Sputter-deposited neodymium-doped aluminium oxide for waveguide amplifiers in the O-band

The Al2O3 waveguide platform is an excellent candidate for monolithic and scalable fabrication of waveguide amplifiers. After successful demonstrations of sputter-deposited waveguides doped with Er3+, Yb3+ and Tm3+ ions, gain in the O-band is sought by means of Nd3+ ions, which form a four-level gain medium at a wavelength of 1330 nm. Preliminary results have shown on-chip gain of approximately 17 dB in a 7.52 cm long channel waveguide at 1064 nm. In this work, the optimization of Nd3+ doped Al2O3 optical waveguides to achieve net gain in the O-band is discussed.