Fiber optics (component)
In the field of optics of the same name, fiber optics or fiber optic elements denote an optical component made up of one or more optical fibers (e.g. glass fiber ) or light conductors for the transmission of electromagnetic radiation or optical signals. Based on the English term fiber optics , fiber optics are also referred to as fiber optics or fiber optics .
Fiber optics are used in many areas, for example:
- in communication and communications technology for information transmission at high data rates ,
- in spectroscopy for recording signals and supplying them to the spectrometer using fiber optic sensors ,
- in medical technology for the transmission of image signals in areas that are difficult to access (such as in endoscopy ) or
- in lighting technology for the transmission of radiated power for point lighting (e.g. star projectors ) or lines.
Medical technology
There are two types of fiber optics in medicine:
- Fiber optics fused together to form a mechanically homogeneous block, and
- flexible fiber optics of an endoscope , which are not fused together, but consist of flexible individual fibers lying loosely next to each other, which are strictly geometrically arranged and firmly enclosed on the input and output side (fiber bundles).
Instead of conventional imaging with optical lenses or mirrors, fiber optics are used wherever small dimensions and / or high light intensity are required: Compared to 1: 1 optics with aperture 1, the light intensity is approx. 10 times higher (with diffuse Lambert -Lighting). For example, with intubation fiber optics to display the larynx for endotracheal intubation.
The transmitted image is resolved pixel by pixel . There are two common arrangements of the pixels: hexagonal or orthogonal . The distance between the individual pixels is typically 4–10 µm. As with a light guide, each individual fiber consists of a core glass and an enveloping low- refractive cladding glass . In between strands of black ( absorbing ) glass are also arranged to hold back stray light .
If the resulting cylindrical block is heated and pulled again after fusing, it tapers in the middle and can be separated at the resulting waist: In this way, a taper , i.e. fiber optics, can be used for a reduction that deviates from the 1: 1 scale or enlargement.
Similar to imaging with a lens, however , the brightness remains constant when the image is reduced, regardless of the image scale. This means that part of the incident light intensity is lost on the way from the entrance to the exit area, otherwise the luminance would be higher on the smaller exit side. This loss occurs because, due to the multiple reflection , some of the light rays in the conically tapered individual fibers exceed the critical angle of total reflection and are therefore not passed on.
If the glass block is twisted instead of pulled when it is heated again, a twister is created . This is mostly used with 180 ° torsion for image reversal.
Fused fiber optics are often used in image intensifiers in order to be able to easily and reliably forward (= couple) the screen image to downstream image sensors, for example to CCDs .
Individual evidence
- ↑ DIN 58140-1. Fiber optics - Part 1: Terms, symbols . February 2020.
- ↑ Pedrotti, Frank L., 1932-: Optics for engineers: Fundamentals; with 28 tables . 3rd, edited and updated edition. Springer, Berlin Heidelberg New York 2005, ISBN 3-540-27379-4 , 24. Fiber optics.
- ↑ Erik Theiss: Lighting technology: new technologies for indoor and outdoor lighting . tape 1 . Oldenbourg-Industrieverl., Munich 2000, ISBN 3-486-27013-3 , p. 84 ff .