Jds Uniphase Corporation

Greg Roth

Steven Sanders

Stuart MacCormack

Erji Mao

The present application relates to a Raman amplifier having an increased dynamic range, and particularly for laser pump sources and a method of pumping Raman fiber amplifiers over a greater dynamic range. In a multi-channel optical system, optical amplifiers must be able to provide gains over a large dynamic range, which is determined by the distribution of node-to-node distances in the network, as well as the number of channels. The present invention has found that the dynamic range of a Raman amplifier can be significantly increased by using pulse width modulation to pulse pump current at or near the minimum current stability threshold, in order to produce lower power output. The duty cycle of the pulsed current is selected to achieve a time-averaged operating condition, thus the time averaged pump power can be reduced in a linear fashion well below the capability of a continuous wave system.

Wider dynamic range to a FBG stabilized pump

The invention relates to a method for automatic dynamic gain control in optical Raman amplifiers and an optical Raman amplifier adapted for the same. The present invention has found that in multiple pump Raman amplifiers a substantially linear relationship exists between total amplified signal power and pump power for each of different wavelength pumps, in order to maintain an original gain profile and gain levels for an optical link with a fully loaded channel configuration, in response to dropped channels. In accordance with the method, and an amplifier programmed to practice the method, a set of pump power values and signal level values required to maintain the characterized gain profile and gain levels for a plurality of channel loading configurations are pre-established for the each pump wavelength. A linear function from each set of pre-established values is derived for each pump wavelength. Advantageously, a single photodiode can replace a costly and complex channel monitor for providing signal responsive pump control.

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Santa Ana, CA, United States of America

Greg Roth