NALUX NANO OPTICAL, INC. 

65 E.State Street, Suit2000
Columbus, Ohio 43215
c/o Schneider Downs
Attention:Dennis R.Mowrey

Email: sales@nalux.co.jp

"Lighting a path to the future with nano-optics."





Optical Waveguides 

Optical waveguides are optical elements that are a lot like traditional copper wire in that they are simply a conduit directing light waves in a specific direction.  Optical fiber is actually classified under optical waveguides except the term normally refers to small components that go into optical systems while optical fibers can be miles long.  

The basic mechanism that allows optical waveguides to do their job is called internal reflection.  This term refers to the fact that all materials that allow light to pass through them have a property called refractive index, which is a measure of how much the material slows the light down as compared to the speed of light in a vacuum.  Internal reflection refers to the fact that when light tries to pass from one material to another as it does in optical waveguides, reflection takes place at the interface between these two different materials because they have different refractive indices.  Optical waveguides are designed so that they take advantage of this fact to keep light in the central core material.  The outer material could be another material with a different refractive index or it could simply be air.  Either way, these elements do their job by keeping light inside the core material and not letting it leak out the sides so that the light is taken from one place and is directed to the place we want it to go.  

Another type is known as strip waveguides.  This kind uses a central core material which is sandwiched between two layers of cladding material.  Cladding is simply the name given to the material that is used to keep the light in the core material of optical waveguides.  

There are several different manufacturing methods for making optical waveguides.  One of the easiest methods is by diamond milling although this method isn't cost effective for making large quantities.  If large numbers of the same optical waveguides are needed, the best method to use for mass production is glass molding.  To make optical waveguides using glass molding, the molds must be created.  The molds are a top half and a bottom half and the glass charges, which will become the optical waveguides, are loaded into the bottom half of the mold.  The mold is then closed and heat and pressure are applied to the top half of the mold so that the glass charge melts and flows and fills the mold cavity.  The advantage of the glass molding method when making optical waveguides is that the shape can be controlled very accurately and it is very repeatable.  Additionally, the cycle time is fairly short so it is much less expensive to make optical waveguides using this method than to use diamond milling.   

An additional manufacturing method is by using mask lithography and plasma etching.  This method entails patterning a wafer of glass using photoresist and then etching the shape of the optical waveguides directly into the glass itself.  Finally, the most inexpensive way of making optical waveguides is by plastic injection molding.  While the tooling costs can be high since molds for optical plastics are the most high precision molds you will find, the price per part can be on the order of $0.10 to $0.20 depending on the number of parts needed and the plastic material required.  It can be so inexpensive to make optical waveguides this way because the mold could have as many as 32 cavities and the cycle time can be as fast as 30 seconds.  All these reasons make plastic optical waveguides a great option for optical systems.  

So, whether you need glass or plastic, one piece or millions of pieces, Nalux is the one to call whenever you need optical waveguides.