Systems and methods for relative intensity noise cancelation

1. A noise cancelation system for optical communication, the system comprising:

a first slicer configured for generating first PAM symbols and error data based on a data stream;

a relative intensity noise (RIN) estimation module configured for generating RIN data based on the first PAM symbol and error data;

a filter for removing non-RIN information from RIN data and generate filtered data, the filtered data comprising an offset term and a gain term;

a first compensation module configured to compensate the data stream using the offset term;

a second compensation module configured to compensate the data stream using the gain term; and

a second slicer configured to generate second PAM symbols using the compensated data stream.

2. The system of claim 1 further comprising a feedforward equalizer (FFE) equalizing a converted data stream and generating the data stream.

3. The system of claim 2 further comprising an analog-to-digital converter (ADC) for converting an electrical signal to the converted data stream.

4. The system of claim 3 further comprising a transimpedance module for converting an optical signal to the electrical signal.

5. The system of claim 4 further comprising an optical receiver for receiving the optical signal.

6. The system of claim 4 further comprising an equalizer for processing the electrical signal.

7. The system of claim 1 wherein the filter comprises a low-pass filter.

8. The system of claim 1 wherein the filter comprises a leaky integrator.

9. The system of claim 1 wherein the error data is based on a difference between the data stream and the first PAM symbol.

10. The system of claim 1 wherein the non-RIN information includes a transimpedance noise.

11. An optical receiver apparatus comprising:

an optical interface for receiving optical signal via an optical communication link;

a transimpedance module for converting the optical signal to an electrical signal;

an analog-to-digital converter for converting the electrical signal to a digital data stream;

a digital signal processor (DSP) for removing relative intensity noise (RIN) from the data stream, the DSP is configured to:

generate first PAM symbols and first errors;

generate a RIN data based on the first PAM symbols and the first errors;

remove non-RIN information from the first errors to generate filtered data, the filtered data comprising an offset term and a gain term;

remove the offset term and the gain term from the data stream to generate a compensated data stream.

12. The apparatus of claim 11 where the DSP is further configured to generate second PAM symbols by processing the compensated data stream.

13. The apparatus of claim 11 further comprising a continuous time linear equalizer module for equalizing the electrical signal.

14. The apparatus of claim 11 wherein the DSP comprises a filter for removing the non-RIN information.

15. The apparatus of claim 11 further comprising a first slicer for generating the first PAM symbols.

16. The apparatus of claim 11 wherein the DSP is implemented using an application-specific integrated circuit (ASIC).

17. The apparatus of claim 11 wherein the DSP is implemented using a microprocessor.

18. A method for removing relative intensity noise, the method comprising:

converting optical signal to electrical signal;

converting electrical signal to data signal;

generating first PAM symbols and a first error data;

estimating a first RIN data based on the first PAM symbols and the first error data;

removing non-RIN information from the first RIN data to generate a second RIN data, the second RIN data includes an offset term and a gain term; and

generating second PAM symbols based on the data signal and the second RIN data.

19. The method of claim 18 further comprising equalizing the electrical signal.

20. The method of claim 18 further comprising equalizing the data signal.