Beam Steerers Information
Beam steerers are used for changing the direction of a laser beam in applications such as topology mapping and barcode scanning. The traditional approach to focusing and deflecting a beam relied on the physical movement of a mirror or lens. Executing the task by mechanical means presented numerous challenges, including high costs, energy consumption, reduced lifespan of the unit, and speed limitations.
The steering principle is based on electronically controlling the optical components that adjust the propagation angle of a laser beam. Optical tools that accommodate a broad range of angles for steering and operate at high speed represent an ideal configuration. Select models offer a compact, inexpensive, and simple construction.
Radio equipment employs beam steering instruments for amplifying the field strength of a radiated signal. A similar concept is implemented in the acoustics field by controlling the intensity and dispersion of the sounds waves. Duran Audio first introduced the use of beam steering integrated with DSP (Digital Signal Processing) via its DDC (Digital Directivity Control) technology. The early 1990s marked an increase in the availability of these products.
Beam steerers serve several communications fields requiring transmission of large amounts of data via optical wireless connections. They exist in applications such as radio astronomy, LiDAR (Light Detection and Ranging), and gas sensing.
How Beam Steerers Work
The beam steering mechanism alters the orientation of the major lobe of an antenna's radiation pattern. The process integrates into radio systems for switching antenna units and modifying the relative phases attributed to the RF signals powering the units.
Video credit: AOptix Technology
Acoustic beam steering functions by aiming the audio output from loudspeakers at the target area. The technique involves modifying the phase and magnitude of multiple speakers. The sound is combined and canceled due to the proximity and vertical alignment of the speakers. The setup, referred to as a line array, facilitates a consistent coverage pattern.
In modern optics, the steering operation is accomplished by adjusting the refractive index of the beam's transmission medium or by relying on lenses, mirrors, prisms, or a rotational diffraction grating. One of the methods features mirror-based gimbals that support rotation of an object. Alternative approaches include galvanometer devices for rotating mirrors, Risley prisms, and systems based on microelectromechanics (MEM) incorporating micro-mirrors.
The beam steering functionality is crucial in applications involving extremely fast switching and scanning. In Gbps connections, networks powered by fiber optics are capable of providing the necessary bandwidth. Optical wireless, on the other hand, relies on beam steerers to generate the needed bandwidth. These systems incorporate optical phased arrays (OPAs) consisting of elements giving off light with controllable phases. The setting creates random phase fronts that drive non-mechanical steering of light. Liquid crystal technology (LCD) is the primary OPA technology that supports large arrays with the ability to control each pixel's phase. LCDs possess a powerful electro-optic response allowing them to produce a large tunable index. In an optical phased array link, silicon photonics guide light on-chip by using high-index contrast waveguides with minimal loss. Silicon materials allow for rapid phase modulation through the thermo-optic effect. Mass fabrication on a CMOS (Complementary Metal-Oxide Semiconductor) platform is possible with integrated steerers.
Standard devices achieve the effect by employing diffractive elements to tune the wavelength. The process covers slow scanning of a beam in a particular direction while steering it rapidly in the opposite direction with an outcoupling grating and Arrayed Waveguide Grating (AWG). The light is carried through the device by the input waveguides. It then breaks down into numerous waveguides, each having individual heaters. The waveguides narrow at a diffractive grating coupler array, where the light is coupled off the chip, undergoing a wavelength shift. Thermo-optic phase tuners allow beam steering at a variety of angles.
Another modern instrument, known as a beamformer, combines beam focusing and defocusing along with the steering and power splitting ability. These products are featured in radar and communications applications that require large-aperture antennas with the capacity to emit beams enabling concurrent transmission, targeting, and tracking. Traditional beamforming networks deploy complex equipment such as power dividers to separate a signal into multiple outputs and maintain an acceptable signal to noise ratio.
Latest models are designed to reduce expense and resource usage. They exploit a transmission-type approach instead of sending the signals from the beamformer's surface components. By contrast to the method based on wave reflection, the phases of incident waves from independent sources are adjusted as they cross the transmission aperture. The alternative transmission architecture utilizes an array that initiates the phase shifts guided by adjustable metal arrangements placed in the pathway. As a result, the waves are combined in the preferred direction and form. In such tools, the array functions as a power splitter, a lens or a beam steerer.
Beam steerers support a myriad of applications, including:
- Bar-code scanning
- LiDAR (Light Detection and Ranging)
- Gas detection
- Topology mapping
- Laser rangefinding
- Radio Astronomy
Beam steerers offer a diverse set of features for specialized applications. When choosing a device, check the manufacturer's specifications to ensure the operational parameters of the instrument meet your requirements. Consider evaluating the new approaches to beamforming involving transmission compared to reflection oriented architecture to identify equipment best suited for the intended use.
GOST 23066 - Beam steering arrangements for phased array antennas