lavinhalvledardioder

The lavinhalvledardioder, commonly known as the **avalanche photodiode** in English, is a specialized type of photodiode designed for high-sensitivity detection of light, particularly in low-light conditions. Unlike conventional photodiodes, which operate in the linear (or "proportional") mode, the avalanche photodiode exploits the avalanche breakdown phenomenon to achieve significantly higher internal gain.

In operation, an avalanche photodiode is reverse-biased beyond its breakdown voltage, causing incoming photons to generate electron-hole pairs. These carriers then undergo a chain reaction of impact ionization, producing additional charge carriers through collisions with the semiconductor lattice. This process amplifies the photocurrent, enabling detection of extremely weak light signals. The internal gain can reach values of 100 or more, depending on the bias voltage and device design.

Avalanche photodiodes are widely used in applications requiring high sensitivity, such as optical communication systems, laser rangefinders, and medical imaging. Their ability to detect faint signals makes them indispensable in fiber-optic networks, where signal attenuation over long distances necessitates precise detection. However, their use of high reverse bias voltages introduces noise, which can limit performance in some applications.

The device is typically fabricated from materials like silicon (Si) or indium gallium arsenide (InGaAs), with structures optimized for specific wavelengths of light. Variations include separate absorption and multiplication (SAM) regions, which improve response time and reduce noise. Despite their advantages, avalanche photodiodes require careful handling due to their sensitivity to reverse leakage current and the risk of permanent damage from excessive bias.

In summary, the lavinhalvledardioder combines high sensitivity with internal gain, making it a critical component in advanced optical detection systems.