Imaging-Based Transmitter and Receiver for Free-Space Optical Communications

Abstract

Researchers at the University of Central Florida have developed a robust and cost-effective solution for line-of-site control (LOS) also known as beam steering in emerging free-space optical communications (FOC) systems. Instead of using conventional radio frequencies, FOC systems employ optical domain carrier frequencies to establish direct LOS data links between transmitters and receivers. The systems are immune to jamming and eavesdropping, thus enabling secure high-bandwidth communications. However, despite these capabilities, current FOC systems are bulky and expensive, impeding their use in intermediate distance communications, especially when the host platform or the transceiver is mobile.

UCF's imaging-based beam steering (IBBS) technology offers a solution by enabling precision beam steering over a wide FOV using low-cost components with no moving parts. Naturally multiplexed to provide parallel communications between large numbers of remote devices, the invention also uses less power. Thus, the new system is well suited for use in intermediate distance communications, such as a hub for mobile end-user-devices. The IBBS system can also be part of a mesh network to increase the communication range of radio-frequency-congested environments.

Technical Details

The UCF invention consists of an imaging receiver (Rx) and transmitter (Tx) that enable high-resolution mapping between object and image space to provide LOS control for compact, low-cost FOC systems. The Rx and Tx consist of pixelated photodetector and emitter arrays positioned at or near the focal surface of a wide FOV lens assembly. The optical system of the Rx closely resembles that of a camera that similarly maps the light field in front of the system onto a sensor surface to produce an image of object space. In contrast, the Tx resembles an ?inverse-camera? wherein an emitter array is used in place of the sensor so that the lens projects each pixel into a unique direction in object space. The design allows multiplexed communications with hundreds of remote devices simultaneously.

The IBBS array can provide multiple, independently modulated beams simultaneously and does not require phase control at each pixel, nor loses power into sidelobes. It also does not require wide-angle emission from the array itself. In experimental setups, the technology showed efficient collection and collimation of light from an organic LED array into 1.24 milliradians (mrad) divergence beams with pointing accuracy of 5.5 mrad and demonstrated a 41 m optical link. Simulations and scaling analysis of IBBS-FOC links predict effective ranges of more than 1 km using high-brightness vertical-cavity surface-emitting laser arrays.

Partnering Opportunity

The research team is looking for partners to develop the technology further for commercialization.

Benefit

Market Application