Telecommunication-wavelength lasing in a CMOS-compatible tilted-wave design

Light sources operating at the ∼1.5 μm telecommunication wavelength, based on erbium ions (Er³⁺) emission, are critical for on-chip optical communication in silicon photonic integrated circuits or chips (Si PICs). A waveguide-coupled laser termed tilted-wave laser (TWL) integrated with thin passive waveguide (<1 μm in thickness) is regarded as a promising on-chip light source for Si PICs due to its compatibility with the contemporary complementary metal-oxide-semiconductor (CMOS) planar technology. In this work, we report telecommunication-wavelength lasing of Er³⁺ in TW modes, using a high-performance Er³⁺-doped Si-rich oxide that exhibits a photoluminescence quantum yield (PLQY) of 20.6% and an optical net gain of 24.3 dB·cm^-1. The threshold optical pumping power for lasing is ∼40 mW. Edge-emitting photoluminescence (PL) of Er³⁺ is observed and consistent with the simulation results in TW modes. Light amplification of Er³⁺ along the waveguide is found remarkable. Other typical lasing characteristics are tested, including the threshold effects of PL intensity and spectral width versus input power, polarization effect, small spread of emission angle, and coherence property of the emitting light. The results of this work provide a viable solution and corresponding optimization pathway for developing CMOS-compatible light sources at telecommunication wavelengths.