Why avalanche photodiodes are more sensitive than regular PN junction photodiodes?
Their velocity will increase to such an extent that when they collide with the lattice, they will create further hole electron pairs and the process will repeat. The avalanche action enables the gain of the diode to be increased many times, providing a very much greater level of sensitivity.
In what applications are avalanche photodiodes most likely to be used?
Typical applications of avalanche photodiodes include receivers in optical fiber communications, range finding, imaging, high-speed laser scanners, laser microscopy, and optical-time domain reflectometers (OTDR).
What is the principle of avalanche photodiode?
An avalanche photodiode is a silicon-based semiconductor containing a pn junction consisting of a positively doped p region and a negatively doped n region sandwiching an area of neutral charge termed the depletion region.
What is the primary advantage of an avalanche photodiode?
Advantages of avalanche photodiode : Includes a greater level of sensitivity. High performance. Fast response time.
Why are photodiodes operated in reverse bias?
The photodiode is reverse biased for operating in the photoconductive mode. As the photodiode is in reverse bias the width of the depletion layer increases. This reduces the junction capacitance and thereby the response time. In effect, the reverse bias causes faster response times for the photodiode.
Which is better photodiode or phototransistor?
A phototransistor is more sensitive than a photodiode about one hundred times. Photodiodes pass less current compared to phototransistor while in photodiode consumes less current than a phototransistor. The dark current of the phototransistor is much higher than a photodiode.
In what applications are avalanche photodiodes APD most likely to be used quizlet?
In what applications are avalanche photodiodes (APD) most likely to be used? In fiber-to-the-home (FTTH) architectures where the high attenuation of optical splitters must be overcome. You just studied 8 terms!
What is sensitivity of APD?
APDs are photodiodes with internal gain produced by the application of a reverse voltage. They have a higher signal-to-noise ratio (SNR) than PIN photodiodes, as well as fast time response, low dark current, and high sensitivity. Spectral response range is typically within 200 – 1150 nm.
How does temperature affect the avalanche gain?
The avalanche gain, initiated by pure electron injection, was found to reduce with decreasing temperature. However no significant change in the excess noise was measured as the temperature was varied.
What do you understand by avalanche breakdown?
Avalanche breakdown (or “the avalanche effect”) is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow very large currents within materials which are otherwise good insulators. It is a type of electron avalanche.
Why are photodiodes operated in reverse bias condition?
A) When the diode is reverse biased, no ordinary current flows and the detection of the photo-current is much easier. When the diode is reverse biased, ordinary current flows and the detection of the photo-current is much easier. …
What do photodiodes do?
A photodiode is a semiconductor p-n junction device that converts light into an electrical current. The current is generated when photons are absorbed in the photodiode. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas.