Design the Impact of Temperature on the Modulation Bandwidth of InGaAs Vertical Cavity Surface Emitting Lasers (VCSELs) for Efficient Optical Interconnect

Document Type : Research Paper

Authors

1 Department of Physics, Faculty of Science and Health, Koya University, Kurdistan Region - Iraq

2 Department of Physics, Faculty of Science and Health, Koya University, Koya, Kurdistan Region - Iraq

Abstract

This simulation work, based on the design of an 850 nm InGaAs/AlGaAs quantum well (QWs) vertical cavity surface emitting laser (VCSEL), presents significant challenges, particularly due to the limitations of device bandwidth at higher temperatures. We propose a comprehensive modelling approach to optimize the dynamic performance of a VCSEL structure with an oxide aperture diameter of 6 µm, specifically to achieve higher bandwidth at lower bias currents. The MATLAB simulation evaluates the variation of critical parameters, such as threshold current, differential efficiency, output power, and small-signal modulation, across a wide operating temperature range. Our findings indicate that in static analysis, the threshold current exhibits a positive temperature dependence, increasing with rising temperature, while both differential efficiency and optical output power decrease. Dynamic analysis reveals that although the 3-dB modulation bandwidth reduces with temperature, the VCSEL maintains high-speed performance exceeding 36 GHz at 20 °C and 24 GHz at 120 °C under a bias current of 14 mA. The temperature dependence of the modulation current efficiency factor (MCEF) provides insight into optimizing VCSEL structures for reliable high-speed operation over broad thermal conditions.

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Kirkuk Journal of Science
Volume 20, Issue 3
September 2025
Page 31-40

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History

  • Receive Date: 15 June 2025
  • Revise Date: 25 July 2025
  • Accept Date: 26 July 2025

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