Coherent WDM transmission using quantum-dash mode-locked laser diodes as multi-wavelength source and local oscillator

TL;DR

This paper demonstrates a novel use of quantum-dash mode-locked laser diodes as both multi-wavelength sources and local oscillators for coherent WDM transmission, achieving 4.1 Tbit/s over 75 km.

Contribution

It introduces the first coherent WDM link utilizing QD-MLLDs at both transmitter and receiver, enabling scalable high-speed data transmission.

Findings

Achieved 4.1 Tbit/s data rate over 75 km fiber

Demonstrated dual use of QD-MLLDs as source and local oscillator

First to show coherent WDM with QD-MLLDs at both ends

Abstract

Quantum-dash (QD) mode-locked laser diodes (MLLD) lend themselves as chip-scale frequency comb generators for highly scalable wavelength-division multiplexing (WDM) links in future data-center, campus-area, or metropolitan networks. Driven by a simple DC current, the devices generate flat broadband frequency combs, containing tens of equidistant optical tones with line spacings of tens of GHz. Here we show that QD-MLLDs can not only be used as multi-wavelength light sources at a WDM transmitter, but also as multi-wavelength local oscillators (LO) for parallel coherent reception. In our experiments, we demonstrate transmission of an aggregate data rate of 4.1 Tbit/s (23x45 GBd PDM-QPSK) over 75 km standard single-mode fiber (SSMF). To the best of our knowledge, this represents the first demonstration of a coherent WDM link that relies on QD-MLLD both at the transmitter and the receiver.