{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:16:08Z","timestamp":1760148968336,"version":"build-2065373602"},"reference-count":39,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2023,6,26]],"date-time":"2023-06-26T00:00:00Z","timestamp":1687737600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100010418","name":"Institute for Information &amp; Communications Technology Promotion(IITP)","doi-asserted-by":"publisher","award":["2021-0-00809"],"award-info":[{"award-number":["2021-0-00809"]}],"id":[{"id":"10.13039\/501100010418","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>It has been proposed to implement the &gt;100 Gb\/s data-center interconnects using a two-channel optical time-division multiplexed system with multilevel pulse-amplitude modulation. Unlike the conventional four-channel optical time-division multiplexed system which requires an expensive narrow pulse, the two-channel system can be implemented cost-effectively using a wide pulse (which can be simply generated using a single modulator). The two-channel system is expected to be practically available using an integrated transmitter in a chip due to the recent advances in photonics-integrated circuits. This paper reviews the current stage of research on a two-channel optical time-division multiplexed system and discusses possible research directions. Furthermore, it has been demonstrated that 200 Gb\/s signals can be generated by using modulators with only 17.2 GHz bandwidth. Therefore, the use of the phase-alternating pulse can make the multiplexed signal robust to chromatic dispersion, enabling the 200 Gb\/s 4-level pulse-amplitude-modulated signal to be transmitted over 1.9 km of standard single-mode fiber.<\/jats:p>","DOI":"10.3390\/s23135908","type":"journal-article","created":{"date-parts":[[2023,6,26]],"date-time":"2023-06-26T05:28:02Z","timestamp":1687757282000},"page":"5908","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Two-Channel OTDM System for Data-Center Interconnects: A Review"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4891-1490","authenticated-orcid":false,"given":"Sunghyun","family":"Bae","sequence":"first","affiliation":[{"name":"Department of Electronics Engineering, Kangwon National University, Samcheok 25913, Republic of Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0516-5811","authenticated-orcid":false,"given":"Hyeon-June","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Semiconductor Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2023,6,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1109\/JLT.2018.2793881","article-title":"Digital Signal Processing for Short-Reach Optical Communications: A Review of Current Technologies and Future Trends","volume":"36","author":"Zhong","year":"2018","journal-title":"J. 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