Electrically induced adiabatic frequency conversion in an integrated lithium niobate ring resonator.

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.

Optical path length and trajectory stability in rotationally asymmetric multipass cells.

We describe the behavior of optical trajectories in multipass rotationally asymmetric cavities (RACs) using a phase-space motivated approach. Emphasis is placed on generating long optical paths. A trajectory with an optical path length of 18 m is generated within a 68 cm3 volume. This path length to volume ratio (26.6 cm-2) is large compared to current state of the art multipass cells such as the cylindrical multipass cell (6.6 cm-2) and astigmatic Herriott cell (9 cm-2). Additionally, the effect of small changes to the input conditions on the path length is studied and compared to the astigmatic Herriott cell. This work simplifies the process of designing RACs with long optical path lengths and could lead to broader implementation of these multipass cells.