A continuously tunable and filterless optical millimeter-wave generation via frequency octupling

TLDR

The study proposes a cost‑effective, continuously tunable, filter‑less optical millimeter‑wave generator using frequency octupling. It employs frequency octupling without optical filtering, enabling straightforward integration into wavelength‑division‑multiplexing systems. The prototype delivers 60‑GHz and 80‑GHz optical MMW signals with 30‑dB sideband suppression, 50% duty‑cycle waveforms, –73 dBc/Hz phase noise at 10 kHz, and can scale to 320 GHz using a 40‑GHz external modulator.

Abstract

This work proposes a cost-effective, continuously tunable and filterless optical millimeter-wave (MMW) signal generation employing frequency octupling. Optical MMW signals with 30-dB undesired sideband suppression ratios can be obtained. Since no optical filtering is required, the proposed system can be readily implemented in wavelength-division-multiplexing (WDM) systems. V-band 60-GHz and W-band 80-GHz optical MMW signals are experimentally demonstrated. Because of the high undesired sideband suppression ratio, 60-GHz waveform with 50% duty cycle is observed. The single-sideband (SSB) phase noise of the generated 60-GHz signal is -73 dBc/Hz at 10 kHz. The proposed system is a viable solution for the future ultra-high frequency MMW applications up to 320 GHz using the external modulator with a limited bandwidth of 40 GHz.