Passive harmonically mode-locked laser on lithium niobate nanophotonic circuits
Y. Wang1,2,†, G. Han1,2,†, J.-P. Koester3, H. Wenzel3, W. Wang1,2, W. Deng1,2, Z. Feng1,2, M. Tian1,2, A. Alù1,2, A. Knigge3, and Q. Guo1,2
Published in:
Optica, vol. 13, no. 7, pp. 1223-1231, doi:10.1364/OPTICA.584937 (2026).
Abstract:
Mode-locked lasers (MLLs) are essential for a wide range of photonic applications, such as frequency metrology, biological imaging, and high-bandwidth coherent communications. The growing demand for compact and scalable photonic systems is driving the development of MLLs on various integrated photonics material platforms. Along these lines, developing MLLs on the emerging thin-film lithium niobate (TFLN) platform holds the promise to greatly broaden the application space of MLLs by harnessing TFLN’s unique electro-optic (E-O) response and quadratic optical nonlinearity. Here, we demonstrate an electrically pumped, self-starting passively MLL in lithium niobate integrated photonics based on its hybrid integration with a GaAs quantum-well gain medium and saturable absorber. Our demonstrated MLL generates 4.69 ps optical pulses centered around 1060 nm with on-chip peak power exceeding 43 mW. The pulse duration can be further compressed to 1.91 ps via linear dispersion compensation. Remarkably, passive mode locking occurs exclusively at the second harmonic of the cavity free spectral range, exhibiting a high pulse repetition rate ∼20 GHz. We elucidate the temporal dynamics underlying this self-starting passive harmonic mode-locking behavior using a traveling-wave model. Our work offers insights into the realization of compact, high-repetition-rate MLLs in the TFLN platform, with promising applications for monolithic ultra-fast microwave waveform sampling and analog-to-digital conversion.
1 Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA
2 Physics Program, Graduate Center, City University of New York, 3655th Ave, New York, New York 10016, USA
3 Ferdinand-Braun-Institut (FBH), Gustav-Kirchhoff-Str. 4, 12489Berlin, Germany
† These authors contributed equally to this work
Related Topics:
Effective refractive index, Integrated photonics, Lithium niobate, Saturable absorbers, Scanning electron microscopy, Tunable lasers
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