On-chip erbium-doped lithium niobate microcavity laser and spiral waveguide amplifier

Integrated optical amplifiers and light sources are of great significance for photonic integrated circuits (PICs) and have attracted many research interests. Doping rare-earth ions in materials as a solution to realize efficient optical amplifiers and lasing has been investigated a lot. We investigated the erbium-doped lithium niobate on insulator (LNOI). Here, we fabricated a 1-mol% erbium-doped LNOI microdisk with a high-quality factor. C-band laser emission at ∼1530 and ∼1560 nm (linewidth 0.12 nm) from the high-Q erbium-doped LNOI microdisk was demonstrated with 974- and 1460-nm pumping. What’s more, spiral waveguide amplifiers were also fabricated by the CMOS-compatible technique. A maximum internal net gain of 8.3 dB at 1530 nm indicating a net gain per unit length of 15.6 dB/cm with a compact spiral waveguide of 5.3 mm length and ~0.06 mm2 footprint was demonstrated.