Integrated Wavelength-Tuned Optical mm-Wave Beamformer with Doubled Delay Resolution

Xuebing Zhang, Mingyang Zhao, Yuqing Jiao, Zizheng Cao (Corresponding author), A.M.J. Koonen

Research output: Contribution to journalArticleAcademicpeer-review

14 Citations (Scopus)
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Integrated optical true time delay lines attract lots of attention for optically controlled mm-wave beam steering due to its low-loss/broadband performance and stable/compact system architecture. However, for remotely-controlled networks, the techniques that require local-site actively-tuned elements would make the network control more complicated. A passive design using wavelength-tuning is regarded as a promising candidate. In this paper, an integrated wavelength-tuned optical mm-wave beamformer with doubled delay resolution is proposed and demonstrated in a generic InP platform. A bidirectional looped-back arrayed waveguide grating (AWG) module acts as the stepwise tunable delay unit. By introducing an extra AWG router for delay mode (positive/negative) selection and a bidirectional optical interface, a pure λ-tuned, resolution-doubled optical delay network is realized without using any active component (e.g. heaters, current injection) at the local site. This photonic passive design is more beneficial to the remotely-controlled mm-wave beam steering system. Furthermore, the AWG router potentially allows multi-port wavelength switching to support the scaling-up of the network. The fabrication-caused delay error of <1.1 ps is experimentally verified on-chip. A further proof-of-concept 38-GHz fiber-wireless beam steering system with a 186° angular steering is experimentally demonstrated using QAM-4 modulation. Accurate mm-wave phase shifts originated from the proposed optical beamformer are obtained, which proves the effectiveness of the tunable integrated beamformer.

Original languageEnglish
Article number8985297
Pages (from-to)2353-2359
Number of pages7
JournalJournal of Lightwave Technology
Issue number8
Publication statusPublished - 15 Apr 2020


  • Indoor fiber-wireless communications
  • integrated photonics
  • looped-back AWG
  • optical mm-wave beamformer
  • wavelength-tuned


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