Athermalization of the Lasing Wavelength in Vertical-Cavity Surface-Emitting Lasers
L. Persson1, F. Hjort1, G. Cardinali2, J. Enslin2, T. Kolbe3, T. Wernicke2, M. Kneissl2,3, J. Ciers1, and Å. Haglund1
Published in:
Laser Photonics Rev., vol. 17, no. 8, pp. 2300009, doi:10.1002/lpor.202300009 (2023).
Abstract:
A concept for vertical-cavity surface-emitting lasers (VCSELs) is proposed and demonstrated to obtain a lasing wavelength with unprecedented temperature stability. The concept is based on incorporating a dielectric material with a negative thermo-optic coefficient, dn/dT, in the distributed Bragg reflectors (DBRs) to compensate the positive dn/dT of the semiconductor cavity. In a short cavity, the optical field has a significant overlap with the DBRs, and the redshift of the lasing wavelength caused by the semiconductor cavity can be compensated by the negative dn/dT of the DBRs. Here, proof of this concept is presented for optically-pumped VCSELs emitting at 310 nm, demonstrating a lasing wavelength that even blueshifts by less than 0.1 nm over an 80 °C range with a maximum slope of –3.4 pm K−1. This is to be compared with a redshift of 1–1.5 nm over the same temperature range reported for III-nitride blue-emitting VCSELs. Furthermore, this method can also be implemented in VCSELs with longer cavity lengths by including a dielectric layer between the semiconductor and the DBR. The approach used here to obtain a temperature-stable lasing wavelength is generic and can therefore be applied to VCSELs in all material systems and lasing wavelengths.
1 Department of Microtechnology and Nanoscience Chalmers University of Technology, Gothenburg 41296, Sweden
2 Institute of Solid State Physics Technische Universität Berlin, 10623 Berlin, Germany
3 Ferdinand-Braun-Institut, 12489 Berlin, Germany
Keywords:
AlGaN, dielectric DBR, electrochemical etching, ultraviolet, UVB, vertical-cavity surface-emitting lasers, wavelength stability
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