for example, a hook bar. The extension 106 is designed to adapt and support various designs of the portion of the capillary 200 as well as to support arrangements of the capillary 200 which can be a plurality of capillaries that are arranged within the preform 300. The capillaries may be hold in place using a sealant which can be made of the similar material as the capillaries. The extension 106 is not limited to be shape of a straight bar, but can be any shape as long as the extension supports the capillary 200. The extension 106 can be, but not limited to a leg, foot, fin, protrusion and/or the like. Example of the capillary 200 that is mounted to the apparatus 100 via the extension 106 is shown in Figure 3.

One end of the connecting member 103 is sealed to the first member 101 . Another end of the connecting member 103 is releasably fixed to the second member 104. The connecting member 103 is configured to direct the vacuum as well as to prevent vacuum leak during the drawing process. It is preferred that the apparatus 100 is a hermetic seal which is airtight and allows vacuum to flow into the preform 300. In another preferred embodiment, the first member 101 , the second member 104 and the connecting member 103 can be integrally formed.

Figure 2 shows the capillary 200 which has the distal end 201 and proximal end 202. The capillary 200 which can be made of material such as fused silica has the portion of the distal end 201 that is deformed. The deformed portion of the capillary 200 is configured to grip the extension 106 of the second member 104 for engagement during the drawing process. It is preferred that the deformed portion is a hook-like. However, the deformed portion can be any other shapes which have the similar significance. The deformed portion also can be a bent, clasp and the like.

The preform 300 can be made of similar material as the capillary 200. For example, the preform 300 is made of fused silica. While this invention has been particularly shown and described with reference to the exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.