On-chip ytterbium-doped lithium niobate waveguide amplifiers with high net internal gain

Integrated optical systems based on lithium niobate on insu-lator (LNOI) have shown great potential in recent years. However, the LNOI platform is facing a shortage of active devices. Considering the significant progress made in rare-earth-doped LNOI lasers and amplifiers, the fabrication of on-chip ytterbium-doped LNOI waveguide amplifiers based on electron-beam lithography and inductively cou-pled plasma reactive ion etching was investigated. The signal amplification at lower pump power (<1 mW) was achieved by the fabricated waveguide amplifiers. A net internal gain of similar to 18 dB/cm in the 1064 nm band was also achieved in the waveguide amplifiers under a pump power of 10 mW at 974 nm. This work proposes a new, to the best of our knowl-edge, active device for the LNOI integrated optical system. It may become an important basic component for lithium nio-bate thin-film integrated photonics in the future. (c) 2023 Optica Publishing Group