Push-pull optical receiver with cascode amplifiers

An optical receiver circuit for an optical signal having broadband radio frequency amplitude modulation, said circuit comprising:

• an optical detector having an input terminal and an output terminal, said optical detector operative for receiving said optical signal and for generating therefrom an electrical signal which varies with the power level of said optical signal;
• first amplifying means arranged in a cascode configuration for amplifying said electrical signal;
• second amplifying means arranged in a cascode configuration for amplifying said electrical signal;
• said first amplifying means and said second amplifying means each comprising:
• a transimpedance amplifier stage including a first field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being connected to said output terminal of said optical detector through a respective coupling capacitor, wherein the drain terminal of each first field effect transistor is connected to the gate terminal of the same first field effect transistor through a selectable feedback resistor;
• and
• a cascode stage including a second field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being coupled to a bias source, each of said drain terminals being coupled to a power source, and each of said source terminals being coupled to the drain terminal of said first field effect transistor of said transimpedance amplifier stage;
• and
• means for coupling said first amplifying means and said second amplifying means in a push-pull relationship.