InGaAs PIN photodiodes have a smaller energy gap than Si photodiodes meaning that they are sensitive at longer wavelengths than Si devices. The energy gap can also be adjusted by varying the composition ratio of In and Ga extending performance further into the infrared.
A typical standard product is the IG17 with a peak wavelength of 1.7 microns, making it suitable for applications that cannot be met spectrally with a regular InGaAs photodiode; the detectors have active areas ranging in diameter from 0.25 to 3.00mm.
Responsivity can be improved dramatically by reducing the operating temperature of the device with a thermo electric cooler. The devices are manufactured in standard TO style packages and have long expected lifetimes making them suitable for fit and forget applications such as gas analysis, laser monitoring, moisture measurement and tuneable diode laser spectroscopy.