Multi-ring resonator implementation of optical spectrum reshaper for chirp managed laser technology

1. A method for transmitting an optical signal through a fiber comprising:

producing a frequency modulated signal;

passing the frequency modulated signal through a multi-ring resonator optical spectrum reshaper (OSR) so as to convert the frequency modulated signal into a substantially amplitude modulated signal, the operating point of the frequency modulated signal being near the edge of the transmission peak of the multi-ring resonator OSR; and

passing the substantially amplitude modulated signal into the fiber.

2. The method of claim 1 , wherein producing a frequency modulated signal comprises generating a frequency modulated signal having a bit rate and wherein the multi-ring resonator OSR has a transmission profile having a 3 dB bandwidth approximately equal to from 65% to approximately 90% of the bit rate.

3. The method of claim 1 , further comprising:

measuring a first optical power of the frequency modulated signal input to the multi-ring resonator OSR;

measuring a second optical power of signals transmitted from the multi-ring resonator OSR to the multi-ring resonator with the optical power of the transmitted signals from multi-ring resonator;

comparing the first and second optical powers; and

adjusting the frequency modulated signal to maintain the ratio of the first and second optical powers substantially constant.

4. The method of claim 3 , wherein measuring the first optical power comprises receiving at a first photodiode an output of a first tap coupled to an input of the multi-ring resonator OSR; and wherein measuring the second optical power comprises receiving at a second photodiode an output from a second tap coupled to an output through port of the multi-ring resonator OSR.

5. The method of claim 4 , wherein the first and second taps are integrated on the same substrate as the multi-ring resonator.

6. The method of claim 3 , wherein measuring the first optical power comprises receiving at a first photodiode an output of a first tap coupled to an input of the multi-ring resonator OSR; and wherein measuring the second optical power comprises receiving at a second photodiode an output from a second tap coupled to a drop port of the multi-ring resonator OSR.

7. The method of claim 1 , wherein the multi-ring resonator OSR comprises coupled straight sections and ring waveguides.

8. The method of claim 7 , wherein the number, the radii of the rings and the coupling between the rings is adjusted to produce a desired transmission profile.

9. The method of claim 1 , wherein the multi-ring resonator OSR has a transmission function that is a periodic function with a periodicity equal to an integer multiple of 50 GHz.

10. The method of claim 1 , wherein the multi-ring resonator OSR has a transmission function that is substantially Gaussian near each transmission peak.

11. The method of claim 10 , wherein the transmission function of the multi-ring resonator OSR is substantially flat-topped near each transmission peak.

12. The method of claim 1 , wherein the multi-ring resonator has a transmission function having of a slope of <0.2 dB/GHz near a transmission peak thereof

13. A fiber optic system according to claim 1 , wherein the peak slope of the transmission profile is approximately 2 dB/GHz to approximately 3 dB/GHz.

14. The method of claim 1 , wherein the multi-ring resonator has a transmission function having a slope of slope of approximately 0.36 dB/GHz 2 to approximately 0.6 dB/GHz 2 .

15. The method of claim 1 , wherein producing a frequency modulated signal comprises modulating a distributed feedback (DFB) laser.

16. The method of claim 2 , further comprising forming the DFB laser is integrated and the multi-ring resonator OSR on the same substrate.

17. The method of claim 1 , wherein producing a frequency modulated signal comprises modulating a distributed feedback (DFB) array.