Researchers Discover Sensitivity of Semiconductor Lasers to Optical Feedback

Researchers at the Universitat Politecnica de Catalunya have conducted a study on the effect of optical feedback on the spatial coherence of diode lasers. Their findings indicate that semiconductor lasers are highly sensitive to optical feedback, which can be used to reduce speckles in laser-based illumination systems. The study employed the speckle technique to analyze the impact of optical feedback on the spatial coherence of diode lasers. The research may have significant implications for the development of laser-based technology.

Key Takeaways:

• The study discovered that semiconductor lasers are sensitive to optical feedback, which can be used to reduce speckles in laser-based illumination systems.
• The speckle technique was used to analyze the effect of optical feedback on the spatial coherence of diode lasers.
• The researchers observed that, during the laser turn-on, without feedback, the speckle contrast increases gradually, but with strong feedback, the speckle contrast increases sharply.
• High-contrast regions alternate with low-contrast regions under certain current modulation.
• The research may have applications in laser-based illumination systems.

Statistics:

• The speckle contrast increases sharply with strong feedback.
• The speckle contrast increases gradually without feedback.

Sources:

• Invited - Experimental characterization of optical feedback and current modulation effects on the spatial coherence of a semiconductor laser. EPJ Web of Conferences, 2025,335():06001. (EPJ Web of Conferences - http://www.epj-conferences.org/).
• NewsRx. Data on Physics Described by Researchers at Universitat Politecnica de Catalunya (Invited - Experimental characterization of optical feedback and current modulation effects on the spatial coherence of a semiconductor laser). Physics Week. October 21, 2025; p 44.