Observation of gain in an optically pumped surface-normal multiple-quantum-well optical amplifier

This is the authors' abstract. We don't add key points for this paper.

An optically pumped surface-normal optical amplifier with a 100-period InGaAs/InGaAlAs multiple quantum well is fabricated, and a signal gain exceeding 2 dB is observed for what we believe to be the first time. A laser diode with the wavelength lambda of 1.45 microm is used for pumping. An optical single-pass gain as high as 2.4 dB is obtained at lambda = 1.585 microm with 65-mW pumping (spot diameter 12 microm).