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Integrated optical phased arrays (OPAs) have enabled cutting-edge applications where optical beam steering can benefit from chip-scale integration. However, the majority of integrated OPA demonstrations to date have been limited to showing far-field beam forming and steering. There are, however, many emerging applications of integrated photonics where emission of focused light from a chip is desirable, such as in integrated optical tweezers for biophotonics, chip-based 3D printers, and trapped-ion quantum systems. To address this need, we have recently demonstrated the first near-field-focusing integrated OPAs; however, this preliminary demonstration was limited to emission at only one focal plane above the chip. In this paper, we show the first, to the best of our knowledge, spiral integrated OPAs, enabling emission of focusing beams with tunable variable focal heights for the first time. In the process, we develop the theory, explore the design parameters, and propose feed-structure architectures for such OPAs. Finally, we experimentally demonstrate an example spiral integrated OPA system fabricated in a standard silicon-photonics process, showing wavelength-tunable variable-focal-height focusing emission. This work introduces a first-of-its-kind integrated OPA architecture not previously explored or demonstrated in literature and, as such, enables new functionality for emerging applications of OPAs that require focusing operation.
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A 160 GHz Frequency Quadrupler based on Heterogeneous Integration of GaAs Schottky Diodes onto Silicon using SU-8 for Epitaxy Transfer
An integrated frequency quadrupler operating at 160 GHz, producing 100 mW of output power, and achieving peak efficiency of 25.5% is described. The quadrupler design is based on prior art and consists of GaAs Schottky diodes with epitaxy transferred to a micromachined silicon carrier forming a heterogeneously-integrated chip. A newly-developed fabrication process that eliminates high temperature annealing and utilizes SU-8 for adhesive bonding was employed to realize the circuit. The new process improves device yield and reliability compared to previous implementations.
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- Award ID(s):
- 1731635
- PAR ID:
- 10065057
- Date Published:
- Journal Name:
- 2018 IEEE MTT-S International Microwave Symposium (IMS)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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