Photonic-chip integrated large-mode-area high-power CW optical amplifier

Here, we report on a CMOS-compatible thulium-doped high power continuous wave (CW) optical amplifier, leveraging large mode-area gain waveguides. The amplifier structure combines a silicon nitride waveguide above which a sputtered 1250 nm-thick thulium-doped alumina gain layer is deposited. We demonstrate >220 mW output signal power at center wavelength of 1850 nm inside a 9-cm-long amplifier. Small signal gain of >15 dB is achieved.