Fiber Optics and the Light Source
The light source of a fiber system can be either an LED or laser. The type of system you choose depends on the type of project you’re planning to build.
Unlike other lighting systems, fiber optics don’t transmit heat so they can be installed next to delicate art or in chilled display cases.
End-Emitting Fibers
Optical fibers are thin strands of glass or plastic material that transmit light signals quickly. Invented in the 1950s, they are most commonly used to carry light signals for telecommunications. They are also often used in lighting applications to create a variety of visual effects.
In data transmission applications, optical fiber is used to save space in cable ducts because it can transmit multiple channels of information over long distances. It can also fiber-optic-light-source transfer more data than electrical cables of the same size because it can carry many times more information, despite its much thinner profile.
For lighting, optical fiber is nonconductive and can be used to safely deliver illumination in hazardous environments. It can also isolate heat from the source, allowing delicate objects to be illuminated without damage. It also prevents electric shock and allows safe operation in electrically dangerous environments, such as underwater installations or those with explosive materials.
There are many different types of optical fibers. Those most commonly used for lighting are multi-mode step-index optical fibers with large transparent cores and thin, reflective cladding that traps the light within them in an optical process called total internal reflection. They are available in a range of lengths and diameters, and are typically jacketed with flexible PVC for ease of handling and protection. Bare end-lit fibers work best when paired with an appropriate lens to optimize the injection efficiency and beam quality. The resulting beam has an almost perfect Gaussian shape, even over long distances.
End-Glow Fibers
The plastic fibers used for lighting aren’t as sophisticated as the glass bundles that transmit data for telecommunications, but they work on the same principle: Light shining into one end of the fiber travels down the length and emerges at the other end (sometimes called a “light pipe”). There are different kinds of light-emitting fibers, which differ in the way they display light.
One style allows little to no light to show along the strand itself, giving it a neon tube look; this is called end glow or point glow. It’s useful for creating a very bright, small spotlight effect. On the other hand, side-glow fibers allow a lot of light to display along the entire strand and have a more continuous glow. The latter is most popular for wearables, where you can use the fibers to illuminate a pattern on your fabric, or to create a glowing strand that follows the shape of your body.
You can also manipulate the cladding on the outside of a standard end-glow fiber to give it an all over sparkle. This can be done by rubbing the cladding with sandpaper for a diffused look, or using an xacto knife to cut into the fiber to reveal points of light. The color of the light that is emitted from the fiber depends on the type of lamp or other source that is used. Illuminators usually include moveable filters that can be changed to produce various colors of light within the fiber.
Solid Core End Glow Fibers
In lighting applications, the strands are used to channel light from a point source (often called a fiber optic illuminator) to a desired location. This light can either be emitted from the end of the fiber creating a small spotlight effect (end glow), or it can be emitted along the entire length of the fiber looking like a neon or fluorescent tube (side glow). The type of light produced is dependent on the core and cladding materials, as well as the size of the core and cladding diameter.
The core acts as a clear path for light to travel through the fiber while the cladding is designed to act as a one-way mirror that reflects any stray rays back into the core. This allows light to travel long distances through curves and around corners without losing significant power, emerging at the other end almost as bright as the original source.
The type of light produced is also dependent on the core and cladding materials, the size of the core and cladding, included filters (if any), and even the cleanliness of the fiber ends. Generally speaking, larger diameter cores tend to couple more power than smaller diameter ones. In addition, the more surface area on the cladding at the core/cladding interface, the more light is able to be coupled.
Side Glow Fibers
Side Glow Fibers are similar to end-emitting fibers, but with a different construction. They’re available in a variety of diameters and have a more uniform cladding fiber optic cable assembly industry along the entire length. This creates a more consistent glow that looks like a strand of neon or el wire. They’re much more effective in dim or dark light, and they’re also easier to hide inside your costume.
Most of the side glow harnesses I’ve found are made overseas, though Wiedamark and The Fiber Optic Store do sell a few domestic options as well. They’re constructed with strands of PMMA acrylic optical fibers that are twisted into sub-bundles and surrounded by a flexible clear jacket. These harnesses are fitted with a standard 30mm common end for connecting to your fiber optic illuminator, and they’re suitable for use indoors or outdoors.
They’re a little more visible than end emitting fibers in ambient light, and require more powerful LEDs to operate at full brightness. A 1 watt LED can run about 5-8 meters of 3mm side glow fiber without noticeable deterioration in the quality of the light, but longer runs will require more powerful or repeater LEDs. These harnesses are often used for illuminating walkways and other exterior applications, but they can work well in the right costume as well. They’re perfect for adding a touch of magic to your space, illuminating a room, or transforming an event into a mesmerizing wonderland.