Apparatus and method for recovering data at an optical receiver with automatic tuning
An optical receiver that recovers data is disclosed. The optical receiver includes a photodetector configured to convert an optical signal into a current signal, and a TIA (Transimpedance Amplifier) configured to operate according to a set of parameters to convert the current signal to a voltage signal. The optical receiver also includes an equalizer configured to process the voltage signal to produce a processed signal having recovered data from the optical signal, and to produce one or more equalization metrics. According to an embodiment of the disclosure, the optical receiver has a feedback processor configured to automatically tune operation of the TIA by adjusting at least one of the parameters of the TIA based on the one or more equalization metrics. This may effect a change in performance or power consumption of the optical receiver while receiving and recovering data. A corresponding method for recovering data is also disclosed.
1. An optical receiver, comprising:
a photodetector configured to receive an optical signal over an optical channel and to convert the optical signal into a current signal;
a TIA (Transimpedance Amplifier) configured to operate according to a set of parameters to convert the current signal to a voltage signal;
an equalizer configured to process the voltage signal to produce a processed signal having recovered data from the optical signal, and to produce at least one equalization metric; and
a feedback processor configured to automatically tune operation of the TIA by adjusting at least one of the parameters based on the at least one equalization metric to change the power consumption of the TIA, the at least one parameter comprising a power supply voltage supplied to the TIA.
2. The optical receiver of claim 1 , wherein the feedback processor is configured to automatically tune operation of the TIA continuously in real-time to effect changes in performance or power consumption of the optical receiver while recovering data.
3. The optical receiver of claim 2 , comprising:
a DSP (Digital Signal Processor) implementing at least the equalizer and the feedback processor;
wherein the feedback processor implements a search algorithm to determine how to adjust at least one of the parameters continuously in real-time to effect the changes in performance or power consumption of the optical receiver while recovering data.
4. The optical receiver of claim 1 , wherein the at least one equalization metric comprises one or more of an SNR (Signal to Noise Ratio) of the processed signal, an indication of equalization strength for the equalizer to recover data, an indication of tail strength of the processed signal, data framing information, DC-balance disparity information, a BER (Bit Error Rate) of the processed signal, residual ISI (Intersymbol Interference) of the voltage signal, or a THD (Total Harmonic Distortion) of the processed signal.
5. The optical receiver of claim 1 , wherein the feedback processor is further configured for adjusting at least one of the parameters to change a frequency response of the TIA.
6. The optical receiver of claim 5 , wherein the at least one parameter that is adjusted to change a frequency response of the TIA comprises impedance of an internal feedback circuit of the TIA.
7. The optical receiver of claim 5 , wherein the at least one parameter that is adjusted to change a frequency response of the TIA comprises impedance of an active or passive load of the TIA.
8. The optical receiver of claim 1 , wherein the feedback processor is further configured for adjusting at least one of the parameters to change an amplitude of the processed signal.
9. The optical receiver of claim 8 , wherein the at least one parameter that is adjusted to change an amplitude of the processed signal comprises a target output voltage of the TIA and/or a gain of the TIA.
10. The optical receiver of claim 1 , wherein the at least one parameter that is adjusted further comprises a bias current for the TIA.
11. The optical receiver of claim 1 , wherein the feedback processor is further configured for adjusting at least one of the parameters to change a THD (Total Harmonic Distortion) of the processed signal.
12. The optical receiver of claim 11 , wherein the at least one parameter that is adjusted to change a THD of the processed signal comprises a power supply voltage supplied to the TIA.
13. The optical receiver of claim 11 , wherein the at least one parameter that is adjusted to change a THD of the processed signal comprises a bias current for the TIA.
14. The optical receiver of claim 11 , wherein the at least one parameter that is adjusted to change a THD of the processed signal comprises a target output voltage of the TIA and/or a gain of the TIA.