Saturated small-signal gain of Si quantum dots embedded in SiO2/SiOx/SiO2 strip-loaded waveguide amplifier made on quartz

A SiO2/SiOx/SiO2 strip-loaded waveguide with buried Si quantum dots is optically pumped to provide amplified spontaneous emission centered at 805 nm with spectral linewidth of 140 nm. By top-pumping the 350-nm-thick SiOx with He-Cd laser of 40 mW at 325 nm, the optical gain of 65 cm(-1) and loss coefficient of 5 cm(-1) are determined. Under a 785 nm small-signal injection diagnosis, the power-dependent gain curve fitting with gain-saturated amplifier model reveals a peak gain of 27 dB (not including waveguide loss) and a net power gain of 9.5 dB for the Si-rich SiOx waveguide amplifier with a length of 5 mm.