A research team from the King Abdullah University of Science and Technology (KAUST) has developed optical fibres with perovskite nanocrystals, which has revealed groundbreaking prospects for photodetectors for high-speed, free-space, and underwater data links.
How can perovskite nanocrystals improve current underwater wireless communication systems?
In current free-space and underwater optical wireless communication systems, there is often an adjustment between the size of a photodetector and its bandwidth; the more extensive area devices capture more light. However, this is at the expense of a slower maximum data speed.
Chun Hong Kang, Boon Ooi, and their research team have designed and fabricated luminescent polymer optical fibres fixed with perovskite nanocrystals of CsPbBr3, which act as a large-area scintillator.
Researchers hypothesised that the fibres would absorb the optical data signal transmitted in the violet spectral region (around 400 nanometres) and then reemit it in the green region (approximately 510 nm) so that a fast avalanche photodetector can detect it.
What was the result of this experiment?
This experiment resulted in an omnidirectional detector system that can be scaled to large areas and operate at a data transmission of hundreds of megabits per second, making it significantly beneficial for fast underwater optical communications.
“We hope to pave the way towards the full-scale commercialisation of optical-based wireless network systems that offer high bandwidth capacity, lower latency, and faster data rates than existing micro and millimetre wave technology,” explained post-doctorate, Chun Hong Kang.
“This includes bringing the optical wireless internet system to the underwater environment, where the existing technology based on acoustic and radio-frequency (RF) waves suffer significantly in terms of the data rate due to the high attenuation in water.”
Experimental tests conducted so far at a wavelength of 405 nm depict that the scientists’ detector system offers a 3dB bandwidth of 13.1 MHz, allowing data transmission speeds of up to 152.5 Mbit/s.
How do scientists intend to improve this technology further?
Ooi is confident that the performance can be developed even further by optimising the properties of the perovskite nanocrystals utilised. Researchers are currently working closely with material scientists at KAUST, notably the groups of Osman Bakr and Omar Mohammed, with this intention in mind.
“The primary limiting factor for the modulation bandwidth of fibre-based detectors is the recombination lifetime of the perovskite-based luminescent material embedded within the polymer fibres,” Ooi concluded.
“We anticipate that perovskite-based luminescent material —with a faster recombination lifetime in the range of picoseconds allowing a gigahertz bandwidth — can be realised in the future through several synthesis and optimisation strategies.”
Thus, using several perovskite nanocrystals of different compositions, with each emitting light at a different wavelength, could also enable simultaneous transmission and detection of multiple wavelength channels to boost data capacity further.