Optical fiber

Try putting the fiber end into an electric arc fusion splicer. It will take some experimentation to get the arc parameters right to get the shape you are looking for.

Mr. Rodney,

Optical fiber is very tricky to work with. Now with this in mind, the process will depend on various issues about the fiber you are working with. Plastic or Glass, diameter of fiber, what type of cladding it has, and finally the quality of fiber. Yup there is a quality and the quality will determine if you can alter the factory shape with ease.

Step 1 if glass; use small dremel and a hard grinding wheel (Purple), position the wheel at the desired angle you want the tip of the fiber to have. Next have a collet type device to hold the fiber in place (make sure this device can rotate my means of a constant motion, not intermitent). Finally make sure the dremel is on a sliding mechanism allowing you the ability to control how much material you want to take off at a time. Speeds; dremel running at high speed, fiber turning at low speed.

You wont need any lubrication, that will only blur your vision and you will need to watch very closely on your process. (Use microscope)

Step 2 if plastic; use micron sandpaper and engineer a tool (widget) to hold the fiber at the desired angle then sand in figure 8 motion. Most likely you will need to use several different grits of paper till you get the finish you need or want.

Hope this helps. BTW this may sound somewhat easy but you will need some R&D time to develop your process to get or acquire the finish you want on the fiber.

whether the figure 8 polishing can be used for the glass fiber.if so then how can i make ensure that the fiber is moved in figure 8 motion uniformly .can I know the angle I should keep so that after polishing Of the optical fiber the laser beam emitting out of fiber is having partcular focal length.whether i have make a set up for that.

I have produced nice spherical/globular deformations of optical fibers by placing the tip of the fiber close to a heat source, such as the small electric soldering iron.

use a variable heat gun. but yes the heating idea can work however the tip of the fiber will then have a melted apperance under a microscope which will effect the light output. Polish the fiber tip after the heating technique is complete. be sure to understand that any shape you create on the tip of the fiber will drastically effect your output that is if you are trying to have clean and clear light output. If you are using this for information transfer then, the it won't matter.

Do remember this technique is only good for plastic fiber, not glass. Glass requires much more heat to reshape itself then plastic.

From FreePatentsOnline

Title: Micro lens formation at optical fiber ends Document Type and Number: United States Patent 4118270 Link to this page: http://www.freepatentsonline.com/4118270.html Abstract:

Method of formation of lenses at optical fiber ends to increase the coupling efficiency thereof. In a first embodiment, the end of the optical fiber is masked with a substance non-soluble in the etching reagent. The portion of the coating at the very end of the fiber is then removed and the fiber end immersed in an etching reagent. The etching reagent serves to dissolve the uncoated portion of the fiber. By controlling the amount of time that the fiber end is in the reagent, different lens shapes may be formed. In a second embodiment, the fiber end is dipped into a liquid epoxy compound whereby a portion of the epoxy is deposited onto the fiber end. The surface tension of the portion deposited thereon draws the liquid epoxy into the desired lens shape. The epoxy is then hardened to form a permanent lens structure on the fiber end.

j.

The optical fiber I am using is fused silica with core dimension of 200 microns .what is the method I should follow while preparing spherical optical fiber tip so that the optical fiber will have particular focal length.

The simplest as far as tooling and process is using a fusion splicer.

As stated in #1, you will need to play with process parameters.

If this is for a product, I think Corning holds a patent on it.

Alternatively, H₂O₂ flame is used for fiber stretching, and will do what you need, under controlled circumstances.

Also Laser machining is used in the industry for pig-tailing FBG pump stabilizers. It may be simple to implement if you have a CO₂ laser available.

A large part of our experience is FBG manufacturing automation, so we would gladly provide further assistance.