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Ultraviolet and visible integrated photonics enable applications in quantum information, sensing, and spectroscopy, among others. Few materials support low-loss photonics into the UV, and the relatively low refractive index of known depositable materials limits the achievable functionality. Here, we present a high-index integrated photonics platform based on HfO2and Al2O3composites deposited via atomic layer deposition (ALD) with low loss in the visible and near UV. We show that Al2O3incorporation dramatically decreases bulk loss compared to pure HfO2, consistent with inhibited crystallization due to the admixture of Al2O3. Composites exhibit refractive indexnfollowing the average of that of HfO2and Al2O3, weighted by the HfO2fractional compositionx. Atλ = 375 nm, composites withx = 0.67 exhibitn = 2.01, preserving most of HfO2’s significantly higher index, and 3.8(7) dB/cm material loss. We further present fully etched and cladded waveguides, grating couplers, and ring resonators, realizing a single-mode waveguide loss of 0.25(2) dB/cm inferred from resonators of 2.6 million intrinsic quality factor atλ = 729 nm, 2.6(2) dB/cm atλ = 405 nm, and 7.7(6) dB/cm atλ = 375 nm. We measure the composite’s thermo-optic coefficient (TOC) to be 2.44(3) × 10−5RIU/°C nearλ = 397 nm. This work establishes (HfO2)x(Al2O3)1−xcomposites as a platform amenable to integration for low-loss, high-index photonics spanning the UV to NIR.
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Two-dimensional extreme skin depth engineering for CMOS photonics
Extreme skin depth engineering (e-skid) can be applied to integrated photonics to manipulate the evanescent field of a waveguide. Here we demonstrate thate-skidcan be implemented in two directions in order to deterministically engineer the evanescent wave allowing for dense integration with enhanced functionalities. In particular, by increasing the skin depth, we enable the creation of two-dimensional (2D)e-skiddirectional couplers with large gaps and operational bandwidth. Here we experimentally validate 2De-skidfor integrated photonics in a complementary metal–oxide semiconductor (CMOS) photonics foundry and demonstrate strong coupling with a gap of 1.44 µm.
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- Award ID(s):
- 1810282
- PAR ID:
- 10218635
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Journal of the Optical Society of America B
- Volume:
- 38
- Issue:
- 4
- ISSN:
- 0740-3224; JOBPDE
- Format(s):
- Medium: X Size: Article No. 1307
- Size(s):
- Article No. 1307
- Sponsoring Org:
- National Science Foundation
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