Demonstration of a photonically controlled RF phase shifter

Abstract

Integrated photonic radio frequency (RF) phase shifters with dc voltage control have been realized using a nested dual Mach-Zehnder modulator configuration in a new nonlinear optical polymer, CLD2-ISX. These modulators have a V V V of 10.8 V and exhibit excellent frequency performance measured up to 20 GHz. A near linear phase shift exceeding 108was obtained for a 16-GHz microwave signal by tuning the dc control voltage over a 7.8-V range. It is expected that these integrated polymer phase shifters will find widespread applications in new types of lightweight optically controlled phased array systems.

Theory study on a photonic-assisted radio frequency phase shifter with direct current voltage control

“…With direct current (DC) voltage control, photonic phase shifters can be used to control multiple RF phases and feed the frequencyindependent phase outputs into an phased array antenna to perform rapid and continuous beam-forming functions. [5,6] For all phase shifters, the following four characteristics should be met: [7,8] 1) a phase accuracy of 3 • to satisfy most applications; 2) a phase control range of modulo-2π; 3) the ability to set the phase of an RF signal without altering its magnitude; and 4) low cost to enable individual element phase control. Various approaches to obtain photonic phase shifters have been reported.…”

“…[18] In Ref. [5], a polymer-based RF phase shifter was proposed, which is composed of three phase modulation arms. The upper two arms are modulated with RF signal, and the third arm is driven by DC voltage.…”

“…For example, in Ref. [5] a desired performance can only be realized by setting the modulation index to 2.71, and in Ref. [6] the modulation should be carefully set according to the optical power-splitting ratio at the balancing arm.…”

“…In this work, using the same technology as in Refs. [5] and [6] we propose an RF phase shifter with direct current voltage control as in Refs. [5] and [6].…”

All-fiber electro-optic modulator based on D-shaped twin-core fiber

“…Furthermore, EO polymer-based optical modulators offer several advantages over the mature LiNbO 3 modulators due to the exclusive properties of polymer materials [2] . For the advantages of polymer materials, EO polymer modulators have shown great potential for a variety of applications, such as analog-to-digital conversion [3] , a phased-array radar [4] , electromagnetic field sensing [5] , etc. However, a high propagation loss of about 2 dB/cm is observed in EO polymer waveguides, which hinders its further development and application [6] .…”