Research Terms
UCF researchers have developed a new fabrication process for making stretchable electronic and optoelectronic devices, circuits or systems that can conform or deform to specific shapes. The new process enables manufacturers to make circuits for advanced imaging systems, wearable electronics, and flexible devices for the internet-of-things.
Current processes for producing curved, stretchable or flexible electronic devices provide limited functionality. For example, the devices are rigid or only accommodate very shallow curvatures. Also, they may bend, but only in one direction at a time. The current approaches also result in low density in the active circuit and low levels of interconnectivity. By comparison, the new invention enables manufacturers to arrange circuits that conform to arbitrarily shaped surfaces and stretch to complex shapes, such as the shape of a hemisphere for image sensors. The new process solves the classic imaging problems related to flat lens designs, which require large, complex, costly optics to correct the flat detector plane. In addition, manufacturers can produce image sensors with high pixel density and the interconnectivity needed to control and read such sensors.
Technical Details
A manufacturer can use the process to create flexible circuits or devices in a variety of ways. For example, one method starts with a custom silicon wafer-based circuit of one or more devices or elements that are electrically isolated from each other. The next step is to affix or monolithically integrate a stretchable polymer backplane to the circuit. To make the circuit flexible, the method uses techniques such as dicing or etching to partition the wafer into multiple segments or "islands." By electrically interconnecting the segments through the stretchable backplane, the method produces a high-density and highly interconnected circuit. Multilayered interconnects embedded in, on or beneath the backplane can also provide an interface to external electronics that are not part of the circuit. The resulting, interconnected and flexible circuit may be encapsulated and/or packaged. The new fabrication technology can use a variety of electronic materials, including (but not limited to) silicon, GaAs, InSb, PbSe, CdTe, organic semiconductors, metal oxide semiconductors and related alloys or hybrid combinations of materials.
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.
Researchers at the University of Central Florida have invented a photonic integrated circuit (PIC) array device that can provide the emitter and detector array capabilities that imaging-based beam steering (IBBS) systems need to achieve high-resolution, dynamic beam steering over a wide field-of-view (FOV). The UCF invention, which includes an IBBS system design, offers a passive, low-cost, compact system with power-efficient data links for applications such as free-space optical communications (FSOC), optical range imaging (LIDAR), and other structured illumination technologies. The invention is also naturally multiplexed to provide parallel communications between potentially large numbers of remote devices.
IBBS provides simultaneous control of multiple lines of sight, enabling independent and simultaneous (multiplexed) addressing into the field of regard (FOR). As a result, IBBS can be used for multiplexed communication to numerous devices from a single aperture in an FSOC system. IBBS multiplexed addressing may also enable multiplexed ranging for LIDAR imaging to improve frame rates while maintaining eye-safe emissions from the aperture. However, IBBS configurations today are unable to use the full potential of IBBS, as they lack the high-density emitter arrays capable of independent high-bandwidth emission from individual pixels as well as high-speed electronic control.
The UCF invention offers a low-cost solution that provides scalable, high-density emitter and detector array circuits using mature fabrication processes that are ideally suited for compact IBBS systems.
Technical Details
Comprising a novel PIC coupler array device and an IBBS system design, the UCF invention uses photonic integrated circuit technologies to dynamically route high-bandwidth optical signals to a target pixel in a 2D array of grating outcouplers. The invention includes uni-directional (transmit only) or bi-directional (combined transmit and receive functionality) optoelectronic circuits integrated on-chip to provide versatile beam-steering capabilities when combined with an imaging optic in an IBBS system. The circuits support multiple optical signals using low-loss and scalable routing techniques to enable scaling into large arrays for precision pointing over a large FOR.
In one example configuration, the UCF IBBS system includes multiple input light sources and a PIC coupler array that can selectively route optical signals into and out of a coupler plane. Thus, the PIC coupler array may operate as a high-density input coupler, output coupler, or multi-directional coupler. The PIC coupler array can also include multiple feed networks with cascading switch networks to selectively route the input signals from a particular feed-line waveguide to a selected pixel-network waveguide. As a result, light may be coupled into or out of the couplers through multiple paths.
Partnering Opportunity
The research team is looking for partners to develop the technology further for commercialization.
Imaging-based beam steering for free-space optical communication, Applied Optics, Vol. 58, Issue 13, pp. D12-D21 (2019), S.S. Polkoo and C.K. Renshaw. https://doi.org/10.1364/AO.58.000D12.