Optical amplification in Er/Yb silicate slot waveguide

Active slot waveguides were fabricated by embedding low-index Er/Yb silicate material in high-index silicon. A 1.7 dB signal enhancement at 1.53 μm in a 6 mm-long slot waveguide was observed through 1476 nm pumping. The peak Er emission cross-section is determined as 7.53 × 10−21 cm2 and the excited Er ion fraction is 0.17. Our experi-ment shows that the defects in upper c–Si of Si-on-insulator (SOI) and deposited α–Si distorts photoluminescence spectrum and prevents further optical amplification. This negative effect can be partly corrected through annealing treatment, which allows better propagation of the pump light, therefore, stronger excitation in the sandwiched Er/Yb silicate. The defects also affect the 1.53 μm decay curve and are the dominant lifetime reduction mechanism in the active slot waveguide. © 2012 Optical Society of America OCIS codes: 230.4480, 160.5690, 230.7370. Over the last few years, slot waveguides have attracted increasing attention in the photonics community [1–5]. In this structure, low-index material is sandwiched by high-index silicon to form high-index-contrast configuration. Due to the continuity of normal electric displacement (D εE) at dielectric interface, the electric field for