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Dual optical frequency comb downconversion of D-band mm-wave signals

Callum Deakin, Zichuan Zhou, Ronit Sohanpal, Zhixin Liu

TL;DR

This paper tackles the challenge of receiving D-band mm-wave signals (110–170 GHz) without relying on high-frequency RF components or tightly stabilized lasers. It introduces a dual optical frequency comb scheme with repetition rates $f_{ ext{sig}}$ and $f_{ ext{ref}} = f_{ ext{sig}} + \Delta f$, enabling downconversion to baseband through beat notes between signal and reference comb lines, with the mapping governed by $ n_{ ext{sig}}$ and $ n_{ ext{ref}}$ relations. Using a >200-GHz-bandwidth TFLN Mach-Zehnder modulator and low-bandwidth photodetection, the system achieves baseband reception with SNRs around $25$ dB across the D-band and NGMI $> 0.98$, without frequency tuning or optical filters. The results demonstrate a tunable, filter-free photonic receiver suitable for ISAC and mm-wave backhaul, while highlighting practical enhancements needed in modulator efficiency, integration, and carrier identification strategies.

Abstract

We demonstrate a dual optical frequency comb concept that down-converts arbitrary narrowband D-band (110-170 GHz) signals to baseband without any filter or optical/RF frequency tuning, using low frequency RF components.

Dual optical frequency comb downconversion of D-band mm-wave signals

TL;DR

This paper tackles the challenge of receiving D-band mm-wave signals (110–170 GHz) without relying on high-frequency RF components or tightly stabilized lasers. It introduces a dual optical frequency comb scheme with repetition rates and , enabling downconversion to baseband through beat notes between signal and reference comb lines, with the mapping governed by and relations. Using a >200-GHz-bandwidth TFLN Mach-Zehnder modulator and low-bandwidth photodetection, the system achieves baseband reception with SNRs around dB across the D-band and NGMI , without frequency tuning or optical filters. The results demonstrate a tunable, filter-free photonic receiver suitable for ISAC and mm-wave backhaul, while highlighting practical enhancements needed in modulator efficiency, integration, and carrier identification strategies.

Abstract

We demonstrate a dual optical frequency comb concept that down-converts arbitrary narrowband D-band (110-170 GHz) signals to baseband without any filter or optical/RF frequency tuning, using low frequency RF components.
Paper Structure (5 sections, 1 equation, 3 figures)

This paper contains 5 sections, 1 equation, 3 figures.

Table of Contents

  1. Introduction
  2. Dual optical frequency comb D-band receiver concept
  3. Experimental setup
  4. Results and discussion
  5. Conclusion

Figures (3)

  • Figure 1: (a) Dual comb concept. (b) Comb line mapping for detected D-band frequencies 110-170 GHz with $f_{\textnormal{sig}} = 25$ GHz and $f_{\textnormal{ref}} = 27$ GHz. Sig USB and Sig LSB refer to the upper and lower sidebands generated by the MZM respectively.
  • Figure 2: (a) Experimental setup. PM, phase modulator; MZM, Mach-Zehnder modulator; EDFA, erbium doped fiber amplifer; TIA, transimpedance amplifier. (b) Optical spectra for signal comb $f_{\textnormal{sig}} = 25$ GHz, and reference comb $f_{\textnormal{ref}} = 27$ GHz.
  • Figure 3: (a) Optical spectrum excerpt showing a modulated signal comb example (155.82 GHz) and reference comb. Only for $n_\textnormal{ref}= 3$, $n_\textnormal{sig}= -3$ do the combs generate a beat signal on the photodiode. (b) Recovered SNR across D-band frequencies 110-170GHz. (c) Example recovered spectrum for $f_\textnormal{in}=132.252$ GHz and its (d) corresponding constellation.