The FD500 from Nortus Optronic GmbH is a Photodiode with Wavelength Range 1300 to 1550 nm, Capacitance 15 to 25 pF, Dark Current 8 to 15 nA, Responsivity/Photosensitivity 0.8 to 0.95 A/W, Active Area Diameter 500 µm. More details for FD500 can be seen below.
