A programmable amplifier 100 operable to independently adjust the amplification
given to various optical signals passing through an optical fiber. An input optical
fiber 102 provides a number of optical signals to a demultiplexer which
separates each signal carried by the input fiber 102. Each individual wavelength
travels to a variable attenuator 106 which lowers the signal strength of
each signal based on an input from the system controller 108. The attenuated
signals are combined by multiplexer 112 and input to an optical amplifier
114. The optical amplifier 114 receives the combined signal and amplifies
each signal in the combined DWDM signal across the entire bandwidth of the amplifier
114. The amplified signals are input to a splitter 116 which removes
a small portion of the entire spectrum output by the amplifier 114. The
remaining portion of the signal passes to an output fiber 110 and travels
to the remainder of the optical network. The small portion of the signal separated
by the splitter 116 is input to a spectrum analyzer 118 which detects
the signal strength of each component signal traveling through the optical amplifier
100. Signal strength information is passed to the system controller 108.
The system controller 108, typically a digital signal processor or programmable
microcontroller, uses the information from the spectrum analyzer 118 to
control the variable attenuators and the gain of amplifier 114 in order
to level the various signals traveling through the amplifier 100.
