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With the ever-increasing need for higher data rates, datacom and telecom industries are now migrating to silicon photonics to achieve higher data rates with reduced manufacturing costs. However, the optical packaging of integrated photonic devices with multiple I/O ports remains a slow and expensive process. We introduce an optical packaging technique to attach fiber arrays to a photonic chip in a single shot using CO₂laser fusion splicing. We show a minimum coupling loss of 1.1 dB, 1.5 dB, and 1.4 dB per-facet for 2, 4, and 8-fiber arrays (respectively) fused to the oxide mode converters using a single shot from the CO₂laser.

The lack of a bulk second-order nonlinearity (χ⁽²⁾) in silicon nitride (Si₃N₄) keeps this low-loss, CMOS-compatible platform from key active functions such as Pockels electro-optic (EO) modulation and efficient second harmonic generation (SHG). We demonstrate a successful induction ofχ⁽²⁾in Si₃N₄through electrical poling with an externally-applied field to align the Si-N bonds. This alignment breaks the centrosymmetry of Si₃N₄, and enables the bulkχ⁽²⁾. The sample is heated to over 500°C to facilitate the poling. The comparison between the EO responses of poled and non-poled Si₃N₄, measured using a Si₃N₄micro-ring modulator, shows at least a 25X enhancement in ther₃₃EO component. The maximumχ⁽²⁾we obtain through poling is 0.30pm/V. We observe a remarkable improvement in the speed of the measured EO responses from 3 GHz to 15 GHz (3 dB bandwidth) after the poling, which confirms theχ⁽²⁾nature of the EO response induced by poling. This work paves the way for high-speed active functions on the Si₃N₄platform.

Changing the frequency of light outside the laser cavity is essential for an integrated photonics platform, especially when the optical frequency of the on-chip light source is fixed or challenging to be tuned precisely. Previous on-chip frequency conversion demonstrations of multiple GHz have limitations of tuning the shifted frequency continuously. To achieve continuous on-chip optical frequency conversion, we electrically tune a lithium niobate ring resonator to induce adiabatic frequency conversion. In this work, frequency shifts of up to 14.3 GHz are achieved by adjusting the voltage of an RF control. With this technique, we can dynamically control light in a cavity within its photon lifetime by tuning the refractive index of the ring resonator electrically.