Photonic crystal laser with mode selective mirrors.

Area of Science:

• Photonics
• Semiconductor Lasers
• Nanophotonics

Background:

• Quantum-dot lasers are crucial for advanced optical applications.
• Photonic crystal waveguides offer unique light confinement properties.
• Mini-stopbands (MSB) in W3 waveguides present potential as integrated optical components.

Purpose of the Study:

• To investigate the use of a mini-stopband (MSB) as a mirror in a GaAs-based quantum-dot laser.
• To demonstrate single-mode, continuous-wave lasing using an MSB mirror.
• To evaluate the mode selectivity and potential for threshold reduction.

Main Methods:

• Fabrication of a GaAs-based quantum-dot laser incorporating a W3 line-defect photonic crystal waveguide.
• Utilizing the mini-stopband (MSB) of the waveguide as a reflective element.
• Experimental characterization of lasing performance, including mode selectivity and threshold current.
• Finite-difference time-domain (FDTD) simulations to analyze mirror reflectivity and interface optimization.

Main Results:

• Single-mode, continuous-wave lasing was achieved in broad area lasers.
• Lasing was sustained up to 125 mA, demonstrating high mode selectivity of the MSB mirror (2.7x laser threshold).
• FDTD calculations predicted a potential fourfold increase in reflectivity with interface optimization.

Conclusions:

• The mini-stopband (MSB) of a W3 photonic crystal waveguide functions effectively as a mirror for quantum-dot lasers.
• The demonstrated mode selectivity is high, enabling stable single-mode operation.
• Further optimization of the MSB mirror interface holds significant promise for reducing laser thresholds and improving performance.