A Multi-Channel Multi-Bit Programmable Photonic Beamformer Based on Cascaded DWDM

Abstract

We propose and experimentally demonstrate a novel multi-channel multi-bit programmable photonic beamformer, which consists of multiple parallel photonic truetime delay (PTTD) subnetworks based on cascaded DWDMs. Each PTTD subnetwork can provide multi-bit true-time delays (TTDs) for a multi-channel modulated RF signal of a phased array antenna (PAA) and operate over a wide RF range from 10 MHz to 12 GHz. The RF signal is modulated to a spectrally separated laser array combined by a DWDM to form a multi-channel spatially separated PAA. The multi-bit TTDs for scanning PAA angles are rapidly programmed by means of a control circuit of optical switches in the PTTD subnetwork. By using an optical splitter, multiple parallel PTTD subnetworks can be topologically configured out for a PAA with a large number of elements. The obtained radiation patterns demonstrate that the proof-of-concept experimental result agrees well with the theoretical analysis, verifying the feasibility of the proposed photonic beamformer.

Photonic phase control of microwave signal by a combination of two intensity-modulated lightwaves using a Mach-Zehnder optical switch

“…In practical applications for an array antenna, two or more RF channels are needed. Multiple phase-controlled RF signal generation can be achieved by means of a wavelength division multiplexing (WDM) technique [28,29]. The basic configuration is shown in Section 4.…”

Ultrabroadband high-resolution silicon RF-photonic beamformer

“…Microwave photonics technology has enabled the introduction of optical true time delay line (OTTDL) technology into phased array PPAs 8 bringing key advantages in terms of low signal loss and immunity to electromagnetic interference 9 and more importantly, avoiding the appearance of the beam squint effect and extending the operating bandwidths of PAAs 10 . Numerous fiber-based architectures have been proposed for implementing OTTDLs, either based on Bragg gratings 11,12 , highly dispersive fibers 13,14 , or wavelength multiplexing 15,16 . While these approaches have yielded impressive performance, they typically are bulky and require precise cleaving of their length to achieve accurate delays.…”

Performance evaluation of optical beamforming-based wideband antenna array (Invited Paper)

“…Although the near-field or compact-range antenna measurement could be resorted, which requires only a small chamber, some special instruments, such as the planar scanner for near-field probing and the reflector for compact-range implementation, could also bring about an unaffordable cost. This might be a reason for the fact that radiation patterns in most works on optical beamforming were obtained through numerical simulation [23,24] rather than actual field measurement. Actually, the classical antenna theory has provided a pattern multiplication approach to enable field measurement of a large array with a small anechoic chamber [22] .…”