speed and responsivity of the photodiode can be controlled. Note that Figure 2. Penetration depth (1/e) of light into silicon substrate for various wavelengths. BiCMOS-Integrated Photodiodes BiCMOS circuits enable the use of photodiode with a capacitance of pF, a -3dB bandwidth of MHz was reported. nm was estimated due to the lower penetration depth than for P guard-ring.