InGaAs avalanche photodiode

The InGaAs Geiger-mode avalanche photodiode (APD) is a product specifically designed for single-photon counting applications. This device operates in "Geiger mode" by applying a voltage higher than the breakdown voltage, causing incident photons to generate a large current due to the substantial gain within the avalanche diode, effectively enabling the detection of single photons. When combined with matching external pulse detection circuits, it enables single-photon detection in the wavelength range of 0.95-1.65 micrometers.

The product is available in two packaging structures: T0 coaxial pigtail and integrated cryogenic butterfly, and can also be customized for specific customer application requirements.

Periodic poling is achieved through quasi-phase matching techniques, where an external electric field is applied to the lithium niobate crystal to periodically reverse the spontaneous polarization direction of the crystal's ferroelectric domains. This solves the phase mismatch problem, enabling frequency conversion for different wavelengths.

Based on periodically poled lithium niobate (PPLN) RPE waveguides, in the communication wavelength range of 1550nm, transmission losses can be reduced to as low as 0.1dB/cm, and coupling losses with optical fibers can be minimized to 0.5dB. These technical specifications have reached an international leading level.