TY - JOUR
T1 - Experimental Demonstration of Sub-THz Wireless Communications Using Multiplexing of Laguerre-Gaussian Beams When Varying two Different Modal Indices
AU - Minoofar, Amir
AU - Su, Xinzhou
AU - Zhou, Huibin
AU - Zhang, Runzhou
AU - Alishahi, Fatemeh
AU - Zou, Kaiheng
AU - Song, Hao
AU - Pang, Kai
AU - Zach, Shlomo
AU - Tur, Moshe
AU - Molisch, Andreas F.
AU - Sasaki, Hirofumi
AU - Lee, Doohwan
AU - Willner, Alan E.
N1 - Publisher Copyright:
© 1983-2012 IEEE.
PY - 2022/5/15
Y1 - 2022/5/15
N2 - The ability to multiplex multiple structured beams for sub-terahertz (sub-THz) wireless communications has been recently explored. The spatial orthogonality of structured beams enables mode-division multiplexing (MDM). In an MDM system, multiple data-carrying beams are transmitted and received simultaneously through a single aperture pair with low inherent crosstalk. This can increase data capacity and spectral efficiency of the system. Here, we experimentally demonstrate multiplexing orthogonal sub-THz Laguerre-Gaussian (LGℓ,p) beams when varying two different modal indices (i.e., both ℓ and p); this contrasts with prior reports when varying only one index (i.e.,ℓ) and could potentially provide a larger set of channels and beams in an MDM system. In our demonstration, specially designed phase patterns are used: (1) at the transmitter, to convert two THz Gaussian beams to two different LG beams, each carrying an independent data channel; and (2) at the receiver, to separate and convert the LG beams back to Gaussian-like THz beams. An 8-Gbit/s quadrature-phase-shift-keying (QPSK) link containing two multiplexed LG modes over 40 cm is experimentally demonstrated. For the above link, three different LG modal sets are chosen (i.e., LG- 2,0 and LG1,1 or LG3,0 and LG0,1 or LG2,1 and LG0,1). All channels are recovered with bit errorrates (BERs) below the 7% forward error correction (FEC) limit. The experimental results indicate that: (a) higher-order LG modes experience more divergence, larger size, and lower conversion efficiency, contributing to higher power loss; and (b) the modal coupling and crosstalk for different LG modes is <-12 dB, which could be due to the transmitter/receiver misalignments as well as beam truncation by the limited-sized receiver aperture.
AB - The ability to multiplex multiple structured beams for sub-terahertz (sub-THz) wireless communications has been recently explored. The spatial orthogonality of structured beams enables mode-division multiplexing (MDM). In an MDM system, multiple data-carrying beams are transmitted and received simultaneously through a single aperture pair with low inherent crosstalk. This can increase data capacity and spectral efficiency of the system. Here, we experimentally demonstrate multiplexing orthogonal sub-THz Laguerre-Gaussian (LGℓ,p) beams when varying two different modal indices (i.e., both ℓ and p); this contrasts with prior reports when varying only one index (i.e.,ℓ) and could potentially provide a larger set of channels and beams in an MDM system. In our demonstration, specially designed phase patterns are used: (1) at the transmitter, to convert two THz Gaussian beams to two different LG beams, each carrying an independent data channel; and (2) at the receiver, to separate and convert the LG beams back to Gaussian-like THz beams. An 8-Gbit/s quadrature-phase-shift-keying (QPSK) link containing two multiplexed LG modes over 40 cm is experimentally demonstrated. For the above link, three different LG modal sets are chosen (i.e., LG- 2,0 and LG1,1 or LG3,0 and LG0,1 or LG2,1 and LG0,1). All channels are recovered with bit errorrates (BERs) below the 7% forward error correction (FEC) limit. The experimental results indicate that: (a) higher-order LG modes experience more divergence, larger size, and lower conversion efficiency, contributing to higher power loss; and (b) the modal coupling and crosstalk for different LG modes is <-12 dB, which could be due to the transmitter/receiver misalignments as well as beam truncation by the limited-sized receiver aperture.
KW - Laguerre-Gaussian modes
KW - mode-division multiplexing (MDM)
KW - terahertz communication
KW - terahertz photonics
UR - http://www.scopus.com/inward/record.url?scp=85124716663&partnerID=8YFLogxK
U2 - 10.1109/JLT.2022.3149976
DO - 10.1109/JLT.2022.3149976
M3 - מאמר
AN - SCOPUS:85124716663
VL - 40
SP - 3285
EP - 3292
JO - Journal of Lightwave Technology
JF - Journal of Lightwave Technology
SN - 0733-8724
IS - 10
ER -