what is the physics principle behind fiber optics
Snell's Law
critical angle
http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/fibopt.html
The basic functional structure of an optical fiber consists of an outer protective cladding and an inner core through which light pulses travel. The overall diameter of the fiber is about 125 μm and that of the core is just about 50 μm. The difference in refractive index of the cladding and the core allows total internal reflection in the same way as happens at an air-water surface show in . If light is incident on a cable end with an angle of incidence greater than the critical angle then the light will remain trapped inside the glass strand. In this way, light travels very quickly down the length of the cable over a very long distance (tens of kilometers). Optical fibers are commonly used in telecommunications, because information can be transported over long distances, with minimal loss of data. Another common use can be found in medicine in endoscopes. The field of applied science and engineering concerned with the design and application of optical fibers are called fiber optics.
The principle behind fiber optics is based on a branch of physics called Optics. Specifically, the principle involved is Total Internal Reflection. When light travels from one medium to another, it can experience reflection, refraction, or both. In the case of fiber optics, total internal reflection occurs.
Here are the step-by-step details of the physics principle behind fiber optics:
1. Total Internal Reflection: When light travels from a medium with a higher refractive index to a medium with a lower refractive index, it can undergo total internal reflection if the angle of incidence exceeds a certain critical angle. This critical angle is determined by the refractive indices of the two media involved.
2. Fiber Optic Cable Structure: A fiber optic cable consists of a core made of a high refractive index material surrounded by a cladding material with a lower refractive index. This difference in refractive indices allows total internal reflection to occur.
3. Light Propagation: When light is introduced into the fiber optic cable, it enters the core at an angle that is less than the critical angle. The light wave then undergoes multiple reflections off the boundary between the core and cladding.
4. Total Internal Reflection Occurs: As the light wave undergoes multiple internal reflections, it continues to bounce off the core-cladding boundary due to total internal reflection. This prevents the light from escaping the fiber optic cable and enables it to travel long distances without significant loss of signal strength.
5. Maintenance of Signal Integrity: The fiber optic cable structure is designed to ensure that the light waves maintain their coherence and direction throughout the transmission. This is achieved by using a material with a high refractive index for the core and a material with a low refractive index for the cladding.
6. Signal Extraction: At the receiving end of the fiber optic cable, the light undergoes a process of demodulation or detection, where it is converted back into its original form, such as data or an image, for further use.
Overall, the physics principle behind fiber optics is based on the phenomenon of total internal reflection, which allows light to propagate through the fiber optic cable with minimum signal loss, making it an efficient means of transmitting information over long distances.
The physics principle behind fiber optics is called total internal reflection. Total internal reflection occurs when a beam of light traveling through a medium, such as glass or plastic, encounters the boundary with another medium at a certain angle known as the critical angle.
In fiber optics, a thin strand of glass or plastic, called an optical fiber, is used to transmit light signals over long distances. The optical fiber consists of a core, which is the innermost part through which light travels, and a cladding, which surrounds the core. The core has a higher refractive index than the cladding, which is a measure of how much the light slows down when passing through a material.
When light enters the core of the fiber optic at an angle greater than the critical angle, it undergoes total internal reflection. This means that instead of passing through the boundary and escaping, the light is reflected back into the core, bouncing along the fiber with minimal loss of intensity or energy.
This principle allows light signals to be transmitted through the fiber optic cable by bouncing off the inner surfaces of the core. The light remains inside the core and travels through the fiber, even when it encounters bends or twists in the cable. At the end of the fiber, the light can be detected and converted into electrical signals.
To summarize, the physics principle behind fiber optics is total internal reflection, which allows light to bounce within the core of the optical fiber and transmit signals over long distances without significant loss.