The increase of DWDM wavelength channel count has resulted in significant increases in power applied in telecommunication optical fibers. As higher powers and longer distances are required, there is a need for stronger fiber amplifiers. Here we present passive components for controlling the optical power in high power networks.
High power amplifiers are used to increase the signal power injected into the input port. The output signal is a function of the input signal (including spectral and temporal shape), as well as the operating conditions of the amplifying unit.
When the input signal is composed of many wavelength channels, each having its own power level, power management (or equalization) is required at the input port. When the channels are equalized, amplifiers are exploited most efficiently. Power unbalance due to non-equalized amplification of amplifiers causes degradations of signal to noise ratio.
Output ports of fiber amplifiers are sometimes susceptible to high power spikes. This can occur, for example, when the input to an operating amplifier is suddenly turned on. These spikes can be destructive to components and equipment on the network. Moreover, phenomena known as the ‘fiber fuse’ can destroy the fibers in a network due to over-power.
We introduce novel passive optical components, which can control and regulate the optical powers in the input to and at the output from a fiber amplifier. These components include power limiters that protect against excessive optical power transmission, and power equalizers. They can either replace or complement existing active power feedback control loops.
Power control components for high power networks will be described with emphasis on both their properties and their application in the network.