Optical sources and detectors ppt

Light sources and light detectors. Tungsten, Deuterium, Mercury, Hollow Cathode Lamp. Power emanating from the light . as Word Doc (.doc), PDF File (. pdf), Text File (.txt) or read online for free.

For APD detectors with gain the effect of the multiplied noise during the “0” is more severe, this case is shown in the graph to the left.

Characteristics of light sources.

To couple large amounts of power, size and configuration of sources should be compatible with an optical fiber Must accurately track the electrical signal to minimize distortion and noise Source should emit light at wavelengths where the fiber has low loss, low dispersion, and detectors are .

Optical units, radiometry and photometry. The normally empty conduction band of the semiconductor is populated by electrons injected into it by the forward current through the junction, and light is generated when these electrons recombine with holes in the valence band . The optical fiber communication . For optical fiber communication, major light sources are hetero-junction- structured semiconductor laser diode and light emitting diodes. OPTICAL FIBER OFC have Fibres which are long, thin strands . Should emit light at wavelengths where the fiber has low losses and low dispersion and where the detectors are efficient.

Inverse device with semiconductor lasers Source : convert electric current to optical power Detector : convert optical power to electrical current Use pin structures similar to lasers Electrical power is proportional to iElectrical power is proportional to optical power squared Called square law device Important characteristics . Requirements for an optical source for optical communications. Suitable size and configuration compatible with launching light into an optical fiber (highly directional output). Two basic light sources are used for fiber optics: lasers and light-emitting diodes (LED). Each device has its own advantages and disadvantages as listed in Table.

You will learn about the different types of fiber and their applications, light sources and detectors , couplers, splitters, wavelength- division multiplexers, and state-of-the-art devices used in the latest high- bandwidth . Response time: Is the time delay . A size and configuration compatible with launching light into an optical fiber. Ideally, the light output should be highly directional. The source should be linear ( to track the electrical signal).

In optical communications, light sources must be compact, monochromatic,. This type of light source requires an external modulator at its optical output. In this arrangement, an electrical signal representing a. This presentation covers: Concepts of optical fiber communication in detail Total internal reflection inter-modulation, dispersion effects in OFC.