05050949 is referenced by 122 patents and cites 3 patents.

In this invention there is disclosed a multi-stage optical fiber amplifier for providing a new functon, that of gain equalization. The disclosed multi-stage optical fiber amplifier comprises at least two stages of amplification where each stage comprises an amplifying fiber having a different gain spectrum. In one embodiment the two stages, which can be pumped separately, have different dopant compositions to provide each stage with a different gain spectrum. The disclosed multi-stage optical fiber amplifier provides overall gain spectrum equalization of the amplified channels of long haul transmission lines. Typically, gain equalization can adjust the gain of one channel while maintaining the gain of a second channel constant. When used in combination with automatic gain control, the amplifier gain can be equalized dynamically to compensate for random variations in the relative optical power of wavelength-multiplexed signals to prevent system impairment caused by low-power channels.

Title
Multi-stage optical fiber amplifier
Application Number
7/542296
Publication Number
5050949
Application Date
June 22, 1990
Publication Date
September 24, 1991
Inventor
Clinton R Giles
Holmdel
NJ, US
David J DiGiovanni
Scotch Plains
NJ, US
Agent
Eli Weiss
Assignee
AT&T Bell Laboratories
NJ, US
IPC
G02B 6/26
View Original Source