Full characterization of packaged Er-Yb-codoped phosphate glass waveguides

We present a procedure for the characterization of packaged Er-Yb-codoped phosphate glass waveguides. The procedure is based on precise measurements of the output optical powers when the waveguide is diode-laser pumped at 980 nm. The dependence of these optical powers on the input pump power is then fitted to the results from a numerical model that describes in detail the propagation of the optical powers inside the waveguide. The best fit is obtained for the following parameters: the signal wavelength scattering losses are α(1534)=8.3×10^-2 dB/cm, the Yb³⁺ absorption and emission cross sections (≈980 nm) are 5.4×10^-25 m² and 7.0×10^-25 m², the Er³⁺ absorption and emission cross sections (≈980 nm) are 1.6×10^-25 m² and 1.2×10^-25 m², the Yb³⁺--Er³⁺ energy-transfer coefficient is 1.8×10^-23 m³/s and the cooperative-upconversion coefficient is 8×10^-25 m³/s. An approximate method is introduced that allows the determination of the absorption and emission cross section distributions for the erbium ⁴I₁₃2/⇔⁴I₁₅2/ transition from the amplified spontaneous emission power spectrum.