Patent ID: 7470884

Claim:
An optoelectronic transceiver, comprising: a laser; a photodetector configured to receive an optical signal and generate a corresponding electrical signal; a first stage circuit integrated into a TO package with the photodetector, the first stage circuit being configured to receive the electrical signal generated by the photodetector and to convert the received electrical signal to a differential output; and a second stage circuit in communication with the first stage circuit and configured to derive an optical signal strength of the optical signal based upon a signal strength 2MΔ′ of the differential output of the first stage circuit, where “M” is an amplification factor associated with the first stage circuit, and “2Δ′” is a signal strength of the differential output from the photodetector, wherein the second stage circuit derives the optical signal strength using a combination of bipolar junction transistors and field effect transistors, the second stage circuit comprising: a voltage-to-current converter; a first current regulator; a second current regulator; and a current-to-voltage converter, where the voltage-to-current converter, first current regulator, second current regulator, and current-to-voltage converter, respectively, are configured and arranged to operate as follows: the voltage-to-current converter is configured to: receive first and second voltages from the differential output of the first stage circuit; convert a difference between the first and second voltages to a first current; draw a second current from the first current regulator substantially equal to a sum of a first current offset and the first current; and draw a third current from the second current regulator substantially equal to a difference between a second current offset and the first current; the first current regulator is configured to: produce at least a first regulated amount of current; and produce a fourth current that flows to the current-to-voltage converter when the first regulated amount of current exceeds the second current, the fourth current substantially equal to a difference between the second current and the first regulated amount of current; the second current regulator is configured to: produce at least a second regulated amount of current; and produce a fifth current that flows to the current-to-voltage converter when the second regulated amount of current exceeds the third current, the fifth current substantially equal to a difference between the third current and the second regulated amount of current; and the current-to-voltage converter is configured to: convert the fourth current to a third voltage; and convert the fifth current to a fourth voltage, the fourth voltage and the third voltage being proportional to the difference between the first and second voltages.