In an effort to miniaturize a technology that normally requires bulky equipment, scientists have managed to reduce a mode-locked laser (MLL) to the size of an optical chip using an integrated nanophotonics platform. This achievement opens the way to ultrafast laser systems for a variety of applications.
Reducing the size of mode-locked lasers
THE mode-locked lasers (MLL) are capable of generating ultra-short, coherent pulses of light at extremely high speeds on the order of picoseconds and femtoseconds. These devices have enabled the emergence of many technologies in photonics, such as extreme nonlinear optics, two-photon microscopy, and optical computing. However, most MLLs are expensive, power hungry, and require discrete and bulky optical components.
Therefore, the use of ultrafast photonic systems is generally limited to benchtop laboratory experiments. Furthermore, so-called “integrated” MLLs intended to power nanophotonic platforms suffer from critical limitations such as low peak power and lack of controllability.
A new approach to integrated MLLs
By hybridizing a solid-state optical amplifier chip with a novel thin-film lithium niobate nanophotonic circuit, Quishi Guo and his team from the Department of Electrical Engineering at the California Institute of Technology in the United States have created an integrated MLL-sized optical chip.
Accordingly, the MLL generates ultra-short optical pulses of around 4.8 picoseconds at around 1065 nanometers with a peak power of around 0.5 watts – the highest output pulse energy and peak power of all MLLs integrated into nanophotonic platforms.
In addition, the researchers showed that the repetition rate of the integrated MLL can be tuned over a range of about 200 megahertz and that the laser’s coherence properties can be precisely controlled, paving the way to a frequency comb source with fully stabilized on-chip nanophotonics.
synthetic
The Caltech researchers’ achievement marks an important step in the miniaturization of photonic technologies. Your work on the mode-locked laser could pave the way for more accessible and manageable ultrafast nanophotonic systems for a wide range of applications.
For better understanding
What is a mode-locked laser (MLL)?
A mode-locked laser is a type of laser that produces ultra-short, coherent light pulses at extremely high speeds in the picosecond and femtosecond range.
What are the challenges associated with traditional MLLs?
Traditional MLLs are often expensive, power hungry, and require discrete and bulky optical components. In addition, they have limitations such as low peak power and lack of controllability.
They used a hybrid integration of a solid-state optical amplifier chip with a novel thin-film lithium niobate nanophotonic circuit to create an integrated MLL the size of an optical chip.
What performance does this new integrated MLL offer?
The integrated MLL generates ultra-short optical pulses of approximately 4.8 picoseconds at approximately 1065 nanometers with a peak power of approximately 0.5 watts. In addition, the repetition rate can be adjusted to a range of around 200 megahertz.
What implications does this finding have?
This achievement could pave the way for more accessible and manageable ultrafast nanophotonic systems for a wide range of applications.
Main lessons
| to teach |
|---|
| 1. Mode-locked lasers (MLL) produce ultra-short pulses of light at extremely high speeds. |
| 2. Traditional MLLs are expensive, power hungry, and require bulky optical components. |
| 3. Guo and his team developed an integrated MLL the size of an optical chip. |
| 4. The integrated MLL generates ultra-short optical pulses of about 4.8 picoseconds at about 1065 nanometers. |
| 5. The built-in MLL has a peak power of approximately 0.5 watts. |
| 6. The repetition rate of the built-in MLL can be set to a range of approximately 200 megahertz. |
| 7. This achievement could pave the way for more accessible and manageable ultrafast nanophotonic systems. |
| 8. Challenges remain in further optimizing these systems. |
| 9. The coherence characteristics of the laser can be precisely controlled. |
| 10. This provides the path to a fully stabilized on-chip nanophotonic frequency comb source. |
References
Guo, Q. et al. (2023). Hybrid integration of an optical semiconductor amplifier chip with a novel nanophotonic thin-film lithium niobate circuit. Journal of Nanophotonics.
Article: “Ultrafast mode-locked laser in nanophotonic lithium niobate” – DOI: 10.1126/science.adj5438
[ Rédaction ]