ABSTRACT
Optical wireless communication (OWC) links suffer from strict requirements of pointing, acquisition, and tracking (PAT) between the transmitter and receiver. Extending the narrow field-of-view (FoV) of conventional light-focusing elements at the receiver side can relax the PAT requirements. Herein, we use all-inorganic CsPbBr3 nanocrystals (NCs) to extend various optical concentrators' FOV to 60°, regardless of the original FOV values of the concentrators. Given the robustness of UV light against communication channel misalignment, the used CsPbBr3 NCs provide another advantage of converting transmitted UVC light into a green color that matches the peak absorption of the widely available Si-based detectors. We evaluated the feasibility of the reported wide FoV optical detectors by including them in deep UV OWC systems, deploying non-return-to-zero on-off keying (NRZ-OOK) and orthogonal-frequency division multiplexing (OFDM) modulation schemes. The NRZ-OOK and OFDM schemes exhibit stable communication over the 60° FoV, providing data transmission rates of 100 Mb/s and 71.6 Mb/s, respectively, a unique capability to the reported design.
ABSTRACT
The use of optical carrier frequencies will enable seamless data connection for future terrestrial and underwater internet uses and will resolve the technological gap faced by other communication modalities. However, several issues must be solved to propel this technological shift, which include the limitations in designing optical receivers with large detection areas, omnidirectionality, and high modulation bandwidth, mimicking antennas operating in the radio-frequency spectrum. To address this technological gap, herein, we demonstrate halide-perovskite-polymer-based scintillating fibers as a near-omnidirectional detection platform for several tens-to-hundreds of Mbit/s optical communication in both free space and underwater links. The incorporation of all-inorganic CsPbBr3 nanocrystals by engineering the nanocrystal concentration in an ultraviolet-curable polymer matrix ensures a high photoluminescence quantum yield, Mega-Hertz modulation bandwidth and Mbit/s data rate suitable to be used as a high-speed fibers-based receiver. The resultant perovskite polymer-based scintillating fibers offer flexibility in terms of shape and near-omnidirectional detection features. Such fiber properties also introduce a scalable detection area which can resolve the resistance-capacitance and angle-of-acceptance limits in planar-based detectors, which conventionally impose a trade-off between the modulation bandwidth, detection area, and angle of view. A high bit rate of 23 Mbit/s and 152.5 Mbit/s was achieved using an intensity-modulated laser for non-return-to-zero on-off-keying (NRZ-OOK) modulation scheme in free-space and quadrature amplitude modulation orthogonal frequency-division multiplexing (QAM-OFDM) modulation scheme in an underwater environment, respectively. Our near-omnidirectional optical-based antenna based on perovskite-polymer-based scintillating fibers sheds light on the immense possibilities of incorporating functional nanomaterials for empowering light-based terrestrial- and underwater-internet systems.
