S. Wohlfeil, J.-P. Koester, H. Christopher, J. Fricke, P. Della Casa, H. Wenzel, A. Knigge, G. Tränkle

Published in:

Electron. Lett., vol. 61, no. 1, art. e70266, doi:10.1049/ell2.70266 (2025).

Abstract:

We present the integration of an S-bend waveguide into the cavity of a mode-locked diode laser to tune its repetition frequency for use in terahertz time-domain spectroscopy applications. The mode-locked diode laser, featuring a facet-to-facet 6-mm-long straight ridge waveguide, emits light at a wavelength of around 830 nm and operates at a repetition frequency of 6.3 GHz. By incorporating an S-bend into the cavity, the optical path length can be modified, enabling a variation of up to 12 MHz in the repetition frequency. Furthermore, this approach supports the co-integration of two lasers on a single chip, each with a distinct repetition rate but operating under identical environmental and driving conditions, offering a robust and compact two-laser solution for asynchronous optical sampling.

© 2025 Ferdinand-Braun-Institut GmbH. Electronics Letters published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
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