Search

We experimentally measure the contributions of beam distortion and wandering to OAM modal coupling through a random turbulent medium. The inter-modal power coupling further increases under turbulent-medium-induced beam distortions in comparison with the beam-wandering-only cases.

We experimentally demonstrate a 2.25-Gbit/s DPSK free-space optical link that resilience to turbulence-induced modal coupling loss. The measured average mixing loss is ~14.6-dB less than a single-mode-fiber-coupled system based on 200 random turbulence realizations.

We experimentally demonstrate a 6-Gbit/s 16-QAM pilot-assisted self-coherent free-space optical link with enhanced misalignment tolerance. BER performance below the 7% FEC threshold can be achieved for up to 0.13° angular- or 9-mm lateral misalignments.

We experimentally generate a Laguerre-Gaussian (LG ℓ , p ) beam with tunable spatial indices (LG0,0, LG0,1, LG+1,0, and LG+1,1) using integrated circular antenna arrays. A 10-Gbit/s free-space QPSK link carried by the generated LG beam is demonstrated.

We experimentally demonstrate the generation of a space-time pulse in free-space after 1-m multi-mode fiber propagation. The generated space-time pulse has reduced diffraction and a tunable group velocity from 1.0042c to 0.9967c.

We experimentally demonstrate the probing of turbulence along the propagation direction by transmitting multiple complementary pairs of longitudinally structured beams between a single transmitter/receiver aperture pair. The results show probing errors could be reduced by >~25% when using pairs of beams compared to using only one type of beam.

We experimentally demonstrate turbulence-resilient object reconstruction by optoelectronic mixing of sequentially transmitted pairs of Laguerre-Gaussian (LG) modes to measure the object’s LG modal signature. The reconstructed object exhibits resilience to turbulence with D/r0 up to 4.5.

We demonstrate that digital multi-probe time reversal can effectively suppress crosstalk for mode-division multiplexing. The performance of multi-probe time reversal is experimentally characterized over a 340-m free-space link and a 1-km standard multimode fiber.

We experimentally demonstrate wavelength conversion by four-wave mixing in an epsilon-near-zero based metasurface. We observed conversion efficiency of 0.16% using a 127-nm thick metasurface near the 1550-nm C band with 4-GW/cm2 pump peak intensity.

We experimentally demonstrate an 8-Gbit/s QPSK communication link using two multiplexed OAM beams at ~0.3 THz frequency. By tuning the frequency spacing between two lasers, such a system can be operated in the 0.27-0.33 THz range.

We experimentally investigate the degradation of a data-carrying OAM beam passing through dynamic aerosol and non-planar air-water interface and observe an up to -6.5-dB modal crosstalk from OAM -1 to OAM +1 under the effects.

We experimentally demonstrate turbulence mitigation in a 200-Gbit/s OAM-multiplexed free-space optical link with data channels on 1552 nm using simple power measurements on a probe wavelength of 1550 nm without interrupting the data transmission. We observe a crosstalk reduction of up to 25 dB.

We experimentally demonstrate OAM beam generation with tunable order of ℓ ={−1, +1} and 3-dB bandwidth of ~9 nm using a pixel-array structure. A 100-Gbit/s quadrature-phase-shift-keying communication link carried by the tunable OAM beam is demonstrated.

We investigate the thickness-, distance- and loss-dependent interaction between nanoantenna arrays and an epsilon-near-zero (ENZ) thin film. We show the conditions for ultrastrong coupling and the length invariant pinning of antenna resonances on ENZ films.

We experimentally demonstrate adiabatic wavelength conversion using a time-varying epsilon-near-zero-based metasurface. We observe up to 47-mn redshift with 4-GW/cnr pump peak intensity. The wavelength shift depends on both pump-probe delay time and pmnp peak intensity.

We experimentally demonstrate a 400-Gbit/s mode-division-multiplexed free-space-optical communication link using four Laguerre-Gaussian modes or four Hermite-Gaussian modes, achieving a power penalty < 4 dB. The influence of displacement and rotation on system performance is investigated.

We experimentally demonstrate simultaneous pre-and-post adaptive-optics compensation for an OAM-encoded, bi-directional quantum communication link. The atmospheric turbulence-induced quantum-symbol-error-rates are improved by ∼74.0 % and ∼74.1 % in forward and backward channels using the compensation method.

We experimentally demonstrate a free-space, bi-directional quantum communication link encoded by two OAM states using multi-port mode converters. We achieve a quantum-symbol-error-rate of − 0.058 for each channel at 20 Mbit/s/channel when OAM mode-spacing is 4.

We experimentally investigate the performance of a quantum communication link using Laguerre-Gaussian (LG) modes with different radial indices. Quantum symbol error rate (QSER)

We experimentally demonstrate adaptive-optics compensation of emulated atmospheric turbulence for an OAM-based quantum communication link with a classical Gaussian beam used as probe. The turbulence-induced quantum-symbol-error-rate is reduced by « 76 % with the compensation.

We demonstrate the use of orbital angular momentum based spatial spectrum analysis for the estimation of object parameters. The proposed approach is insensitive to object rotation or probing beam diffraction caused by object truncation.

We explore using a switchable detector array to reduce the deadtime effect in an OAM-encoded quantum system. For a 4-OAM-state system, the switchable 16-detector array could provide >15X incident photon rate improvement, as compared to a non-switchable 4-detector array.

We experimentally demonstrate an OAM-based quantum communication link populated by a classical channel. OAM enables an up to 100-Mbit/s quantum data rate as well as an additional 18.5-dB separation between the quantum and classical channels.