The Beginners Guide to Fiber Optics

The fiber optics I'm dealing with in this Instructable are the plastic fibers designed for lighting, not the slightly more sophisticated glass fiber bundles that transmit data rapidly over long distances, but they function on the same basic principle: Light shining in one end from a source of illumination, like an LED or a laser, travels down the fiber optic strand and emerges at the other end.

A standard "end emitting" fiber optic designed for lighting is a long thin strand of plastic consisting of a very clear core and an external coating called a cladding. (Another name for this type of structure is a "light pipe").

The clear inner core allows light to travel unimpeded down the length of the fiber while the cladding acts like a one-way mirror, containing any light that tries to escape the fiber by bouncing it back into the core in a process called total internal reflection. This combination of core and cladding allows light to travel along the fiber for great distances, even around curves, emerging at the other end nearly as bright as the original source of illumination.

Depending on the quality of the fiber however, some amount of light may degrade, or be lost along the way. Some fiber optics make use of this light degradation, allowing a little light to escape through the cladding along the length of the fibers, thus creating an even glow that looks a bit like a neon tube. These fibers are called "side emitting" fiber optics.

2 More Images

End emitting and side emitting fibers have a slightly different look and are good for different purposes.

End emitting fibers (also called end glow, or end light) are the classic fiber optics, with bright points of light at the ends and very little light escaping along the strands themselves. They are usually thin, somewhere from .25 to 3mm in diameter. They are also generally stiffer than the side emitting fibers.

End emitting fibers are great for directing individual points of light far from a single light source. Projects like the Star Map in the second photo above make use of the ends of the fibers to spread the light from just a few points of illumination into a myriad of tiny stars.

End emitting fibers do leak a little light along the strands however, and when gathered into bunches, this light becomes visible in the dark, as you can see in projects like Natalina's Fiber Optic Dress and Coat and my Fiber Optic Fairy Wings above. You can also strategically nick or abrade the fibers to create points of light along their lengths. (I'll talk more about this later).

I think projects like these are a great use of end light fiber optics because they use both the points of light at the ends of the fibers and the dimmer light along the strands as visual design elements. Allowing some of your end glow fibers to hang freely is also very visually pleasing and creates a mesmerizing light-painting effect when you move.

I have found that end light fibers below about .75mm (which seems to be a fairly standard size) don't emit light along the strands as much, so if you want that kind of glow, choose a larger fiber.

2 More Images

Side emitting fibers (also called side glow, or side light) are usually larger and more flexible than end emitting fibers. They seem to be available anywhere from 2mm to 12mm in diameter.

Because of the way they are constructed, with a cladding that is intentionally less effective, light gradually escapes along the whole length of the fiber creating a fairly even glow almost like a neon tube or el wire.

However, as you can see in the second photo above, some light also escapes from the end of the fiber creating a bright point of light where the fiber is cut.

The intensity of the fiber's glow depends on the intensity of the light source. For example, a 1 watt LED or a laser will illuminate the fiber more than a neopixel LED. The glow of the fiber is also brightest close to the source of illumination, and fades gradually, or sometimes discolors, as more light escapes along the length of the fiber. I have found that the glow of a side light fiber optic, lit with a regular neopixel LED at full brightness, becomes difficult to see, and slightly yellowed, about 5 feet from the light source.

You can combat this dimming by putting a light source at both ends of the fiber as I've done in the third photo above. This can also create amazing blended color effects by having different colored LEDs at each end of the fiber. Even putting a small mirror, instead of a second LED, at the other end of the fiber helps keep the light contained, making the whole strand brighter.

Side emitting fibers are much more visible in ambient light than end emitting fibers, but they still create a diffused glow that looks better in darkness. Side emitting fibers are great for projects where you want defined lines of light rather than pinpoint sparkles. They would also be good for creating inner glow or under-lit elements of a project where you don't want to see the fibers directly.

In addition to the basic distinction of side glow and end glow, you will likely encounter some of the following variations in your search for fiber optics:

Multi Strand End Glow Cable: this is a collection of end glow fibers bundled inside a plastic casing. I have seen these with thick black casings designed to block all light except at the ends of the fibers, or in clear casings which allow you see the fibers all the way along the cable. Usually these cables are filled with fibers of all the same diameter, but I have also seen cables like these that contain a few slightly different sized fibers for variety (they are designed for making star effect ceilings). Buying fiber optics in this form can be useful especially if you are planning to use the fiber in bundles and you want to make sure all your fibers curve in the same direction. Taking the fibers out of the casing can be a little tricky however, and often results in nicking the fibers in places.

Sparkle Cable: groups of end glow fibers intentionally nicked along the strands and bundled in a clear casing to create a sparkle effect. I personally think they look a bit cheesy, but I'm sure they would be great for some projects.

Multi Strand "Side Glow" Cable: Unlike the end glow cables, which contain straight fibers, the fibers inside these clear cables are twisted, ostensibly to allow more light to escape along their length. Like a lot of fiber optics, they seem to be designed for interior decor lighting, but after ordering and testing a sample of these, I really don't see that they have any advantage over large solid core side glow fibers, and they don't seem to work very well. I wouldn't recommend them for wearable projects.

Solid Core End Glow (not pictured): These are single strands up to 14mm in diameter encased in black PVC casing. I haven't actually used these, but they seem to be more like a side glow fiber that is encased so that light will only emerge from the end. They are mostly used in displays and water features to channel light to specific points. They could potentially be useful in wearables for a similar purpose.

These types of fiber optics are a little harder to find, but have a lot of design potential.

White Core Side Glow Fiber, or Light Pipe: These are similarly flexible to the clear "solid core" side glow fibers, but have a white core embedded in the center of a clear strand. The white core illuminates and radiates light into the clear section, making this fiber look much more like el wire as you can se in the first photo.

These fibers only seem to conduct light a few feet down their length before it fades and yellows, but they have an interesting look and could be great for certain projects.

Solid Fiber Optic Ribbon: I first saw these as the light in the inside of illuminated ankle bracelets for biking, and later in a pair of costume suspenders I found a Michael's crafts. As you can see in the second photo, these fibers are basically just like other large end glow fibers in a slightly different shape. Their glow seems to appear more visible when they are encased inside fabric or another diffusing material like they are in the suspender s in the third photo above. I am not even sure if these ribbons are technically fiber optics or just another plastic material that transmits light fairly well, but I think they have a lot of potential for interesting uses.

Woven Fiber Optic Ribbon (not pictured): A flat ribbon-like strip created by weaving thinner fibers loosely together. I have never used these, but they look like they might definitely be great for wearables.

Corning Fibrance: A new product from the Corning glass company that is a very thin and flexible fiber with a structure similar to a white core light pipe. Corning powers their fibers with lasers instead of LEDs which makes them significantly brighter with a look very similar to el wire as you can see in the last photo. This product has a lot of potential, especially for incorporation into textiles, but at the moment it is quite expensive and not readily available to the consumer.

A few companies have started weaving fiber optics into textiles to create illuminated fabric. This is in theory an awesome idea, but so far I haven't been that excited by the results.

The fibers being used in these textiles are end glow fibers that have been strategically abraded to release light along the length of the strands, and the resulting fabric is fairly stiff and coarse. The fibers are usually woven in one direction (warp or weft only) and they need to be bundled and connected to a light source at one end. This greatly limits how the fabric can be cut if you want to retain glow in all the fibers, which means you can only use the fabric in garments with certain kinds of pattern shapes. All this can be worked around, but it is certainly not the easiest material to deal with.

Personally, I also find the aesthetic of the fabric itself to be a little tacky if it isn't used right. I have seen it illuminated with moving lasers, or programmable lights in ways that give it a more dynamic, subtle look. Strategically abrading the fibers to add patterns of light to the fabric can also create beautiful results. I haven't played with this material much myself, but it is definitely an interesting possibility for wearable projects, and I'm sure it will continue to be developed in new and exciting ways.

The possibilities for lighting fiber optics range from simple to extremely complex, and can make a huge difference to the look of your project. When you are choosing lighting, keep in mind that the brighter your light is, the more visible your fiber optic illumination will be. Also, from a personal aesthetic perspective, I think staying away from out-of-the-box primary LED colors like green, blue and red, helps keep a fiber optic project from looking like a cheesy Christmas decoration. I usually go for blended or de-saturated colors for a more subtle and beautiful effect.

LED Lights:

Simple battery powered on/of lights like these floralights which come in variety of colors are a good option for very basic fiber optic illumination. Their shape makes them easy to attach to a bundle of fibers (or a single large fiber) using just heat shrink tubing and glue. There are a lot of pre-packaged lighting options like this available that can provide simple and beautiful illumination to your fiber optic project.

Programable LEDs:

To take full advantage of the dynamic lighting possibilities of fiber optics, however, you really need programable lighting, or at least a light source that has been pre-programmed.

One relatively simple way to do this is to use individually addressable RGB LEDs with a microcontroller. I am just barely beginning to learn Arduino programming, but even with a minimum of knowledge, it is fairly easy to find interesting lighting programs online and load them into your microcontroller. I talk about how I've done this in more detail in my Fiber Optic Fairy Wings Instructable, and there are many other great Instructables that go into much more detail about programing LEDs.

Another, even easier way to access some great lighting programs, is to buy a pre-programmed chip like the Cool Neon Driver I used in my LED skirt project and wire that to addressable LEDs. This will give you many different lighting patterns to choose from and can be controlled by a remote.

Pre-Made Fiber Optic Products:

You can also buy pre-made products that are designed to light fiber optics. Natalina made her dress and coat using a fiber optic whip that comes pre-assembled with a large bundle of fibers attached to a bright RGB LED with many pre-loaded programs. In many ways these whips are great products, but the battery life is not as good as it should be and the shape and size of the whip is not particularly well suited to wearables.

Smaller, cheaper products like glowbys and fiber optic center pieces can also easily be incorporated into wearables, but they don't give you any ability to change the color of your lights, and they are often cheap and poorly made. They are definitely the lowest common denominator of fiber optics, but with a little creativity, they can still be a good addition to your costume.

Lasers:

Another option to light your fiber optics is to use small laser modules. I haven't personally experimented with this, but I have seen it done, and it definitely makes the fibers much brighter and more daylight visible. One constraint is the available laser colors which are relatively limited. The best use of lasers in fiber optics that I've seen was when someone hooked a rotating laser up to fiber optic fabric so different colors and patterns played over the surface of the fabric.

Before attaching the fibers to your light source, you also have to be sure that the end of your fibers are cut cleanly to allow the maximum amount of light to penetrate.

The side glow fibers, which are softer, can be easily cut with a sharp xacto knife, but it's harder to get a clean cut on the harder end glow fibers. For small bundles that have been heat shrunk together, a sharp xacto can work, but for larger bundles, using a hot knife is a good idea. You can find a good explanation of the process in this Instructable.

3 More Images

One of the most important things to think about when you are planning a fiber optic project is, "how am I going to attach my fibers to my lights?" It's crucial create a clean strong connection between your light source and the ends of your fibers so that light shines directly into the fibers and makes them glow as brightly as possible. A big challenge in this is the fact that the fiber optics themselves are quite slippery and don't adhere to most glues very effectively. I have found that superglue and some epoxies seem to stick the best, but you have to be careful not to get superglue on the end of the fibers where is can cause clouding that effects light transmission down the strand.

As I mentioned in the previous step, standard 5mm diffused LEDs are fairly easy to attach to fiber optics because you can slip a heat shrink tube over both the LED and the fiber optic bundle, shrink it down, add a little glue and you have a fairly strong connection between the two (see first photo). You can buy RGB addressable LEDs in this form from places like Adafruit, so you don't need to sacrifice programability. This Instructable also shows how to achieve a similar connection using Sugru instead of heat shrink.

If you are using LED strip to light your fibers, connecting them gets a bit trickier because the LEDs have such a low profile, there isn't much to connect to. Everyone I know who works with fiber optics seems to have come up with their own solution to this problem.

Ashley Newton, who first introduced me to side emitting fiber optics, and worked with me to create my Sea Warrior outfit, has a very effective method that involves 3D printing a piece that holds the LED strip and has nodes with holes that the fiber optics plug into above each pixel (see photos 2 and 3 above). Variations on this shape can be 3D modeled to fit the form of what you are creating. I talk more about this method in my Fiber Optic Sea Warrior Instructable.

For a recent project I also created a double sided version of these LED nodes that holds a folded LED strip allowing fiber optics to emerge and be illuminated from both sides (photo 4). In another piece of the same project I used 3D modeling to create a module that held a 12 a neopixel LED ring with holes above each pixel for a bundle of fiber optics (photo 5).

Jenn Mann who also makes amazing fiber optic wearables, has found a way to use layers of laser cut acrylic to create a similarly shaped connecting strip between LEDs and fibers.

For my Fiber Optic Fairy Wings, I used a much simpler, and slightly jankier, method. I bundled my end glow fibers into groups of about 30, then heat shrunk the ends together and cut them with an exacto knife to create a smooth edge. I installed my LED strip inside a small box with holes drilled in the sides, then fed my fiber optic bundles through the holes and hot glued them into place up against the LEDs, being careful not to get any hot glue between the ends of the fibers and the LEDs as that would block light from illuminating the fibers (last photo).

This worked fairly well, though some fibers in the middle of the bundles were still loose after I had glued them in. Since I was going to be sewing all my fibers down very securely anyway, this didn't really matter, but I would like to find even better ways make sure all the fibers are secure.

3 More Images

Another important consideration for wearable fiber optic projects is, how to attach the fibers to the garment or accessory you are making. Depending on how many separate fibers or bundles of fiber you are working with, this can be a time consuming process, and I'm always looking for new ways to solve this problem.

The most basic way to attach fibers directly to a garment is hand sewing. This is how I attached the fibers to my fairy wings in the first photo. Hand sewing down bundles of fiber optics is pretty time consuming and it takes a bit of skill to make it look neat, but it does work well, and it gives you a lot of room to create freehand layouts. I usually use a thin fishing line or clear thread to sew down the fibers, which ends up being almost invisible against the fibers.

Another way I like to integrate fibers into my designs, especially the larger side light fibers, is by sewing channels into two layers of sheer fabric and inserting the fibers into these channels, almost like creating my own large scale fiber optic fabric (see photos 2 and 3). This is a slightly less time consuming way to contain the fibers, and it creates a nice effect by making the fibers appear to be hovering in midair when it's dark.

I also like to use a technique that involves laser cutting slits in thin leather and then weaving the fibers through these slits as seen in photo 4 (In this photo I've actually used el wire, but it works the same way). You could also do this by hand with an xacto knife. I used this technique on the chest piece and shoulders of the Sea Warrior outfit. It can even be modified to create more complex woven looking patterns with the fibers.

On designs like the Sea Warrior headpiece, the 3D printed nodes that marry the fibers to the lights also function as a means of attaching the fibers to the headpiece (photo 5). Because they are only a few inches long, they can plug into the nodes at the base and then fan out freely.

If you only want to see see the points of light at the the ends of the fibers, you can hide most of the fiber inside a garment (like NLED-Projects did with this Fiber Optic Top Hat) and just attach the strands so the ends are visible as shown in the last photo above.

I haven't experimented that much with manipulating the form of the actual fibers themselves, but there are a few possibilities here that could have some very interesting results.

Nicking or abrading end glow fibers:

Damaging the cladding on the outside of an end glow fiber will allow light to escape and creating a point of glow on the fiber. This can be done with sandpaper for a more diffused look, or with an xacto knife or other sharp object to create individual points of light. This is how the fibers in sparkle cable and fiber optic fabric are manipulated to give a more all-over sparkle.

Using sandpaper on fiber optic fabric creates patterns of brighter glow in different areas. With the right kind of masking and strategic abrading, I think this technique has a lot of potential to make fiber optic fabric more exciting. Of course you have to be careful not to sand too hard, or you might damage the threads that are holding the fabric together. Also keep in mind that the more you abrade the fibers, the less light will continue to travel down the rest of the fiber, making them a little dimmer at the ends.

Distorting fibers with heat:

If you want to create larger points of light at the ends of end glow fibers, you can use a lighter or heat gun to melt the very ends of the fibers into a ball of plastic.

While attempting to straighten some fibers for a project, I accidentally melted some with an iron causing them to curl up in odd ways. I thought this actually looked pretty interesting a little like a Chihouly sculpture or a sea creature. It also made the fibers glow brighter

I've already talked about a lot of my favorite fiber optic projects, but here's a longer list of great inspiration that will show you some of the beautiful things you can create with fiber optic lighting.

Instructables:

Fiber Optic Dress

Fiber Optic Coat

LED Fiber Optic Jellyfish Skirt

Fiber Optic Fairy Wings

Made With Magic Fiber Optic Wings

Lightwings

Fiber Optic Sea Warrior

Fiber Optic LED Top Hat

Make a Fiber Optic Flower

Installing Fiber Optics Into an Illuminator

Fiber Optic LED Bling

Night Shower LED Earrings

Skirt Full of Stars

How to Get More Light Out of a Single Strand of Optical Fiber

Star Map

Sky on The Wall

Fiber Optic Dandelion Lamp

Fiber Optic Jellyfish Lamp

Also check out the work of:

Sustainable Magic

Jenn Mann

Rachel Reichert

Elena Kozlova

Bulk fiber optics are still not widely available as a retail product, but they are not hard to find if you know where to look. If you are planning a project that uses fiber optics, I recommend starting to gather your materials a few weeks ahead of time because the best sources are often overseas. Make sure you read the rest of this Instructable before you dive into ordering so you understand exactly which fiber optic product you are looking for.

End Glow Fibers

• Easier to find domestically than side glow and can be ordered from places like Wiedamark, The Fiber Optic Store, and many others
• Alternately, you can buy pre-made products like fiber optic whips or glowbys and use the fibers from them for your project
• To order direct from factories in bulk, search sites like AliExpress, Alibaba or Ebay

Solid Core Side Glow Fibers

• For the best prices, order them in bulk from China by looking on AliExpress, Alibaba or Ebay
• If you need smaller quantities, or faster delivery, Wiedamark and The Fiber Optic Store offer a few domestic options for side glow fibers as well.
• One thing to be aware of when ordering side glow fibers is that they often come with a thin clear PVC casing to protect them from UV light damage. If you are using them outside, this is great, but for wearables it can make the fibers a lot less flexible. It also means that the diameter quoted in the product listing is often the internal diameter, not the diameter with the casing. I try to buy fiber like this, that don't have an casing.

White Core Side Glow Fibers

• They used to sell these on Sparkfun in 3mm and 5mm diameter, but they seem to have discontinued them. Right now I only see it being sold from a couple of European distributors.

Solid Fiber Optic Ribbon

• I've had a hard time finding a good source for this type of fiber online. I recently ordered some from China on Ebay but it was not exactly the shape I was hoping for. Slightly more rounded and not quite as wide as the kind I found inside the suspenders, but it is still an interesting product.

Woven Fiber Optic Ribbon

• A type called Flexglow is available from Fiber Optic Products.

Fiber Optic Fabric

• Small 40 x 75 cm pieces can be ordered from Sparkfun, only in a black colorway.
• Larger quantities in more fabric color variety and density of fibers can be ordered by contacting Lumigram.

Corning Fibrance

• Still only available from the manufacturer and you need to email them for quotes. The fibers seem to be about $9/meter and their proprietary laser modules are quite expensive.