Image: Groman123 / Flickr (source) (CC BY-SA 2.0)
Fiber Optic Lighting
In data transmission applications for fiber optics, one device is connected by to another, each one acting as a transmitter or receiver. Typically the light source, or transmitter, is an LED or laser, and the sink, or receiver, is a photodiode. The link length is limited to hundreds of kilometers in ideal conditions, primarily by dispersion.
In contrast, lighting applications use HID, halogen, LED, and other light sources, and one source can feed many fiber light pipes. Different endpoint are available, including simply using bare fiber. The ultimate receiver of this light is the eye. Attenuation and light loss are the limiting factors for run length, which is dozens of meters at best. For this reason, splicing techniques usable for data transmission are out of the question; illumniator placement must be carefully planned instead.
Advantages of POF Lighting
POF brings many advantages to lighting applications, including:
- Long service life
- Heat isolation – Heat generated by the light source is isolated from the illumination target
- Electrical isolation – The power source for the light is isolated from the illumniated target, making it safe in some environments
- UV/IR energy is filtered
Fiber Selection for Lighting
In lighting applications, large-diameter, solid core fiber is typically used. As with smaller fiber used for data transmission, the most crucial factor of its optical performance is the end finish; the ends must be finished with the proper tool for the lowest attenuation. Large-diamter fiber like this is often manufactured without a protective jacket, so care must be taken to protect its caldding from scratches during installation. The fiber’s ultraviolet sensitivity should also be taken into consideration, as excessive exposure to it can cause the fiber to degrade over time.
Fibers designed for light are available in two varieties: End-emitting, where light is directed through the fiber to the end, acting as a spotlight, and side-emitting, where light is scattered along the length of the fiber to create a “neon light” effect.
How Fiber Optic Lights are Made
Fiber optic lights function no differently than fiber optic cables designed for communication, but the fibers used for lighting are often manufactured specifically for lighting applications, with larger cores and thinner claddings. The fibers themselves may be plastic or glass, though the intensity of the light source (illuminator) will have to be taken into consideration in the case of plastic, as it has a lower temperature tolerance than glass.
Fibers are bundled together and mounted at the output of the illuminator, which may be located away from the target illumination point of the light. This is useful in cases where an object should be illuminated, but not heated by the light source.
(2014) The FOA Reference For Fiber Optics – Fiber Optic Lighting [Online]. Available: http://www.thefoa.org/tech/lighting/lighting.html