[1] Y. I. A. Al-Yasir, N. Ojaroudi Parchin, R. A. Abd-Alhameed, A. M. Abdulkhaleq, J. M. Noras. Recent progress in the design of 4g/5g reconfigurable filters. Electronics, 8, 114(2019).
[2] R. Levy, S. B. Cohn. A history of microwave filter research, design, and development. IEEE Trans. Microw. Theory Tech., 32, 1055-1067(1984).
[3] J. Xu, K. Bi, X. Zhai, Y. Hao, K. D. Mcdonald-Maier. A dual-band microwave filter design for modern wireless communication systems. IEEE Access, 7, 98786-98791(2019).
[4] C. Liu, J. Wang, L. Cheng, M. Zhu, G.-K. Chang. Key microwave-photonics technologies for next-generation cloud-based radio access networks. J. Lightwave Technol., 32, 3452-3460(2014).
[5] W. Saad, M. Bennis, M. Chen. A vision of 6g wireless systems: Applications, trends, technologies, and open research problems. IEEE Netw., 34, 134-142(2019).
[6] J. Wang, C. Jiang, H. Zhang, Y. Ren, K.-C. Chen, L. Hanzo. Thirty years of machine learning: the road to Pareto-optimal wireless networks. IEEE Commun. Surv. Tutorials, 22, 1472-1514(2020).
[7] X. Li, F. Dong, S. Zhang, W. Guo. A survey on deep learning techniques in wireless signal recognition. Wireless Commun. Mobile Comput., 2019, 5629572(2019).
[8] Y. Zhao, X. Luo, X. Lin, H. Wang, X. Kui, F. Zhou, J. Wang, Y. Chen, W. Chen. Visual analytics for electromagnetic situation awareness in radio monitoring and management. IEEE Trans. Vis. Comput. Graphics, 26, 590-600(2019).
[9] A. Goldsmith. Wireless Communication(2005).
[10] S. Haykin. Cognitive radio: brain-empowered wireless communications. IEEE J. Sel. Areas Commun., 23, 201-220(2005).
[11] Z. Wang, Y. Du, K. Wei, K. Han, X. Xu, G. Wei, W. Tong, P. Zhu, J. Ma, J. Wang, G. Wang. Vision, application scenarios, and key technology trends for 6G mobile communications. Sci. China Inf. Sci., 65, 151301(2022).
[12] D. Marpaung, J. Yao, J. Capmany. Integrated microwave photonics. Nat. Photonics, 13, 80-90(2019).
[13] J. Capmany, D. Novak. Microwave photonics combines two worlds. Nat. Photonics, 1, 319-330(2007).
[14] E. J. Naglich, J. Lee, D. Peroulis, W. J. Chappell. A tunable bandpass-to-bandstop reconfigurable filter with independent bandwidths and tunable response shape. IEEE Trans. Microw. Theory Tech., 58, 3770-3779(2010).
[15] I. F. Akyildiz, A. Kak, S. Nie. 6G and beyond: the future of wireless communications systems. IEEE Access, 8, 133995(2020).
[16] M. Z. Chowdhury, M. Shahjalal, M. K. Hasan, Y. M. Jang. The role of optical wireless communication technologies in 5G/6G and IoT solutions: prospects, directions, and challenges. Appl. Sci., 9, 4367(2019).
[17] Q. Long, Y. Chen, H. Zhang, X. Lei. Software defined 5G and 6G networks: a survey. Mobile Netw. Appl., 27, 1792-1812(2022).
[18] A. Boutejdar, A. A. Ibrahim, W. A. E. Ali. Design of compact size and tunable band pass filter for WLAN applications. Electron. Lett., 52, 1996-1997(2016).
[19] E. J. Naglich, A. C. Guyette, D. Peroulis. High-Q intrinsically-switched quasi-absorptive tunable bandstop filter with electrically-short resonators. IEEE MTT-S International Microwave Symposium (IMS), 1-4(2014).
[20] S. Courreges, Y. Li, Z. Zhao, K. Choi, A. Hunt, S. Horst, J. D. Cressler, J. Papapolymerou. A Ka-band electronically tunable ferroelectric filter. IEEE Microw. Wireless Compon. Lett., 19, 356-358(2009).
[21] Y. Liu, A. Choudhary, D. Marpaung, B. J. Eggleton. Integrated microwave photonic filters. Adv. Opt. Photon., 12, 485-555(2020).
[22] S. Pan, Y. Zhang. Microwave photonic radars. J. Lightwave Technol., 38, 5450-5484(2020).
[23] W. Zhang, J. Yao. Silicon-based integrated microwave photonics. IEEE J. Quantum Electron., 52, 0600412(2015).
[24] D. Marpaung, C. Roeloffzen, R. Heideman, A. Leinse, S. Sales, J. Capmany. Integrated microwave photonics. Laser Photon. Rev., 7, 506-538(2013).
[25] S. X. Chew, X. Yi, S. Song, L. Li, P. Bian, L. Nguyen, R. A. Minasian. Silicon-on-insulator dual-ring notch filter for optical sideband suppression and spectral characterization. J. Lightwave Technol., 34, 4705-4714(2016).
[26] S. Song, S. X. Chew, X. Yi, L. Nguyen, R. A. Minasian. Tunable single-passband microwave photonic filter based on integrated optical double notch filter. J. Lightwave Technol., 36, 4557-4564(2018).
[27] W. Jiao, M. Cheng, K. Wang, J. Sun. Demonstration of photonic-assisted microwave frequency measurement using a notch filter on silicon chip. J. Lightwave Technol., 39, 6786-6795(2021).
[28] M. Burla, X. Wang, M. Li, L. Chrostowski, J. Azaña. Wideband dynamic microwave frequency identification system using a low-power ultracompact silicon photonic chip. Nat. Commun., 7, 13004(2016).
[29] X. Guo, T. Dai, B. Chen, H. Yu, Y. Wang, J. Yang. Twin-Fano resonator with widely tunable slope for ultra-high-resolution wavelength monitor. Opt. Lett., 44, 4527-4530(2019).
[30] J. Xu, Y. Zhang, X. Guo, Q. Huang, X. Zhang, Y. Su. Ultra-narrow passband-tunable filter based on a high-q silicon racetrack resonator. Opt. Lett., 46, 5575-5578(2021).
[31] L. Zhang, L. Jie, M. Zhang, Y. Wang, Y. Xie, Y. Shi, D. Dai. Ultrahigh-Q silicon racetrack resonators. Photon. Res., 8, 684-689(2020).
[32] Z. Tao, B. Wang, B. Bai, R. Chen, H. Shu, X. Zhang, X. Wang. An ultra-compact polarization-insensitive slot-strip mode converter. Front. Optoelectron., 15, 1(2022).
[33] D. Thomson, A. Zilkie, J. E. Bowers, T. Komljenovic, G. T. Reed, L. Vivien, D. Marris-Morini, E. Cassan, L. Virot, J.-M. Fédéli, J. Hartmann. Roadmap on silicon photonics. J. Opt., 18, 073003(2016).
[34] F. Kish, V. Lal, P. Evans, S. W. Corzine, M. Ziari, T. Butrie, M. Reffle, H.-S. Tsai, A. Dentai, J. Pleumeekers, M. Missey. System-on-chip photonic integrated circuits. IEEE J. Sel. Top. Quantum Electron., 24, 6100120(2017).
[35] D. Marpaung, B. Morrison, M. Pagani, R. Pant, D.-Y. Choi, B. Luther-Davies, S. J. Madden, B. J. Eggleton. Low-power, chip-based stimulated Brillouin scattering microwave photonic filter with ultrahigh selectivity. Optica, 2, 76-83(2015).
[36] B. J. Eggleton, C. G. Poulton, P. T. Rakich, M. J. Steel, G. Bahl. Brillouin integrated photonics. Nat. Photonics, 13, 664-677(2019).
[37] L. Zhang, S. Hong, Y. Wang, H. Yan, Y. Xie, T. Chen, M. Zhang, Z. Yu, Y. Shi, L. Liu, D. Dai. Ultralow-loss silicon photonics beyond the singlemode regime. Laser Photon. Rev., 16, 2100292(2022).
[38] Y. Liu, A. Choudhary, G. Ren, K. Vu, B. Morrison, A. Casas-Bedoya, T. G. Nguyen, D.-Y. Choi, P. Ma, A. Mitchell, S. J. Madden, D. Marpaung, B. J. Eggleton. Integration of Brillouin and passive circuits for enhanced radio-frequency photonic filtering. APL Photon., 4, 106103(2019).
[39] S. Gertler, N. T. Otterstrom, M. Gehl, A. L. Starbuck, C. M. Dallo, A. T. Pomerene, D. C. Trotter, A. L. Lentine, P. T. Rakich. Narrowband microwave-photonic notch filters using Brillouin-based signal transduction in silicon. Nat. Commun., 13, 1947(2022).
[40] M. Garrett, Y. Liu, M. Merklein, D.-Y. Choi, K. Yan, S. J. Madden, B. J. Eggleton. Multi-band and frequency-agile chip-based RF photonic filter for ultra-deep interference rejection. J. Lightwave Technol., 40, 1672-1680(2022).
[41] S. Gertler, E. A. Kittlaus, N. T. Otterstrom, P. T. Rakich. Tunable microwave-photonic filtering with high out-of-band rejection in silicon. APL Photon., 5, 096103(2020).
[42] X. Liu, Y. Yu, H. Tang, L. Xu, J. Dong, X. Zhang. Silicon-on-insulator-based microwave photonic filter with narrowband and ultrahigh peak rejection. Opt. Lett., 43, 1359-1362(2018).
[43] L. Zhuang, C. G. H. Roeloffzen, M. Hoekman, K.-J. Boller, A. J. Lowery. Programmable photonic signal processor chip for radiofrequency applications. Optica, 2, 854-859(2015).
[44] V. R. Supradeepa, C. M. Long, R. Wu, F. Ferdous, E. Hamidi, D. E. Leaird, A. M. Weiner. Comb-based radiofrequency photonic filters with rapid tunability and high selectivity. Nat. Photonics, 6, 186-194(2012).
[45] D. Pérez, I. Gasulla, L. Crudgington, D. J. Thomson, A. Z. Khokhar, K. Li, W. Cao, G. Z. Mashanovich, J. Capmany. Multipurpose silicon photonics signal processor core. Nat. Commun., 8, 1(2017).
[46] H. Shu, L. Chang, Y. Tao, B. Shen, W. Xie, M. Jin, A. Netherton, Z. Tao, X. Zhang, R. Chen, B. Bai, J. Qin, S. Yu, X. Wang, J. E. Bowers. Microcomb-driven silicon photonic systems. Nature, 605, 457-463(2022).
[47] J. Hu, J. He, J. Liu, A. S. Raja, M. Karpov, A. Lukashchuk, T. J. Kippenberg, C.-S. Brès. Reconfigurable radiofrequency filters based on versatile soliton microcombs. Nat. Commun., 11, 1(2020).
[48] E. Hamidi, D. E. Leaird, A. M. Weiner. Tunable programmable microwave photonic filters based on an optical frequency comb. IEEE Trans. Microw. Theory Tech., 58, 3269-3278(2010).
[49] Y. Tao, H. Shu, X. Wang, M. Jin, Z. Tao, F. Yang, J. Shi, J. Qin. Hybrid-integrated high-performance microwave photonic filter with switchable response. Photon. Res., 9, 1569-1580(2021).
[50] J. S. Fandiño, P. Muñoz, D. Doménech, J. Capmany. A monolithic integrated photonic microwave filter. Nat. Photonics, 11, 124-129(2017).
[51] W. Zhang, J. Yao. On-chip silicon photonic integrated frequency-tunable bandpass microwave photonic filter. Opt. Lett., 43, 3622-3625(2018).
[52] W. Li, N. H. Zhu, L. X. Wang. Continuously tunable microwave photonic notch filter with a complex coefficient. IEEE Photon. J., 3, 462-467(2011).
[53] W. Bogaerts, P. De Heyn, T. Van Vaerenbergh, K. De Vos, S. Kumar Selvaraja, T. Claes, P. Dumon, P. Bienstman, D. Van Thourhout, R. Baets. Silicon microring resonators. Laser Photon. Rev., 6, 47-73(2012).
[54] H. Chi, X. Zou, J. Yao. Analytical models for phase-modulation-based microwave photonic systems with phase modulation to intensity modulation conversion using a dispersive device. J. Lightwave Technol., 27, 511-521(2009).
[55] W. Li, M. Li, J. Yao. A narrow-passband and frequency-tunable microwave photonic filter based on phase-modulation to intensity-modulation conversion using a phase-shifted fiber Bragg grating. IEEE Trans. Microw. Theory Tech., 60, 1287-1296(2012).
[56] W. Liu, W. Zhang, J. Yao. A bandstop microwave photonic delay-line filter with both tunable stop-band rejection ratio and tunable frequency. IEEE MTT-S International Microwave Symposium, 1-3(2015).
[57] B. A. Adoum, W. P. Wen. Investigation of band-stop to all pass reconfigurable filter. 4th International Conference on Intelligent and Advanced Systems (ICIAS), 1, 190-193(2012).
[58] Y. Long, J. Xia, Y. Zhang, J. Dong, J. Wang. Photonic crystal nanocavity assisted rejection ratio tunable notch microwave photonic filter. Sci. Rep., 7, 1(2017).
[59] A. A. Ibrahim, W. A. E. Ali, M. A. Abdelghany. Design of dual-band dual-mode band-pass filter utilizing 0° feed structure and lumped capacitors for WLAN/WIMAX applications. Electronics, 9, 1697(2020).
[60] Y. Liu, J. Hotten, A. Choudhary, B. J. Eggleton, D. Marpaung. All-optimized integrated RF photonic notch filter. Opt. Lett., 42, 4631-4634(2017).
[61] H. Yang, J. Li, P. Zheng, G. Hu, B. Yun, Y. Cui. A stopband and passband switchable microwave photonic filter based on integrated dual ring coupled Mach–Zehnder interferometer. IEEE Photon. J., 11, 5502608(2019).
[62] X. Zou, F. Zou, Z. Cao, B. Lu, X. Yan, G. Yu, X. Deng, B. Luo, L. Yan, W. Pan, J. Yao. A multifunctional photonic integrated circuit for diverse microwave signal generation, transmission, and processing. Laser Photon. Rev., 13, 1800240(2019).
[63] X. Guo, Y. Liu, T. Yin, B. Morrison, M. Pagani, O. Daulay, W. Bogaerts, B. J. Eggleton, A. Casas-Bedoya, D. Marpaung. Versatile silicon microwave photonic spectral shaper. APL Photon., 6, 036106(2021).
[64] S. Dang, O. Amin, B. Shihada, M.-S. Alouini. What should 6G be?. Nat. Electron., 3, 20-29(2020).
[65] C. Han, M. Jin, Y. Tao, B. Shen, H. Shu, X. Wang. Ultra-compact silicon modulator with 110 GHz bandwidth. Optical Fiber Communication Conference, Th4C-5(2022).
[66] S. Lischke, A. Peczek, J. S. Morgan, K. Sun, D. Steckler, Y. Yamamoto, F. Korndörfer, C. Mai, S. Marschmeyer, M. Fraschke, A. Krüger, A. Beling, L. Zimmermann. Ultra-fast germanium photodiode with 3-dB bandwidth of 265 GHz. Nat. Photonics, 15, 925-931(2021).
[67] C. Wang, M. Zhang, X. Chen, M. Bertrand, A. Shams-Ansari, S. Chandrasekhar, P. Winzer, M. Lončar. Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages. Nature, 562, 101-104(2018).
[68] J. Li, P. Zheng, G. Hu, R. Zhang, B. Yun, Y. Cui. Performance improvements of a tunable bandpass microwave photonic filter based on a notch ring resonator using phase modulation with dual optical carriers. Opt. Express, 27, 9705-9715(2019).
[69] Y. Zhang, H. Zhang, J. Zhang, J. Liu, L. Wang, D. Chen, N. Chi, X. Xiao, S. Yu. 240 Gb/s optical transmission based on an ultrafast silicon microring modulator. Photon. Res., 10, 1127-1133(2022).
[70] Y. Wei, J. Cheng, Y. Wang, H. Zhou, J. Dong, D. Huang, F. Li, M. Li, P. K. A. Wai, X. Zhang. Fast-response silicon photonic microheater induced by parity-time symmetry breaking. Adv. Photon. Res., 3, 2200120(2021).
[71] Y. Liu, Z. Qiu, X. Ji, A. Lukashchuk, J. He, J. Riemensberger, M. Hafermann, R. N. Wang, J. Liu, C. Ronning, T. J. Kippenberg. A photonic integrated circuit–based erbium-doped amplifier. Science, 376, 1309-1313(2022).
[72] J. Rönn, W. Zhang, A. Autere, X. Leroux, L. Pakarinen, C. Alonso-Ramos, A. Säynätjoki, H. Lipsanen, L. Vivien, E. Cassan, Z. Sun. Ultra-high on-chip optical gain in erbium-based hybrid slot waveguides. Nat. Commun., 10, 1(2019).
[73] Z. Chen, H. Gao, D. Leenaerts, D. Milosevic, P. Baltus. A 29–37 GHz BICMOS low-noise amplifier with 28.5 dB peak gain and 3.1–4.1 dB NF. IEEE Radio Frequency Integrated Circuits Symposium (RFIC), 288-291(2018).
[74] X. Tong, S. Zhang, P. Zheng, Y. Huang, J. Xu, X. Shi, R. Wang. A 22–30-GHz GAN low-noise amplifier with 0.4–1.1-dB noise figure. IEEE Microw. Wireless Compon. Lett., 29, 134-136(2019).
[75] M. Božanić, S. Sinha. Millimeter-Wave Low Noise Amplifiers(2018).
[76] L. Xu, J. Hou, H. Tang, Y. Yu, Y. Yu, X. Shu, X. Zhang. Silicon-on-insulator-based microwave photonic filter with widely adjustable bandwidth. Photon. Res., 7, 110-115(2019).
[77] C. G. Bottenfield, V. A. Thomas, S. E. Ralph. Silicon photonic modulator linearity and optimization for microwave photonic links. IEEE J. Sel. Top. Quantum Electron., 25, 3400110(2019).
[78] V. J. Urick, K. J. Williams, J. D. McKinney. Fundamentals of Microwave Photonics(2015).
[79] M. Yu, D. Barton, R. Cheng, C. Reimer, P. Kharel, L. He, L. Shao, D. Zhu, Y. Hu, H. R. Grant, L. Johansson, Y. Okawachi, A. L. Gaeta, M. Zhang, M. Lončar. Integrated femtosecond pulse generator on thin-film lithium niobate. Nature, 612, 252-258(2022).
