All-optical inverter operating at 1.53 mu m laser in erbium yttrium aluminum garnets

An all-optical inverter derived from the negative nonlinear absorption effe ct was demonstrated in erbium-yttrium aluminum garnet crystals using 1.53 m u m laser diode. The effect was obtained at wavelengths of 1532 to 1534 nm in absorption spectra corresponding to the transition from the I-4(15/2) to the I-4(13/2) levels in Er3+ for sample lengths greater than 1.0 mm. The r eversed-phase transmitted wave forms were observed at modulation frequencie s from 1 kHz to 1 GHz. The negative nonlinear absorption effect can be expl ained by considering an enhanced absorption model for a four-level system o f the Er3+ ion. (C) 1999 American Institute of Physics. [S0003-6951(99)0031 2-5].