Should I choose Silicon or Germanium?
The choice of detector is affected by several parameters: beam size, power and wavelength. In general a photodiode will give best results when used at wavelengths below the wavelength of peak sensitivity. Although the head may operate at higher wavelengths, the sensitivity of the photodiode will be strongly temperature dependant. Thus, for wavelengths beyond 950nm, germanium will be the material of choice.
At wavelengths below 800nm, silicon exhibits markedly higher responsivity than germanium.
The photosensitive area of our Si and Ge fibre receptacle detector heads are very similar, the silicon detector being slightly larger.