[3] Tang W J, Chu T. Research progress in silicon optical switching devices (invited)[J]. Acta Optica Sinica, 44, 1513016(2024).

[4] Li Y C, Ouyang K G, Guo N N et al. Ultra-low loss fiber deployment in elastic optical networks with fixed and variable topologies[J]. Journal of Lightwave Technology, 42, 3515-3530(2024).

[5] Rademacher G, Luís R S, Puttnam B J et al. A comparative study of few-mode fiber and coupled-core multi-core fiber transmission[J]. Journal of Lightwave Technology, 40, 1590-1596(2022).

[6] Hazarika P, Buglia H, Jarmolovičius M et al. Multi-band transmission over E-, S-, C- and L-band with a hybrid Raman amplifier[J]. Journal of Lightwave Technology, 42, 1215-1224(2024).

[7] Liu S K, Chu Y B, Dai N L et al. Bismuth erbium co‑doped fiber for C+L+U‑band ultra‑wideband amplification[J]. Chinese Journal of Lasers, 51, 1406004(2024).

[8] Han S D, Li Y C, Shen G X et al. Scheduled lightpath demand provisioning in fiber space division multiplexing optical networks[J]. Journal of Optical Communications and Networking, 17, 110-126(2025).

[9] Kuno T, Mori Y, Subramaniam S et al. Design and evaluation of a reconfigurable optical add-drop multiplexer with flexible wave-band routing in SDM networks[J]. Journal of Optical Communications and Networking, 14, 248-256(2022).

[10] Deng N, Zong L J, Jiang H Y et al. Challenges and enabling technologies for multi-band WDM optical networks[J]. Journal of Lightwave Technology, 40, 3385-3394(2022).

[11] Teng Y R, Yang R Z, Zhang N et al. Multi-core fiber based filterless space-division multiplexing (SDM) networks with adaptive network topologies[C], 1022-1025(2024).

[12] Suzuki K, Ota M, Morimoto Y et al. Double-decker CDC-ROADM node for multi-band network with wavelength band granularity[C], 1-3(2024).

[13] Strasser T A, Wagener J L. Wavelength-selective switches for ROADM applications[J]. IEEE Journal of Selected Topics in Quantum Electronics, 16, 1150-1157(2010).

[14] Collings B C. Advanced ROADM technologies and architectures[C], 1-3(2015).

[15] Simmons J M. Optical network design and planning[M]. Monarch network architects, 38-50(2014).

[16] Lumentum. Optical communications products[EB/OL]. https:∥www.lumentum.com/en/optical-communica-tions/all-products

[17] Yang H N, Wilkinson P, Robertson B et al. 24 [1×12] wavelength selective switches integrated on a single 4k LCoS device[J]. Journal of Lightwave Technology, 39, 1033-1039(2021).

[18] Yang H N, Robertson B, Wilkinson P et al. Small phase pattern 2D beam steering and a single LCOS design of 40 1×12 stacked wavelength selective switches[J]. Optics Express, 24, 12240-12253(2016).

[19] de Hennin S, Wall P, Moffat S H et al. Addressing manufacturability and reliability of MEMS-based WSS[C], 1-3(2007).

[20] Li S H, Wan Z J, Xu J et al. Wavelength-selective switch based on a polarization-independent transmission grating and a high fill-factor micromirror array[J]. IEEE Photonics Technology Letters, 23, 1249-1251(2011).

[21] Seno K, Nemoto N, Yamaguchi K et al. Wavelength selective devices for SDM applications based on SPOC platform[J]. Journal of Lightwave Technology, 40, 1764-1775(2021).

[22] Nakamura F, Asakura H, Suzuki K et al. Silicon based 1×M wavelength selective switch using arrayed waveguide gratings with fold-back waveguides[J]. Journal of Lightwave Technology, 39, 2413-2420(2021).

[23] Baxter G, Frisken S, Abakoumov D et al. Highly programmable wavelength selective switch based on liquid crystal on silicon switching elements[C], 5-10(2006).

[24] Wang M, Zong L J, Mao L et al. LCoS SLM study and its application in wavelength selective switch[J]. Photonics, 4, 22(2017).

[25] Stepanovsky M. A Comparative review of MEMS-based optical cross-connects for all-optical networks from the past to the present day[J]. IEEE Communications Surveys & Tutorials, 21, 2928-2946(2019).

[26] An Y, Sun B Q, Wang P et al. A 1×20 MEMS mirror array with large scan angle and low driving voltage for optical wavelength-selective switches[J]. Sensors and Actuators A: Physical, 324, 112689(2021).

[27] Ishii Y, Ikuma Y, Shikama K et al. Spatial and planar optical circuit (SPOC) technology and its application to photonic network devices[J]. NTT Technical Review, 14, 46-55(2016).

[28] Goh T, Kitoh T, Kohtoku M et al. Port scalable PLC-based wavelength selective switch with low extension loss for multi-degree ROADM/WXC[C], 1-3(2008).

[30] Finisar. Finisar Australia eeleases the world’s first flexgrid® Twin[EB/OL], 1-48. https:∥www.globenewswire.com/news-release/2021/10/04/2307857/0/en/Finisar-Australia-Releases-the-World-s-First-Flexgrid-Twin-1x48-Wavelength-Selective-Switch.html

[31] Finisar. Finisar Australia flexgrid® C+L band twin 65-port WSS honored by 2025 lightwave+BTR innovation reviews[EB/OL]. https:∥www.globenewswire.com/news-release/2025/03/10/3039759/0/en/Finisar-Australia-Flexgrid-C-L-band-Twin-65-Port-WSS-Honored-by-2025-Lightwave-BTR-Innovation-Reviews.html

[32] Gao Y S, Chen X, Chen G X et al. 1×25 LCOS-based wavelength selective switch with flexible passbands and channel selection[J]. Optical Fiber Technology, 45, 29-34(2018).

[33] Huang Z, Yang S, Zheng Z et al. Highly compact twin 1×35 wavelength selective switch[J]. Journal of Lightwave Technology, 41, 233-239(2022).

[34] Wang H, Liu M Q, Feng Z H et al. Design of LCoS-based twin 1×40 wavelength selective switch[J]. ZTE Communications, 22, 18-28(2024).

[35] Fukutoku M. Next generation ROADM technology and applications[C], 1-3(2015).

[36] Pedro J, Pato S. On scaling transport networks for very high nodal degree ROADM nodes using state-of-the-art optical switch technology[C], 1-5(2015).

[37] Pedro J, Pato S. ROADM express layer design strategies for scalable and cost-effective multi-fibre DWDM networks[C], 1-7(2017).

[38] Li Y C, Gao L, Shen G X et al. Impact of ROADM colorless, directionless, and contentionless (CDC) features on optical network performance[J]. Journal of Optical Communications and Networking, 4, B58-B67(2012).

[39] Ikuma Y, Suzuki K, Nemoto N et al. 8×24 wavelength selective switch for low-loss transponder aggregator[C], 1-3(2015).

[40] Li Y C, Zong L J, Gao M Y et al. Colorless, partially directional, and contentionless architecture for high-degree ROADMs[C], M4D.2-12(2020).

[41] Li Y C, Lin J M, Zong L J et al. Colorless, partially directionless, and contentionless architecture for high-degree ROADMs[J]. Journal of Optical Communications and Networking, 14, 481-492(2022).

[42] Sato K, Mori Y, Hasegawa H et al. Algorithm for raising OXC port count to meet traffic growth at minimum cost[J]. Journal of Optical Communications and Networking, 9, A263-A270(2017).

[43] Hashimoto R, Mori Y, Hasegawa H et al. Design of seamlessly and limitlessly expandable OXC and verification tests on its versatile applicability[J]. Journal of Optical Communications and Networking, 12, 99-108(2020).

[44] Ban T, Le H C, Hasegawa H et al. Evaluation of hardware requirements for large-scale OXC architecture employing wavelength switching and fiber selection[C], 1-2(2013).

[45] Ishida H, Hasegawa H, Sato K I. An efficient add/drop architecture for large-scale subsystem-modular OXC[C], 1-4(2013).

[46] Ishida H, Hasegawa H, Sato K I. Hardware scale and performance evaluation of a compact subsystem modular optical cross connect that adopts tailored add/drop architecture[J]. Journal of Optical Communications and Networking, 7, 586-595(2015).

[47] Niwa M, Mori Y, Hasegawa H et al. Tipping point for the future scalable OXC: what size MxM WSS is needed?[J]. Journal of Optical Communications and Networking, 9, A18-A25(2017).

[48] Tanaka Y, Hasegawa H, Sato K I. Criteria for selecting subsystem configuration in creating large-scale OXCs[J]. Journal of Optical Communications and Networking, 7, 1009-1017(2015).

[49] Yamakami S, Mori Y, Hasegawa H et al. Highly reliable and large-scale subsystem-modular optical cross-connect[J]. Optics Express, 25, 17982-17994(2017).

[50] Tanaka Y, Hasegawa H, Sato K I. Performance analysis of large-scale OXC that enables dynamic modular growth[J]. Optics Express, 23, 5994-6006(2015).

[51] Dai X C, He J Y, Li Y C et al. HMWC: a pay-as-you-grow high-dimension optical cross-connect (OXC) based on MEMSs and WSSs[C], 1-3(2024).

[52] Coherent. Coherent announces optical circuit switch for data centers[EB/OL]. https:∥www.coherent.com/news/press-releases/optical-circuit-switch-for-data-centers-live-demo-at-ofc-2024-based-on-ultrareliable-dlx-technology

[55] Mehrvar H, Hui X, Jun S et al. High degree ROADM cluster node[C], 1-3(2022).

[56] Mehrvar H, Li S Q, Bernier E. Dimensioning networks of high degree ROADMs[C], 1-3(2022).

[57] Zami T. Contention under heavy traffic load in a 224×224 wavelength-routing OXC made of smaller clustered sub-OXCs[C], 1106-1109(2022).

[58] Hashimoto R, Yamaoka S, Mori Y et al. First demonstration of subsystem-modular optical cross-connect using single-module 6×6 wavelength-selective switch[J]. Journal of Lightwave Technology, 36, 1435-1442(2018).

[59] Zong L J, Zhao H, Feng Z Y et al. 8×8 flexible wavelength cross-connect for CDC ROADM application[J]. IEEE Photonics Technology Letters, 27, 2603-2606(2015).

[60] Wu Y F, Chen R S, Xu J Q et al. A three-stage ROADM node architecture based on N×N partial wavelength selective switch[C], 1026-1028(2024).

[61] Lin J M, Chang T H, Zhai Z W et al. Wavelength selective switch-based clos network: blocking theory and performance analyses[J]. Journal of Lightwave Technology, 40, 5842-5853(2022).

[62] Lin J M, Chang Z S, Zong L J et al. From small to large: clos network for scaling all-optical switching[J]. IEEE Communications Magazine, 61, 136-141(2023).

[63] Zhai Z W, Lin J M, Li Y C et al. Delivering ring allreduce services in WSS-based all-optical rearrangeable clos network[C], 1-3(2021).

[64] Yang K X, Lin J M, Chang Z S et al. Service provisioning in WSS-based wavelength-convertible all-optical spine-leaf data center networks[C], 1-4(2023).

[65] Zhang B J, Zhang J W, Chang Z S et al. A parallel multi-grid high-degree OXC node architecture based on partial-WSS in a scaling multi-fiber network[C], W2A.47-3(2025).

[66] Hluchyj M G, Karol M J. Shuffle Net: an application of generalized perfect shuffles to multihop lightwave networks[J]. Journal of Lightwave Technology, 9, 1386-1397(1991).

[67] Jain N, Bhatele A, Ni X et al. Maximizing throughput on a dragonfly network[C], 336-347(2014).

[68] Andújar-Muñoz F J, Villar-Ortiz J A, Sánchez J L et al. N-dimensional twin torus topology[J]. IEEE Transactions on Computers, 64, 2847-2861(2015).

[69] Cheng Z Y, Ye T, Zhu Y X et al. A three-phase modularization approach of OXC for large-scale ROADM[J]. Journal of Lightwave Technology, 41, 7318-7327(2023).

[70] Yao Y B, Ye T, Deng N. Nonblocking conditions for flex-grid OXC-clos networks[C], 931-940(2024).

[71] Ye T, Luo J Y, Li H R et al. Design of large-scale OXC for the next-generation ROADM[C]. Republic of Korea, 1-2(2024).

[72] Meng E S, Li Y C, Lin J M et al. Service provisioning in WSS-based all-optical data center network with dragonfly topology[C], 1280-1283(2022).

[73] Lin J M, Shen G X, Zhai Z W et al. Delivering distributed machine learning services in all-optical datacenter networks with torus topology[C], 1-3(2021).

[74] Wang R K, Zhang Q L, Zhang J W et al. Multi-failure localization in high-degree ROADM-based optical networks using rules-informed neural networks[J]. IEEE Journal on Selected Areas in Communications, 43, 1738-1754(2025).