# Gallium Arsenide Optical Phased Array Photonic Integrated Circuit

**Authors:** Michael Nickerson, Bowen Song, Jim Brookhyser, Gregory Erwin, Jan Kleinert, Jonathan Klamkin  
**arXiv:** [2304.03417](https://arxiv.org/abs/2304.03417)  
**Date:** 2023-04-06  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.03417v1/

## Key points

- A 16-channel optical phased array developed on a GaAs photonic integrated circuit (PIC) platform
- Tested with a 1064 nm external laser
- Demonstrated a beamwidth of 0.92 degrees
- Grating-lobe-free steering range of 15.3 degrees
- Sidelobe level of 12 dB
- Phase modulators based on reverse biased p-i-n structure, 3 mm long with DC power consumption <5 μW and electro-optical bandwidth >770 MHz
- Individual phase modulators tested at various wavelengths (980 nm to 1360 nm)
- Modulation efficiency ranging from 0.5 V·cm to 1.23 V·cm
- Low complexity fabrication process involving seven mask sets, two GaAs etches, and two metal lift-off steps
- Promising development in the field of optical phased arrays for practical applications in free-space optical communication systems and LiDAR systems

## Summary

A 16-channel optical phased array has been developed on a gallium arsenide (GaAs) photonic integrated circuit (PIC) platform using a low-complexity fabrication process. The array was tested with a 1064 nm external laser and demonstrated a beamwidth of 0.92 degrees, a grating-lobe-free steering range of 15.3 degrees, and a sidelobe level of 12 dB. The component phase modulators, based on a reverse biased p-i-n structure, were found to be 3 mm long with DC power consumption of less than 5 μW and an electro-optical bandwidth greater than 770 MHz. In addition, individual phase modulators based on the same structure were tested at various wavelengths ranging from 980 nm to 1360 nm. These modulators showed single-sided Vπ·L modulation efficiency ranging from 0.5 V·cm to 1.23 V·cm. The fabrication process for the PIC was designed to have low complexity and involved seven mask sets, two GaAs etches, and two metal lift-off steps. Schematic diagrams of the primary fabrication process steps are provided in Figure 5 for reference. This research presents a promising development in the field of optical phased arrays by demonstrating successful fabrication of a GaAs-based PIC with high performance characteristics such as wide steering range and low sidelobe levels. Moreover, the use of low complexity processes makes this technology more accessible for practical applications in areas such as free-space optical communication systems and LiDAR systems.