Resonator-enhanced distributed Bragg reflector lasers.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Laser Physics

Background:

• Narrow-linewidth lasers are crucial for optical communications, metrology, and microwave photonics.
• Integrated laser platforms face trade-offs between linewidth, tunability, and robustness.
• Existing solutions often sacrifice performance in one area to achieve gains in others.

Purpose of the Study:

• To introduce and demonstrate a novel class of integrated lasers overcoming traditional limitations.
• To achieve ultra-narrow linewidths, wide mode-hop-free tunability, and turnkey operation simultaneously.
• To provide a cost-effective, high-performance alternative to bulky benchtop lasers.

Main Methods:

• Development of a resonator-enhanced distributed Bragg reflector (RE-DBR) laser architecture.
• Incorporation of a grating-assisted ring resonator as a compact external cavity for feedback.
• Experimental demonstration of the RE-DBR laser's performance characteristics.

Main Results:

• Demonstrated a RE-DBR laser with a 24 Hz Lorentzian linewidth.
• Achieved a 34 GHz mode-hop-free tuning range.
• Confirmed universal turnkey operability with a sub-4 mm² footprint.

Conclusions:

• RE-DBR lasers circumvent the linewidth-tunability trade-off inherent in conventional DBR lasers.
• These lasers maintain high optical coherence and stable operation across a broad tuning range.
• RE-DBR lasers represent a significant advancement for integrated, high-coherence optical sources.