Dispersion compensation modules with fiber Bragg gratings
View Patent ↗A device used for dispersion compensation of a plurality of optical signals passing through an optical transmission line. The device includes a photosensitive optical fiber including a long length, chirped Bragg grating providing dispersion compensation over a wide bandwidth of optical signals. The long length chirped Bragg grating has a reflection bandwidth greater than about 25 nm, and further has reduced distortion at a bit rate of about 10 −9 . This reduced distortion leads to a power penalty of less than 3 dB during less than 25 nm stepwise changes in wavelength of the plurality of optical signals across the wide bandwidth. The device provides a dispersion greater than about 100 ps/nm in a optical transmission line operating at 10 Gbit/s.
1. A refractive index grating for dispersion compensation of a plurality of optical signals passing through an optical transmission line, said refractive index grating comprising:
a photosensitive optical fiber including a long length, chirped Bragg grating providing dispersion compensation over a wide bandwidth of said plurality of optical signals, said long length chirped Bragg grating having a reflection bandwidth and a weighted phase ripple amplitude wherein said reflection bandwidth has a full-width at half maximum that is greater than 25 nm, said weighted phase ripple amplitude being less than about 300 milliradians.
2. The refractive index grating of claim 1 , wherein said weighted phase ripple amplitude is less than about 200 milliradians.
3. The refractive index grating of claim 2 , wherein said weighted phase ripple amplitude is less than about 100 milliradians.
4. The refractive index grating of claim 1 , wherein said long length, chirped Bragg grating has a dispersion, measured in reflection, that is greater than 100 ps/nm.
5. The refractive index grating of claim 4 , wherein said long length, chirped Bragg grating has a dispersion, measured in reflection, that is greater than 400 ps/nm.
6. The refractive index grating of claim 4 , wherein said long length, chirped Bragg grating is a matched Bragg grating that substantially compensates the dispersion characteristics of the optical fiber transmission line.
7. The refractive index grating of claim 6 , wherein said matched Bragg grating has a parameter κ equal to the ratio of said dispersion and a dispersion slope characteristic of said matched Bragg grating over said wide bandwidth, said parameter κ substantially matching the optical fiber transmission line parameter κ.
8. The refractive index grating of claim 7 , wherein said parameter κ differs less than ±10% from the transmission line parameter κ.
9. The refractive index grating of claim 7 , wherein said parameter κ has a range from about 50 nm to about 300 nm.
10. The refractive index grating of claim 1 , wherein said long length, chirped Bragg grating has a length exceeding about three meters.