Precise electron beam-based target-wavelength trimming for frequency conversion in integrated photonic resonators

Abstract

We demonstrate post-fabrication target-wavelength trimming with a gallium phosphide on a silicon nitride integrated photonic platform using controlled electron-beam exposure of hydrogen silsesquioxane cladding. A linear relationship between the electron-beam exposure dose and resonant wavelength red-shift enables deterministic, individual trimming of multiple devices on the same chip to within 30 pm of a single target wavelength. Second harmonic generation from telecom to near infrared at a target wavelength is shown in multiple devices with quality factors on the order of 104. Post-fabrication tuning is an essential tool for targeted wavelength applications including quantum frequency conversion.

Photocatalytic Oxidation in Few‐Layer Tellurene for Loss‐Invariant Integrated Photonic Resonance Trimming

“…The sustaining power-free and shape-preserved resonance correction are critical for sys-tem applications involving multi-wavelength operations, such as low-power optical interconnects in wavelength division multiplexing systems and spin qubits quantum computing in silicon photonics. [24][25][26][27][28]…”

“…Resonance trimming is needed for on-chip wavelength correction. As demanded by the system applications, [24][25][26] direct laser oxidation of the silicon layer has been the primary way of resonance trimming. [27,28] The activation energy of silicon photo-oxidation requires visible photons with three orders of magnitude higher fluence (532 nm, ≈4J fluence) for reaching a similar wavelength trimming range (≈0.2 nm) in photonic crystal cavities.…”

Triply-Resonant Sum Frequency Conversion with Gallium Phosphide Ring Resonators

“…Perhaps the most critical challenge, however, will be achieving triple resonance from a precise defect optical transition frequency to a target telecom frequency. This will require further advancement in multiple independent, or quasi-independent resonator tuning mechanisms [31,34]. Once achieved, the impact of triply-resonant devices would extend to wavelength multiplexing for quantum networks and the elimination of emitter wavelength inhomogeneity.…”

“…Each term in the overlap is a product of one vertical and two in-plane field components, which in practice restricts mode selection to one TM and two TE modes. The difference in interactions between radial and azimuthal field components in the 𝑀 = +2 and 𝑀 = −2 cases biases the overlap integral toward the inside and outside edge of the ring, respectively, which allows significant interactions between modes with even and odd symmetry [31].…”

“…Fitted curves for the CW and pulsed power dependence measurements yielded small-signal conversion efficiencies 9.5%/mW and 8%/mW, respectively. The variation in measured conversion efficiency may be due to slight variations in input laser alignment or gradual changes in the HSQ cladding [31] altering the optimal temperature of the device.…”