We demonstrate a C-band wavelength-tunable microlaser with an E r 3 + -doped high quality ( ∼ 1.8 × 10 6 ) lithium niobate microdisk resonator. With a 976 nm continuous-wave pump laser, lasing action can be observed at a pump power threshold lower than 400 µW at room temperature. Furthermore, the microdisk laser wavelength can be tuned by varying the pump laser power, showing a tuning efficiency of ∼ − 17.03 p m / m W at low pump power below 13 mW, and 10.58 pm/mW at high pump power above 13 mW.

We demonstrate monolithic integration of an electro-optically (EO) tunable microring laser on lithium niobate on insulator (LNOI) platform. The device is fabricated by photolithography assisted chemo-mechanical etching, and the pump laser is evanescently coupled into the erbium ( E r 3 + )-doped lithium niobate (LN) microring laser using an undoped LN waveguide mounted above the microring. The quality factor of the LN microring resonator is measured as high as 1.54 × 1 0 5 at the wavelength of 1542 nm. Lasing action can be observed at a pump power threshold below 3.5 mW using a 980 nm continuous-wave pump laser. Finally, tuning of the laser wavelength is achieved by varying the electric voltage on the microelectrodes fabricated in the vicinity of a microring waveguide, showing an EO coefficient of 0.33 pm/V.

The escalating demands of compute-intensive applications urgently necessitate the adoption of optical interconnect technologies to overcome bottlenecks in scaling computing systems. This requires fully exploiting the inherent parallelism of light across scalable dimensions for data loading. Here we experimentally demonstrate a synergy of wavelength- and mode- multiplexing combined with high-order modulation formats to achieve multi-tens-of-terabits-per-second optical interconnects using foundry-compatible silicon photonic circuits. Implementing an edge-guided analog-and-digital optimization method that integrates high efficiency with fabrication robustness, we achieve the inverse design of mode multiplexers based on digital metamaterial waveguides. Furthermore, we employ a packaged five-mode multiplexing chip, achieving a single-wavelength interconnect capacity of 1.62 Tbit s⁻¹ and a record-setting multi-dimensional interconnect capacity of 38.2 Tbit s⁻¹ across 5 modes and 88 wavelength channels, with high-order formats up to 8-ary pulse-amplitude-modulation (PAM). This study highlights the transformative potential of optical interconnect technologies to surmount the constraints of electronic links, thus setting the stage for next-generation datacenter and optical compute interconnects.

We report fabrication of a multifunctional photonic integrated chip on lithium niobate on insulator, which is achieved by femtosecond laser-assisted chemomechanical polish. We demonstrate a high-extinction-ratio beam splitter, a $1\times 6$ optical switch, and a balanced $3\times 3$ interferometer on the fabricated chip by reconfiguring the microelectrode array integrated with the multifunctional photonic circuit.

We demonstrate efficient tuning of a monolithically integrated lithium niobate (LN) microdisk optical frequency microcomb. Utilizing the high optical quality ($\!Q$) factor (i.e., $Q\sim{7.1} \times {{10}^6}$) of the microdisk, the microcomb spans over a spectral bandwidth of $\sim{200}\,\,{\rm nm}$ at a pump power as low as 20.4 mW. Combining the large electro-optic coefficient of LN and the optimum design of the geometry of microelectrodes, we demonstrate electro-optical tuning of the comb with a spectral range of 400 pm and a tuning efficiency of $\sim{38}\,\,{\rm pm}/{100}\,{\rm V}$.