Quantum dot mode-locked frequency comb with ultra-stable 25.5 GHz spacing between 20°C and 120°C
Using a quantum dot (QD) mode-locked laser as a comb source is an attractive solution for not only DWDM networks, but also spectroscopy, sensing, and many other emerging applications due to its compactness, low power consumption and enhanced performances. Quantum dot lasers have been widely studied as the three-dimensional carrier confinement structure and demonstrated leads to lower threshold current density, lower sensitivity to temperature, and broad spectral gain bandwidth. In their work, Pan and coworkers developed an uncooled 25 GHz spacing comb source based on a QD laser structure showing low RIN value and good frequency stability over a large operating range of temperature (20°C to 100°C) by tuning the laser gain current. This first demonstration represents a step toward efficient and low cost light sources for the next generation optical communications.