{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:55:51Z","timestamp":1760237751964,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,6,24]],"date-time":"2020-06-24T00:00:00Z","timestamp":1592956800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST 108-2221-E-150-041 and MOST 108-2221-E-239-003"],"award-info":[{"award-number":["MOST 108-2221-E-150-041 and MOST 108-2221-E-239-003"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study developed a bipolar optical code division multiple access (Bi-OCDMA) technique based on spectral amplitude coding for the formation and transmission of optical-polarized and coded signals over wireless optical channels. Compared with conventional Bi-OCDMA schemes, the proposed free-space optics communication system that uses a dual electro-optical modulator design improves the transmission rate. In theory, multiple access interference can be removed by using correlation subtraction schemes. The experiment results revealed that the proposed system can be employed to accurately extract codewords from an M-sequence and subsequently reconstruct the desired original data. Moreover, the proposed architecture can be implemented easily in simple and cost-effective designs and may be beneficial for broadening the use of Bi-OCDMA schemes in wireless optical communications.<\/jats:p>","DOI":"10.3390\/s20123583","type":"journal-article","created":{"date-parts":[[2020,6,24]],"date-time":"2020-06-24T10:54:59Z","timestamp":1592996099000},"page":"3583","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Bipolar Optical Code Division Multiple Access Techniques Using a Dual Electro-Optical Modulator Implemented in Free-Space Optics Communications"],"prefix":"10.3390","volume":"20","author":[{"given":"Shin-Pin","family":"Tseng","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, National United University, Miaoli 36003, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1214-6256","authenticated-orcid":false,"given":"Eddy","family":"Wijanto","sequence":"additional","affiliation":[{"name":"Department of Electro-Optical Engineering, National Formosa University, Yunlin 632, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Po-Han","family":"Lai","sequence":"additional","affiliation":[{"name":"Department of Electro-Optical Engineering, National Formosa University, Yunlin 632, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hsu-Chih","family":"Cheng","sequence":"additional","affiliation":[{"name":"Department of Electro-Optical Engineering, National Formosa University, Yunlin 632, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Ahmed, A., Singh, A., and Kaur, S. (2019, January 7\u20138). Performance analysis of WDM-MIMO free space optical system under atmospheric turbulence. Proceedings of the 6th International Conference on Signal Processing and Integrated Networks (SPIN), Noida, India.","DOI":"10.1109\/SPIN.2019.8711685"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"S14","DOI":"10.1109\/MCOM.2014.6736740","article-title":"Toward reliable hybrid WDM\/TDM passive optical networks","volume":"52","author":"Mahloo","year":"2014","journal-title":"IEEE Commun. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1109\/TBC.2019.2901412","article-title":"High-capacity 5G fronthaul networks based on optical space division multiplexing","volume":"65","author":"Rommel","year":"2019","journal-title":"IEEE Trans. Broadcast."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Li, Q., Xu, S., Yu, J., Yan, L., and Huang, Y. (2019). An improved method for the position detection of a quadrant detector for free space optical communication. Sensors, 19.","DOI":"10.3390\/s19010175"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2518","DOI":"10.1109\/JSEN.2011.2128308","article-title":"Wavelength division multiplexing\/spectral amplitude coding applications in fiber vibration sensor systems","volume":"11","author":"Cheng","year":"2011","journal-title":"IEEE Sens. J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1049\/el:19990210","article-title":"Programmable high-speed optical code recognition using fiber Bragg grating arrays","volume":"35","author":"Hunter","year":"1999","journal-title":"Electron. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1109\/50.50743","article-title":"Coherent ultrashort light pulse code-division multiple access communication systems","volume":"8","author":"Salehi","year":"1990","journal-title":"IEEE J. Light. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5062","DOI":"10.1109\/JLT.2015.2495334","article-title":"Theoretical studies of ultrashort light pulse spectrally-phase-encoded OCDMA system using power-cubic optical nonlinear preprocessor","volume":"33","author":"Zefreh","year":"2015","journal-title":"IEEE J. Light. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Sikder, S., Sarkar, M., and Ghosh, S. (2017, January 22\u201323). Optical network security using unipolar Walsh code. In AIP Conference Proceedings, Secunderabad, India.","DOI":"10.1063\/1.5032061"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1364\/JOCN.10.000035","article-title":"Reducing inter-core crosstalk impact via code-interleaving and bipolar 2-PPM for core-multiplexed SAC OCDMA PON","volume":"10","author":"Farghal","year":"2018","journal-title":"J. Opt. Commun. Netw."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"045004","DOI":"10.1117\/1.2188416","article-title":"Complementary bipolar spectral polarization coding over fiber-grating-based differential photo detectors","volume":"45","author":"Chang","year":"2006","journal-title":"Opt. Eng."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1508","DOI":"10.1109\/JSTQE.2007.897604","article-title":"Sequence-inversion-keyed optical CDMA coding\/decoding scheme using an electrooptic phase modulator and fiber Bragg grating arrays","volume":"13","author":"Zeng","year":"2007","journal-title":"IEEE J. Sel. Top. Quant."},{"key":"ref_13","first-page":"493","article-title":"Novel bipolar reconfigurable code for OCDMA network","volume":"5","author":"Patel","year":"2018","journal-title":"Int. J. Adv. Eng. Res. Dev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1080\/01468030.2019.1701752","article-title":"Sensors of encoding and decoding based on superstructure fiber Bragg gratings modulated in amplitude and phase for applications in systems OCDMA-63 chip","volume":"38","author":"Filho","year":"2019","journal-title":"Fiber Integr. Opt."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1007\/s11235-019-00610-7","article-title":"Spectral coded phase bipolar OCDMA technological implementation thanks to low index modulation filters","volume":"73","author":"Ghoumid","year":"2020","journal-title":"Telecommun. Syst."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Ahmed, M.S., and Glesk, I. (2018). Application of semiconductor optical amplifier (SOA) in managing chirp of optical code division multiple access (OCDMA) code carriers in temperature affected fibre link. App. Sci., 8.","DOI":"10.3390\/app8050715"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Chen, K.S., Chen, Y.C., and Liao, L.G. (2018). Advancing high-speed transmissions over OCDMA networks by employing an intelligently structured receiver for noise mitigation. Appl. Sci., 8.","DOI":"10.3390\/app8122408"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Yen, C.T., Huang, J.F., and Zhang, W.Z. (2018). Hiding stealth optical CDMA signals in public BPSK channels for optical wireless communication. Appl. Sci., 8.","DOI":"10.20944\/preprints201808.0367.v1"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1049\/el:20083321","article-title":"Extended M-sequence codes for SAC FO-CDMA PONs applications","volume":"44","author":"Tseng","year":"2008","journal-title":"Electron. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1016\/j.yofte.2013.10.001","article-title":"Employing optical code division multiple access technology in the all fiber loop vibration sensor system","volume":"19","author":"Tseng","year":"2013","journal-title":"Opt. Fiber Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"83511","DOI":"10.1109\/ACCESS.2020.2991071","article-title":"Multiple access techniques for bipolar optical code division in wireless optical communications","volume":"8","author":"Cheng","year":"2020","journal-title":"IEEE Access"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/12\/3583\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:42:32Z","timestamp":1760175752000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/12\/3583"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,24]]},"references-count":21,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,6]]}},"alternative-id":["s20123583"],"URL":"https:\/\/doi.org\/10.3390\/s20123583","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2020,6,24]]}}}