NON-LINEAR OPTICAL AMPLIFICATION

摘要

An optical amplifier having a saturable absorption region is operated below the lasing threshold for the device. Non-linear effects and bistability are observable at temperatures above room temperature. A selected input wavelength lambda i within the gain spectrum of the device is amplified and an output at the same wavelength lambda i is produced. This is in contrast to the normal operation at threshold, where there is a wavelength shift to the lasing wavelength and, depending on the laser used for the naturable absorption device, the output may be multimode for a monomode input. Best gain is achieved by tuning the input wavelength to a peak of a Fabry-Perot mode in the gain spectrum for the amplifier. The amplifier may be used as wavelength controlled optical switch, when operated bistably, or as a regenerative amplifier when operated in the non-linear region without hysteresis effects.