According to Thide, OAM should allow us to twist together an “infinite number” of conventional transmission protocols without using any more spectrum. In theory, we should be able to take 10 (or 100 or 1000 or…) WiFi or LTE signals and twist them into a single beam, increasing throughput by 10 (or 100 or 1000 or…) times.
The next task for Willner’s team will be to increase the OAM network’s paltry one-meter transmission distance to something a little more usable. “For situations that require high capacity… over relatively short distances of less than 1km, this approach could be appealing. Of course, there are also opportunities for long-distance satellite-to-satellite communications in space, where turbulence is not an issue,” Willner tells the BBC. In reality, the main limiting factor is that we simply don’t have the hardware or software to manipulate OAM. The future of wireless networking is very bright indeed.
Implementation details of the experimental setup. A,C,D,E, multiplexing/demultiplexing of information-carrying OAM beams; B,C,F, data exchange between OAM beams. (D)QPSK, (differential) quadrature phase-shift keying; 16-QAM, quadrature amplitude modulation; PC, polarization controller; EDFA, erbium-doped fibre amplifier; BPF, band-pass filter; DGD, differential group delay; Pol., polarizer; TDL, tunable delay line; AM, amplitude modulator; OC, optical coupler; Col., collimator; HWP, half-wave plate; SLM1-6, spatial light modulator; BS1-3, non-polarizing beamsplitter; BS4, BS5, polarizing beamsplitter; M1-M4, mirror; PM, power metre; EAM, electroabsorption modulator; Att, attenuator; DLI, delay-line interferometre; Rx, receiver; LO, local oscillator; ADC, analog-to-digital converter; DSP, digital signal processing.
Experimental (b) and theoretical results (c1-c5,d1-d3,e1-e4,f1-f3,g1-g3) of the multiplexing/demultiplexing of four OAM beams (OAM-8, OAM+10, OAM+12, OAM-14).