Apd Photodiode

October 30, 2024 Post a Comment

Apd photodiode

An avalanche photodiode (APD) is a highly sensitive semiconductor photodiode detector that exploits the photoelectric effect to convert light into electricity. From a functional standpoint, they can be regarded as the semiconductor analog of photomultiplier tubes.

What are difference between PIN and APD photodiodes?

They are high-sensitivity, high-speed semiconductor light sensors. The main advantage of the APD is that it has a greater level of sensitivity compared to PIN. The avalanche action increases the gain of the diode many times, providing much higher sensitivity. However, an APD requires a higher operating voltage.

How does an avalanche photodiode work?

Avalanche photodiodes operate in reverse bias at a voltage near to the breakdown voltage. Thus, a large number of electron-hole pairs are produced for one incident photon in the depletion region (internal ionisation). Schottky photodiodes use electrons freed by incident light at a metal-semiconductor junction.

What is PIN and APD photodetector?

PIN photodiode is a kind of photo detector, it can convert optical signals into electrical signals. This technology was invented in the latest of 1950's. There are three regions in this type of diode. There is a p-region an intrinsic region and an n-region.

What are the disadvantages of APD?

Avalanche photodiode disadvantages: Much higher operating voltage may be required. Avalanche photodiode produces a much higher level of noise than a PN photodiode. Avalanche process means that the output is not linear.

What are the advantages of APD over other types?

The advantages that APDs can offer over the conventional photomultiplier tubes are the high quantum efficiency of semiconductors, smaller dimensions, lower operating voltage, and lower sensitivity to magnetic fields often encountered in high-energy physics research.

Why does APD need a higher bias voltage?

Increasing the bias will improve sensitivity and reduce bit error in the receiver when the incident power is very low; reducing the bias will protect the APD from damage in high-temperature conditions or when the receive power is very large.

What is the advantage of PIN photodiode?

Advantages of PIN diode : Low bias voltage. Higher reverse voltages to be tolerated. High-speed response. Low junction capacitance.

What are the applications of PIN photodiode?

Applications of PIN Diode They are used in Photodetectors and photovoltaic cells, and the PIN photodiodes are used for fibre optic network cards and switches. These diodes are effectively used for RF protection circuits, and they can also be utilized as an RF switch.

Why it is called avalanche photodiode?

Avalanche photodiodes are named that for a reason: The term avalanche refers to the internal APD gain – the so-called avalanche breakdown. In standard diodes, impinging photons generate electron-hole pairs. These hole pairs provide a measurable photocurrent.

Why is it called reach through APD?

Hence for minimum noise, the electric field at avalanche breakdown must be as low as possible and the impact ionization should be initiated by electrons. iii. To this end a 'reach through 'structure has been implemented with the silicon APD. Hence called reach through APD.

What is avalanche breakdown in APD?

Avalanche breakdown takes place when the diode is subjected to high reverse voltage. The reverse bias voltage increases the electric field across the depletion layer. Incident light enters the p+ region and further gets absorbed in the highly resistive p region.

What are types of photodetectors?

Semiconductor-based photodetectors typically photo detector have a p–n junction that converts light photons into current. The absorbed photons make electron–hole pairs in the depletion region. Photodiodes and photo transistors are a few examples of photo detectors.

What are the types of photodiode?

Photodiode Types 1) PN photodiodes 2) PIN photodiodes 3) Schottky type photodiodes 4) Avalanche photodiodes All of these types provide the following features and are widely used for the detection of the existence, intensity, position and color of light.

How do photodetectors work?

Photodetectors measure photon flux or optical power by converting the absorbed photon energy into electrical current.

How does APD internally multiplies the current?

The APD (avalanche photodiode) is a high-speed, high-sensitivity photodiode that internally multiplies photocurrent when reverse voltage is applied. The internal multiplication function referred to as avalanche multiplication features high photosensitivity that enables measurement of low-level light signals.

Which photodiode is used for a low power optical signal and why?

Semiconductor photodiodes are the most commonly used detectors in optical fiber systems since they provide good performance, being small in size, and are of low cost. Semiconductor photodiodes are made of silicon, germanium, GaAs, InGaAs, etc.

What is photoelectric diode?

A photodiode is a PN-junction diode that consumes light energy to produce an electric current. They are also called a photo-detector, a light detector, and a photo-sensor. Photodiodes are designed to work in reverse bias condition.

What is quantum efficiency of photodiode?

A photodiode's capability to convert light energy to electrical energy, expressed as a percentage, is its Quantum Efficiency, (Q.E.). . It is expressed as the absolute responsivity in amps per watt. Please note that radiant energy is usually expressed as watts/cm^2 and that photodiode current as amps/cm^2.