“…Comprised of a quartz cube with an integral fiber pigtail, it provided a simple means of actively aligning the InGaAs/ InP photodiode with the fiber core to give very high coupling efficiency, while the lower dielectric constant of quartz reduced the stray capacitance [62]. With the total input capacitance reduced to less than 0.5 pF, p-i-n FET hybrid -receivers were able to demonstrate better sensitivities at up to 565 Mbit/s than the Ge APD's then available [29], [63], with very little variation with temperature. These early p-i-n FET hybrids used a FET/bipolar cascode preamplifier which provided a -3-dB bandwidth of 350 MHz.…”