Integrated circuits in optical receivers
View Patent ↗A circuit may include a photodiode configured to receive an optical signal and convert the optical signal to a current signal. The circuit may also include a transimpedance amplifier coupled to the photodiode and configured to convert the current signal to a voltage signal. The circuit may also include an equalizer coupled to the transimpedance amplifier and configured to equalize the voltage signal to at least partially compensate for a loss of a high frequency component of the optical signal. The equalizer and the transimpedance amplifier may be housed within a single integrated circuit.
1. A circuit comprising:
a photodiode configured to receive an optical signal and to convert the optical signal to a current signal;
a transimpedance amplifier coupled to the photodiode and configured to convert the current signal to a voltage signal; and
an equalizer coupled to the transimpedance amplifier, the equalizer comprising:
a static portion configured to provide constant equalization of the voltage signal; and
an adjustable portion configured to provide adjustable equalization of the voltage signal, such that the equalizer is configured to equalize the voltage signal to at least partially compensate for a loss of a high frequency component of the optical signal, the equalizer and the transimpedance amplifier being housed within a single integrated circuit.
2. The circuit of claim 1 , further comprising a driver coupled to the equalizer, the driver configured to drive the equalized voltage signal and being housed within the single integrated circuit.
3. The circuit of claim 2 , wherein the driver comprises a non-linear driver.
4. The circuit of claim 2 , wherein the driver is configured to drive the equalized voltage signal to a clock and data recovery circuit in another integrated circuit separate from the single integrated circuit.
5. The circuit of claim 1 , wherein the voltage signal comprises a pair of differential voltage signals.
6. An integrated circuit comprising:
an input configured to receive a current signal from a photodiode, the current signal representative of an optical signal received by the photodiode;
a transimpedance amplifier coupled to the input and configured to convert the current signal to a voltage signal;
an equalizer coupled to the transimpedance amplifier, the equalizer comprising:
a static portion configured to provide constant equalization of the voltage signal; and
an adjustable portion configured to provide adjustable equalization of the voltage signal, such that the equalizer is configured to equalize the voltage signal to at least partially compensate for a loss of a high frequency component of the optical signal; and
a driver configured to drive the equalized voltage signal from the integrated circuit to another integrated circuit.
7. The integrated circuit of claim 6 , wherein the static portion of the equalizer comprises an analog equalizer.
8. The integrated circuit of claim 6 , wherein the adjustable portion of the equalizer comprises a digital equalizer.
9. The integrated circuit of claim 6 , wherein the driver comprises a non-linear driver.
10. The integrated circuit of claim 9 , wherein the transimpedance amplifier has a substantially linear frequency response.
11. The integrated circuit of claim 6 , wherein the optical signal is generated by a transmitter, the transmitter comprising a transmitting equalizer.
12. The integrated circuit of claim 6 , wherein the voltage signal comprises a pair of differential voltage signals.