With the rapid develop of information era, there is an increasing demand on the transmission capacity ofcommunicationsystems. The existing fiber optical communication systems face great challenge. Lots of new techniques are emerging to overcome the capacity crunch of optical communications, among which fiber-based orbital angular momentum (OAM) communications may provide a possible solution.
Jian Wang’s groupat Wuhan National Laboratory for Optoelectronics (WNLO), Multi-Dimensional Photonics Laboratory (MDPL), has been devoted to the research of fiber OAM communications for many years and achieved a series of progress:
Firstly,in long-distance OAM fiber transmission, Jian Wang’s group analyzed the OAM mode transmission performance. By using LDPCcodes to mitigate the influence of mode crosstalk and DMD for long-distance fiber OAM modes transmission,PhD candidate Andong Wang from MDPL demonstrated OAM modes transmission and multiplexing in 50-km fiber (Optics Express Vol. 24, PP.11716-11726, 2016).
Figure 1 Concept and principle of strong mode coupling in long-distance OAM transmission.
Moreover, Jian Wang’s group also achieved a series of progress in fiber OAM communication. Directed by Prof.JianWang, PhD candidatesChen Si and Jun Liu cooperating with Dr. Cheng Du and Mr. Qi Mo in Fiberhome Telecommunication Technologies Co. Ltd, demonstratedfull-duplex bidirectional data transmission link using twisted lights multiplexing over 1.1-km orbital angular momentum fiber (Optics Express 2416934-16944, 2016). In addition, by using the supported modes in optical fiber, PhD candidatesLong Zhu et al., realized image transfer by employing mode encoding/decoding in km-scale fiber (Optics Letters 41, 1969, 2016). Furthermore, PhD candidate Jun Liu from MDPL, directed By Prof. Wang, cooperated with Sun Yatsen University, University of Glasgow and Fiberhome Telecommunication Technologies, has demonstrated and evaluated the performance of analog signal transmission system with photonic integrated optical vortex emitter and 3.6-km few-mode fiber (FMF) link using OAM modes (Optics Letters 41, 1969-1972, 2016).
Figure 2 Concept of full-duplex bidirectional data transmission using twisted lights multiplexing over 1.1-km OAM fiber.
Figure 3 Concept of image transfer using mode encoding/decoding in km-scale fiber.
Figure 4 Experimental setup of an analog signal transmission system with photonic integrated optical vortex emitter and 3.6-km FMF link.
In addition, Prof. JianWang’s group designedtwo kindsof fiber converter to realize low-cost, versatile all-fiber OAM conversion. PhD candidate Liang Fang proposedfiber helical gratings (HGs) for flexible generation, conversion, and exchange of fiberguided OAM modes (IEEE Journal of Quantum Electronics 52, 6600306, 2016). It is expected that the proposed scheme is a promising method for fiber-based generation,date exchange, and spectra processing of OAM modes, and mayhave some potential applications in OAM multiplexing in fibercommunications. Moreover, directedby Prof.JianWang, cooperating with Dr. Cheng Du and Mr. Qi Mo in Fiberhome Telecommunication Technologies Co. Ltd, PhD candidate Jun Liu, demonstratedall fiber pre- and post-data exchange in km-scale fiber-based twisted lights multiplexing(Optics Letters 41,3896-3899, 2016).
Figure 5 (a) Scheme of helical gratings (HGs) OAMconverter.(b) Concept of all-fiber pre- and post-data exchange functions in an OAM-SDM network.
These works arepartiallysupported by the National Basic Research Program of China (973Program) (2014CB340004),the NationalNatural Science Foundation of China (NSFC) (11274131,11574001,61222502),the Program for New Century ExcellentTalents in University (NCET-11-0182),and theWuhan Science andTechnology Plan Project (2014070404010201).
Links of the published papers:
[1] Andong Wang, Long Zhu, Shi Chen, Cheng Du, Qi Mo, and Jian Wang*, “Characterization of LDPC-coded orbital angular momentum modes transmission and multiplexing over a 50-km fiber,”OpticsExpress 24(11), 11716-11726 (2016).
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-11-11716
[2] Shi Chen, Jun Liu, Yifan Zhao, Long Zhu, Andong Wang, Shuhui Li, Jing Du, Cheng Du, Qi MoandJian Wang*, “Full-duplex bidirectional data transmission link using twisted lights multiplexing over 1.1-km orbital angular momentum fiber,” Scientific Reports 6, 38181 (2016).
http://www.nature.com/articles/srep38181
[3] Long Zhu, JunLiu, Qi Mo, Cheng Du, and Jian Wang, “Encoding/decoding using superpositions of spatial modes for image transfer in km-scale few-mode fiber,” Opt. Express 24(15), 16934-16944 (2016).
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-15-16934
[4] Jun Liu, Shimao Li, Jing Du, Charalambos Klitis, Cheng Du, Qi Mo, Marc Sorel, Siyuan Yu, Xinlun Cai, and Jian Wang*, “Performance evaluation of analog signal transmission in an integrated optical vortex emitter to 3.6-km few-mode fiber system,” Optics Letters 41(9), 1969-1972 (2016).
https://www.osapublishing.org/ol/abstract.cfm?uri=ol-41-9-1969
[5] Liang Fang and Jian Wang*, “Mode conversion and orbital angular momentum transfer among multiple modes by helical gratings,” IEEE Journal of Quantum Electronics, 52(8),66003062016.
http://ieeexplore.ieee.org/abstract/document/7491350/
[6] Jun Liu, Long Zhu, Andong Wang, Shuhui Li, Shi Chen, Cheng Du, Qi Mo, and Jian Wang*, “All fiber pre- and post-data exchange in km-scale fiber-based twisted lights multiplexing,” Opt. Lett. 41(16), 3896 (2016).
https://www.osapublishing.org/ol/abstract.cfm?uri=ol-41-16-3896
