Advertisement

Comments on Zihang Zhu, Shanghong Zhao, Xuan Li, and Kun Qu, Tao Lin, “Photonic generation of frequency-octupled microwave signal with reduced electrical local oscillator power and improved spectrum purity” Opt. Quant. Electron (2017)

  • Mehedi HasanEmail author
  • Gazi Mahamud Hasan
  • Karin Hinzer
  • Trevor Hall
Article
  • 62 Downloads

Abstract

In the title paper, Zhu et al. presented a technique for generating filter less frequency octo-tupling signal based on a cascade of two dual-polarization modulators. Firstly, the harmonics of order 4\(l\) (\(l\) in an integer) are generated in the \(x\)-polarization by driving the x-modulators with an RF signal with a 90° phase difference between the two stages. Then the carrier is suppressed using unmodulated \(y\)-polarization by means of polarization multiplexing. Accordingly, the demerit of their design is the requirement to reset a precise polarizer angle to suppress the optical carrier every time there is a change in the RF drive amplitude or the modulation index. Nevertheless, the authors claim superior performance to a similar architecture in which the y-branch is modulated with the proper RF drive phases to suppress the carrier for all drive levels with no need to adjust a splitting ratio. The aim of this comment is to show that by modulating the \(y\)-polarization with adjusted RF drive phases, same architecture can be used to perform frequency octo-tupling whose performance is neither limited by precise settings of the polarizer angle nor by the proper settings of the modulation index. The carrier is suppressed for a unique value of the polarizer angle for all modulation index. If the modulation index is adjusted to suppress the \(4{\text{th}}\) harmonics, same circuit can be used to perform frequency 24-tupling generation.

Keywords

Microwave photonics Frequency octo-tupling Electro-optic modulator 

Notes

References

  1. Gao, Y., Wen, A., Jiang, W., Liang, D., Liu, W., Xiang, J.: Photonic microwave generation with frequency octo-tupling based on a DP-QPSK modulator. IEEE Photon. Technol. Lett. 27(21), 2260–2263 (2016)ADSCrossRefGoogle Scholar
  2. Hasan, M., Hall, T.J.: A photonic frequency octo-tupler with reduced RF drive power and extended spurious sideband suppression. Opt. Laser Technol. 81, 115–121 (2016a)ADSCrossRefGoogle Scholar
  3. Hasan, M., Hall, T.J.: Rebuttal to photonic microwave generation with frequency octo-tupling based on a DP-QPSK modulator. IEEE Photon. Technol. Lett. 28(16), 1794 (2016b)ADSCrossRefGoogle Scholar
  4. Hasan, M., Hall, T.J.: Comments on Xuan Li, Shanghong Zhao, Zihang Zhu, Bing Gong, Xingchun Chu, Yongjun Li, Jing Zhao and Yun Liu an optical millimeter-wave generation scheme based on two parallel dual-parallel Mach–Zehnder modulators and polarization multiplexing. J. Mod. Opt. 63(21), 2392–2395 (2016c)ADSCrossRefGoogle Scholar
  5. Hasan, M., Maldonado-Basilio, R., Lucarz, F., De Bougrenet, J.-L., Hall, T.J.: Photonic integrated circuit for frequency 8- and 24-tupled millimeter wave signal generation. Opt. Lett. 39(24), 6950–6953 (2014)ADSCrossRefGoogle Scholar
  6. Zhu, Z., Zhao, S., Li, X., Lin, K.Q.T.: Photonic generation of frequency-octupled microwave signal with reduced electrical local oscillator power and improved spectrum purity. Opt. Quant. Electron. (2017).  https://doi.org/10.1007/s11082-017-0907-9 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Photonic Technology Laboratory, Centre for Research in PhotonicsUniversity of OttawaOttawaCanada

Personalised recommendations