Abstract: The present application relates to a doped fiber amplifier having an increased dynamic range, and particularly for laser pump sources and a method of pumping erbium doped fiber amplifiers over a greater dynamic range. In a multi-channel optical system, optical amplifiers must be able to provide gain over a larger range of signal powers, the dynamic range corresponding to the number of channels in the link. The present invention has found that the dynamic range of an EDFA 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 taking advantage of the relatively long relaxation time of the erbium. Thus the time averaged pump power can be reduced in a linear fashion well below the capability of a continuous wave system.

Abstract: The present application relates to a doped fiber amplifier having an increased dynamic range, and particularly for laser pump sources and a method of pumping erbium doped fiber amplifiers over a greater dynamic range. In a multi-channel optical system, optical amplifiers must be able to provide gain over a larger range of signal powers, the dynamic range corresponding to the number of channels in the link. The present invention has found that the dynamic range of an EDFA 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 taking advantage of the relatively long relaxation time of the erbium. Thus the time averaged pump power can be reduced in a linear fashion well below the capability of a continuous wave system.

Abstract: A wireless transmission and reception system includes a mixing section using a phase shift keying or quadrature amplitude modulation scheme to modulate a baseband signal, representing voice or data, onto a carrier frequency within the range of standard (cable television format) AM-VSB frequencies. A combiner section combines the modulated carrier signal into a channel of a multiplexed cable television (CATV) signal having two or more channels. The CATV signal is used to modulate a laser source. The laser source generates a laser signal based on the CATV signal. The laser signal is optically coupled into a bidirectional fiber link. The fiber link transmits the laser signal and ultimately converts the laser signal into the electrical CATV signal. A splitting section coupled to the bidirectional fiber link splits the modulated carrier signal from the CATV signal. A demodulating section coupled to the splitting section recovers the baseband signal from the modulated carrier signal.