"This study demonstrates a novel and unique design and working principle for ultrafast mode-locked lasers. The realization of electrically pumped ultrafast lasers on thin-film lithium niobate chips will significantly expand the potential of this field and has very important implications for photonics and other fields."
The study, which was highly praised by the reviewers, comes from the City University of New York and California Institute of Technology teams. They demonstrated the world's first electrically pumped mode-locked laser with high peak pulse power integrated on a thin-film lithium niobate optical chip.
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Photo 丨Science current issue cover
In this study, the researchers cleverly fused the high laser gain of a triple-five semiconductor with the excellent electro-optical properties of thin-film lithium niobate to create an on-chip mode-locked laser through hybrid integration, realizing a high-power ultrashort-pulse laser output.
Notably, the laser produced ultrashort optical pulses with a repetition frequency of 10 GHz and a width of 4.8 picoseconds at around 1065 nm, with a pulse energy of more than 5 picojoules and a peak power of more than 0.5 watts. "Up to now, our laser output pulse energy and peak power are the highest for mode-locked lasers under the nanophotonics platform." Qiusi Guo said.
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Photo丨Qiu-Shi Guo
With its high output peak power and precise frequency control capability, the mode-locked laser is expected to build an ultrafast nonlinear optical system with full on-chip integration, which will lead to the realization of fully frequency-locked optical frequency combs, supercontinuum spectral light sources and atomic clocks. This will greatly boost the development of optical communications, medical imaging, precision measurement, computing and other fields. "In the longer term, the on-chip mode-locked laser may have irreplaceable applications in the fields of coherent communications, precision timing, and precision measurement." Guo Qiushi said.
