E-band widely tunable, narrow linewidth heterogeneous laser on silicon

We demonstrate a heterogeneously integrated laser on silicon exhibiting a sub-20 kHz Lorentzian linewidth over a wavelength tuning range of 58 nm from 1350 to 1408 nm, which are record values to date for E-band integrated lasers in the literature. Wide wavelength tuning is achieved with an integrated Si ring-resonator-based Vernier mirror, which also significantly reduces the Lorentzian linewidth. Such a record performance leverages a mature heterogeneous III–V/Si platform and marks an important milestone in E-band optical fiber communications and in reaching visible wavelengths via second harmonic generation for optical atomic clock applications.