DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click
HERE to register or log in.
Accession Number:
ADP007001
Title:
Nonlinear Effects in Semiconductor Optical Amplifiers,
Descriptive Note:
Corporate Author:
NIPPON TELEGRAPH AND TELEPHONE CORP TOKYO
Report Date:
1992-05-22
Pagination or Media Count:
4.0
Abstract:
A traveling-wave semi-conductor laser amplifier TWA 1-4 can greatly simplify optical repeaters used in wavelength-division-multiplexed WDM systems, since its wide gain bandwidth width allows a single TWA to simultaneously amplify signals of different wavelengths. Even though such system performance in the linear gain regime is determined only by amplifier noise properties 5,6, the onset of nonlinear effects in optical amplifiers result in crosstalk 7. Nonlinear effects in optical amplifiers have opposite aspects 1 unfavorable for linear amplifications where any nonlinearity impairs the performance and should be avoided, but 2 favorable for highly efficient nonlinear operation 8,9 due to a large optical gain compared with passiveabsorptive nonlinear materials. Two significant nonlinear effects are signal gain saturation 10 occurring for a large input signal and nearly degenerate four-wave mixing NDFWM 11,12 occurring for multifrequency input signals, as summarized in Fig. 1 13. The dominant nonlinearity in the semiconductor laser amplifiers SLAs restilts from changes in the injected-carrier density as a result of signal amplification. Signal gain saturation arises from the reduction in DC carrier component ndc, while the NDFWM is attributed to the generation of a carrier beat, component n omega at beat frequency omega.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
