Large‐ and small‐signal gain characteristics of 1.5 μm multiple quantum well optical amplifiers

We report large‐ and small‐signal gain characteristics of 1.5 μm multiple quantum well optical amplifiers. We demonstrate a 350‐μm‐long amplifier with a peak gain of 15 dB. At a wavelength where the small‐signal gain is 13.5 dB, the 3 dB saturation output power is as large as 45 mW. The 3 dB saturation output energy is 5.1 pJ and the calculated gain recovery time is 57 ps. We also demonstrate a 625‐μm‐long device with a gain of 19 dB and a saturation output power of 42 mW.