Integrated contra-directionally coupled chirped Bragg grating waveguide with a linear group delay spectrum

Abstract

Due to the advantages of low propagation loss, wide operation bandwidth, continuous delay tuning, fast tuning speed, and compact footprints, chirped Bragg grating waveguide has great application potential in wideband phased array beamforming systems. However, the disadvantage of large group delay error hinders their practical applications. The nonlinear group delay spectrum is one of the main factors causing large group delay errors. To solve this problem, waveguides with nonlinear gradient widths are adopted in this study to compensate for the nonlinear effect of the grating apodization on the mode effective index. As a result, a linear group delay spectrum is obtained in the experiment, and the group delay error is halved.

Graphical abstract

Keywords

Bragg gratings / Silicon photonics / True time delay

References

[1] Yang, H. , Yun, B. : A six bit silicon nitride optical true time delay line for Ka-band phased array antenna. J. Phys. Conf. Ser. 1634 (1), 012173 (2020)

[2] Jeong, J. , Yom, I. , Kim, J. , Lee, W. , Lee, C.A. : 6-18-GHz GaAs multifunction chip with 8-bit true time delay and 7-bit amplitude control. IEEE Trans. Microw. Theory Tech. 66 (5), 2220- 2230 (2018)

[3] Choo, G. , Madsen, C.K. , Palermo, S. , Entesari, K. : Automatic monitor-based tuning of an RF silicon photonic 1×4 asymmetric binary tree true-time-delay beamforming network. J. Lightwave Technol. 36 (22), 5263- 5275 (2018)

[4] Ye, X. , Zhang, F. , Pan, S. : Compact optical true time delay beam-former for a 2D phased array antenna using tunable dispersive elements. Opt. Lett. 41 (17), 3956- 3959 (2016)

[5] Wang, C. , Zhang, M. , Chen, X. , Bertrand, M. , Shams-Ansari, A. , Chandrasekhar, S. , Winzer, P. , Lončar, M. : Integrated lithium niobate electro-optic modulators operating at CMOS-compatible voltages. Nature 562 (7725), 101- 104 (2018)

[6] He, M. , Xu, M. , Ren, Y. , Jian, J. , Ruan, Z. , Xu, Y. , Gao, S. , Sun, S. , Wen, X. , Zhou, L. , Liu, L. , Guo, C. , Chen, H. , Yu, S. , Liu, L. , Cai, X. : High-performance hybrid silicon and lithium niobate Mach-Zehnder modulators for 100 Gbit· s^-1 and beyond. Nat. Photonics 13 (5), 359- 364 (2019)

[7] Lischke, S. , Peczek, A. , Morgan, J.S. , Sun, K. , Steckler, D. , Yamamoto, Y. , Korndörfer, F. , Mai, C. , Marschmeyer, S. , Fraschke, M. , Krüger, A. , Beling, A. , Zimmermann, L. : Ultra-fast germanium photodiode with 3-dB bandwidth of 265 GHz. Nat. Photonics 16 (3), 925- 931 (2022)

[8] Li, M. , Zhu, N. : Recent advances in microwave photonics. Front. Optoelectron. 9 (2), 160- 185 (2016)

[9] Xie, J. , Zhou, L. , Li, Z. , Wang, J. , Chen, J. : Seven-bit reconfigurable optical true time delay line based on silicon integration. Opt. Express 22 (19), 22707- 22715 (2014)

[10] Wang, X. , Zhou, L. , Li, R. , Xie, J. , Lu, L. , Wu, K. , Chen, J. : Continuously tunable ultra-thin silicon waveguide optical delay line. Optica 4 (5), 507- 515 (2017)

[11] Song, L. , Chen, T. , Liu, W. , Liu, H. , Peng, Y. , Yu, Z. , Li, H. , Shi, Y. , Dai, D. : Toward calibration-free Mach-Zehnder switches for next-generation silicon photonics. Photon. Res. 10 (3), 793- 801 (2022)

[12] Xiang, C. , Davenport, M.L. , Khurgin, J.B. , Morton, P.A. , Bowers, J.E. : Low-loss continuously tunable optical true time delay based on Si₃N₄ ring resonators. IEEE J. Sel. Top. Quantum Electron. 24 (4), 5900109 (2018)

[13] Lin, D. , Xu, X. , Zheng, P. , Yang, H. , Hu, G. , Yun, B. , Cui, Y. : A tunable optical delay line based on cascaded silicon nitride microrings for Ka-band beamforming. IEEE Photonics J. 11 (5), 5503210 (2019)

[14] Chung, C. , Xu, X. , Wang, G. , Pan, Z. , Chen, R.T. : On-chip optical true time delay lines featuring one-dimensional fishbone photonic crystal waveguide. Appl. Phys. Lett. 112 (7), 071104 (2018)

[15] Cassan, E. , Roux, X.L. , Caer, C. , Hao, R. , Bernier, D. , Marris-Morini, D. , Vivien, L. : Silicon slow light photonic crystals structures: present achievements and future trends. Front. Optoelectron. China 4 (3), 243- 253 (2011)

[16] Kaushal, S. , Cheng, R. , Ma, M. , Mistry, A. , Burla, M. , Chrostowski, L. , Azaña, J. : Optical signal processing based on silicon photonics waveguide Bragg gratings. Front Optoelectron. 11 (2), 163- 188 (2018)

[17] Du, Z. , Xiang, C. , Fu, T. , Chen, M. , Yang, S. , Bowers, J.E. , Chen, H. : Silicon nitride chirped spiral Bragg gratings with large group delay. APL Photonics 5 (10), 101302 (2020)

[18] Ortega, B. , Mora, J. , Chulia, R. : Optical beamformer for 2-D phased array antenna with subarray partitioning capability. IEEE Photonics J. 8 (3), 6600509 (2016)

[19] Gao, X. , Zhu, Y. , Chong, Y. , Xu, Z. , Mei, L. , Cao, J. , Zhang, F. , Dong, J. : Integrated channel-shared optical true time delay line array based on gratings-assisted contradirectional couplers for phased array antennas. Proc. SPIE 11763, 117633W (2021)

[20] Sun, Y. , Wang, D. , Deng, C. , Lu, M. , Huang, L. , Hu, G. , Yun, B. , Zhang, R. , Li, M. , Dong, J. , Wang, A. , Cui, Y. : Large group delay in silicon-on-insulator chirped spiral Bragg gratings waveguide. IEEE Photonics J. 13 (5), 5500205 (2021)

[21] Shi, W. , Veerasubramanian, V. , Patel, D. , Plant, D.V. : Tunable nanophotonic delay lines using linearly chirped contradirectional couplers with uniform Bragg gratings. Opt. Lett. 39 (3), 701- 703 (2014)

[22] Wang, X. , Zhao, Y. , Ding, Y. , Xiao, S. , Dong, J. : Tunable optical delay line based on integrated gratings-assisted contradirectional couplers. Photon. Res. 6 (9), 880- 886 (2018)

[23] Zhang, F. , Dong, J. , Zhu, Y. , Gao, X. , Zhang, X. : Integrated optical true time delay network based on gratings-assisted contradirectional couplers for phased array antennas. IEEE J. Sel. Top. Quantum Electron. 26 (5), 8302407 (2020)

RIGHTS & PERMISSIONS

2023 The Author(s)