Page 205 - Optical Communications Essentials

Optical Amplifiers

Optical Amplifiers 195

20 to 40km of transmission fiber. For this reason Raman amplification often is
referred to as distributed amplification. Pump lasers with high output powers
in the 1400- to 1500-nm region are required for Raman amplification of C- and
L-band signals. Lasers that provide fiber launch powers of up to 300mW are
available in standard 14-pin butterfly packages. To realize gain over a wide
spectral band, several pump lasers operating at different wavelengths normally
are used. These pumps are referred to popularly as 14XX-nm lasers. Tables 11.4
and 11.5 list the characteristics of couplers used to combine the pump powers and
to insert the aggregate pump output onto the fiber along with the C-band
and/or L-band transmission signals.

Further Reading
1. M. Young, “Next-generation networks may benefit from SOAs,” Laser Focus World, vol. 37,
pp. 73–79, September 2001.
2. J.-J. Bernard and M. Renaud, “Semiconductor optical amplifiers,” SPIE OE Magazine, vol. 1,
pp. 36–38, September 2001.
3. B. Verbeek, K. Vreeburg, H. Naus, W. van den Brink, L. Lunardi, and A. Turukhin, “SOAs
provide multiple network design options,” WDM Solutions, vol. 4, February 2002 (www.wdm-
solutions.com).
4. ITU-T Recommendation G.661, “Definition and Test Methods for the Relevant Generic
Parameters of Optical Amplifiers.”
5. ITU-T Recommendation G.662, “Generic Characterization of Optical Amplifier Devices and
Subsystems.”
6. ITU-T Recommendation G.663, “Application-Related Aspects of Optical Amplifier Devices and
Subsystems and Comprehensive Appendix on Transmission-Related Aspects.”
7. K. Wang, T. Strite, and B. Fidric, “Pump lasers at 960 nm for the L-band,” Lightwave, vol. 19,
pp. 72–76, March 2002 (www.lightwaveonline.com).
8. E. Desurvire, D. Bayart, B. Desthieux, and S. Bigo, Erbium-Doped Fiber Amplifiers: Devices and
System Developments, Wiley, New York, 2002.
9. J. Connolly, “New pump lasers power Raman amplifier,” WDM Solutions, vol. 3, pp. 57–62, June
2001 (www.wdm-solutions.com).
10. G. Keiser, Optical Fiber Communications, 3d ed., McGraw-Hill, Burr Ridge, Ill., 2000, Chap. 11.

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