Tiny yet Powerful: How Lasers on Chips Change the Game Rules of Photonics

Chip level ultrafast mode-locked laser based on nanophotonic lithium niobate.
Researchers have created a compact mode-locked laser integrated into a nanophotonic platform, capable of generating high-power and ultrafast optical pulses. The breakthrough in miniaturization of MLL technology can significantly expand the application of photonics.

Innovation in mode-locked laser technology
To improve the technology that typically requires bulky desktop devices, Quishi Guo and his colleagues reduced the size of mode-locked lasers to optical chips with integrated nanophoton platforms. The research results show that it provides prospects for the development of ultrafast nanophotonic systems for widespread applications.

The potential of miniaturizing MLL
A mode-locked laser can generate coherent ultra short optical pulses at an extremely fast speed - approximately picoseconds and femtoseconds. These devices have achieved many technologies in the field of photonics, including extreme nonlinear optics, two-photon microscopy, and optical computing.

However, most MLLs are expensive, require high power consumption, and require bulky discrete optical components and equipment. Therefore, the use of ultrafast photon systems is usually limited to desktop laboratory experiments. More importantly, the so-called "integrated" MLL used to drive nanophotonic platforms has key limitations, such as low peak power and lack of controllability.

Breakthrough in Nanophoton MLL Integration
Guo et al. created an optical chip sized integrated MLL by mixing semiconductor optical amplifier chips with a novel thin film lithium niobate nanophotonic circuit.

According to the author, MLL generates ultra short to 4.8 picosecond light pulses at approximately 1065 nanometers, with a peak power of~0.5 watts - the highest output pulse energy and peak power of any integrated MLL in the nanophotonic platform.

In addition, researchers have shown that the repetition rate of integrated MLL can be tuned in the range of~200 MHz and the coherent characteristics of the laser can be precisely controlled, providing a pathway for a completely stable on-chip nanophoton frequency comb source.

Source: Laser Net