Avalanche Photodiodes
Low-Light and High-Gain Applications
GPD offers two avalanche photodiode (APD) options designed for high-sensitivity detection in low-light environments: InGaAs avalanche photodiodes and germanium avalanche photodiodes. Both types use internal gain to amplify weak optical signals. InGaAs APDs are optimized for high-performance detection in the near-infrared, while germanium avalanche devices provide a cost-effective solution for longer-wavelength detection that requires high gain.
InGaAs Avalanche Photodiodes (APDs)
InGaAs avalanche photodiodes are used when greater sensitivity is needed than standard photodiodes can provide. These devices employ an internal gain mechanism in which impact ionization generates secondary electrons, triggering an electron avalanche that amplifies the original optical signal. This internal amplification enables reliable measurement of very weak signals. InGaAs APDs are commonly used in applications such as LiDAR, optical communications, and other systems where signal levels are extremely low.
Features
- Chip active diameters from 80 μm to 350 μm
- Spectral response from 900 nm to 1650 nm
- Linear operation
- Low dark current for high sensitivity
- Low capacitance for high speed
- Fiber pigtail available (single-mode or multi-mode)
- Package flexibility (TO packages and ceramic submounts, with ball lens option)
Applications
- LiDAR
- Free space optics
- High-sensitivity photometry
- Optical time domain reflectometer (OTDR)
- Optical communication
Germanium Avalanche Photodiodes
Germanium Avalanche Photodiodes are often used to measure optical power in the near-infrared range, particularly in cost-sensitive applications or where a large-area detector is required. Compared with similarly sized InGaAs detectors, germanium devices generally have lower shunt resistance and higher dark current, resulting in higher overall noise. As a result, they are best suited for applications where the detected signal is well above the noise floor. GPD Optoelectronics offers an “HS” series of germanium photodiodes with higher-than-typical shunt resistance to help improve performance.
Features
- Small Diameter (40µm)
- 800nm to 1800nm Spectral Response
- Linear and Geiger Mode Operation
- High Sensitivity
- Fiber Pigtail (Single or Multi Mode), including Hi-Reliability Pigtail
- Thermoelectric Cooling Available
- Packages (TO-46 and sub-mount)
Applications
- Optical Time Domain Reflectometer (OTDR)
- Optical Communications
- Photon Counting