Abstract: An optical transceiver with a transimpedance amplifier generates a dynamic common mode voltage of the peak-to-peak output current of the photodetector for use as an in-situ optical power meter. Peak-to-peak voltage signal are imposed on the common mode voltage so optical power measurements are obtained using preexisting electrical contacts. An nfet and a capacitor of the transimpedance amplifier smooths the peak-to-peak voltage to create the control signal for the common mode voltage. The common mode current is mirrored into a bank of pfets at the output stage to create a current sink. Depending upon the potential of the common mode voltage, more or less current will be drawn from the peak-to-peak voltage signals output from a final differential amplifier stage of the transimpedance amplifier.

Abstract: An optical transceiver having a transimpedance amplifier with an in-situ optical power meter is disclosed which realizes that the common mode voltage of a peak-to-peak voltage signal derived from impinging light is related to the optical power of the impinging light. The peak-to-peak voltage signals, moreover, can be imposed on the common mode voltage so that the optical power measurements can be derived with existing electrical contacts. In the preferred embodiment, the optical power meter takes advantage of certain functions within a transimpedance amplifier of the optical receiver. First, the use of an nfet and a capacitor smooth the peak-to-peak voltage to create the control signal for the common mode voltage. Then the common mode current is mirrored into a bank of pfets at the output stage to create a current sink.