Photodiode Calculator

Responsivity is the ratio of generated photocurrent to incident optical power, typically measured in A/W. It indicates how efficiently a photodiode converts light into electrical current in its linear response region.

Responsivity is directly proportional to quantum efficiency. It's calculated as R = η × (e/hν), where η is quantum efficiency, e is elementary charge, and hν is photon energy. Higher quantum efficiency means higher responsivity.

Responsivity depends on wavelength because photon energy varies inversely with wavelength (E = hc/λ). Different wavelengths have different absorption rates in the photodiode material, affecting quantum efficiency and overall responsivity.

Yes, photodetectors can have responsivity greater than 1 A/W, especially at longer wavelengths where photon energy is lower. Some avalanche photodiodes can achieve very high responsivity through internal gain mechanisms.

Responsivity measures the current output per unit optical power input (A/W), while sensitivity refers to the minimum detectable optical power. Responsivity is about conversion efficiency, sensitivity is about detection limits.

Quantum efficiency depends on wavelength, material properties, device structure, surface reflections, and absorption depth. Silicon photodiodes typically have highest efficiency in the 800-900 nm range.

Photocurrent equals responsivity multiplied by optical power: I = R × P. First calculate responsivity from wavelength and quantum efficiency, then multiply by the incident optical power to get photocurrent.

Silicon photodiodes work best in the 400-1100 nm range, with peak responsivity typically around 800-900 nm. Below 400 nm and above 1100 nm, responsivity drops significantly due to material limitations.