Occasionally known as 'Gain Flatness', this is a measure
of how much an amplifier
varies with the wavelength
signal. It is usually expressed in terms of dB
or in photonics
One of the characteristics of a 'perfect' amplifier is that it has a totally flat gain tilt (ie 0 decibels) across all wavelengths. No one has (as of yet) managed to create this mythical piece of hardware, and so the gain tilt of an amplifier is one of the primary determining factors of its useful operating bandwidth.