Beam steering with ultracompact and low-power silicon resonator phase shifters

Abstract

Photonic integrated circuit (PIC) phased arrays can be an enabling technology for a broad range of applications including free-space laser communications on compact moving platforms. However, scaling PIC phased arrays to a large number of array elements is limited by the large size and high power consumption of individual phase shifters used for beam steering. In this paper, we demonstrate silicon PIC phased array beam steering based on thermally tuned ultracompact microring resonator phase shifters with a radius of a few microns. These resonators integrated with micro-heaters are designed to be strongly coupled to an external waveguide, thereby providing a large and adjustable phase shift with a small residual amplitude modulation while consuming an average power of 0.4 mW. We also introduce characterization techniques for the calibration of resonator phase shifters in the phased array. With such compact phase shifters and our calibration techniques, we demonstrate beam steering with a 1x8 PIC phased array. The small size of these resonator phase shifters will enable lowpower and ultra-large scale PIC phased arrays for long distance laser communication systems.

Photonic Integrated Circuits for an Optical Phased Array

“…Another possible approach to enhance the efficiency of TO phase shifters is to increase the effective light path at the heater region. This can be achieved through the use of a resonance cavity [71] (as illustrated in Figure 10c) or a mode multiplexing system [72] (as shown in Figure 10d). However, it should be noted that this approach is usually wavelength-dependent and could potentially affect the mode intensity during the phase tuning process, as either the resonator or mode coupling is sensitive to the wavelength.…”

Photonic sensor based on mode-split-resonances of weak ring-waveguide coupled microresonator

“…Microresonators (micoring, microsphere, microdisk) have attracted considerable attention for their potential application in wavelength locking [1] , mode selective multiplexer [2] /demultiplexer [3] , phase shifter [4] , photonic differentiator [5] , photonic sensors [6][7] and et.al. Compared with the other optical sensors based on optical fiber grating, optical fiber interferometer or photonic crystal, microresonator-based photonic sensors have the inherit merits of small size, high sensitivity and the possibility of dense integration [8][9] .…”