K+ - Na+ ion-exchanged sodium magnesium aluminum germanate glass waveguide amplifier operating in the first telecommunications window

Potassium-sodium (K+ - Na+) ion-exchanged multimode channel waveguide amplifiers have been fabricated based on Tm3+ / Yb3+ codoped sodium magnesium aluminum germanate (NMAG) glass substrates. The normalized optical and relative gain coefficients of a 2.20 cm long device were identified to be 3.65 dB/cm and 1.58 dB/cm, respectively, at a signal wavelength of 810 nm under 457 mW 980 nm laser diode excitation. These are the highest values reported, and the results indicate that Tm3+ / Yb3+ codoped NMAG glasses are an attractive material for optical amplification in the first telecommunications window.