Tunable coupled-cavity semiconductor laser based on a half-wave bow-tie coupler.

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Integrated Photonics

Background:

• Tunable lasers are crucial for optical communication and spectroscopy.
• Existing tunable laser designs often require complex fabrication processes.
• Achieving high mode selectivity and wide tuning range simultaneously remains a challenge.

Purpose of the Study:

• To propose and demonstrate a novel tunable coupled-cavity semiconductor laser.
• To utilize a half-wave bow-tie coupler for enhanced performance.
• To achieve wide wavelength tuning with high mode selectivity and side-mode suppression.

Main Methods:

• Design and fabrication of a coupled-cavity laser incorporating a half-wave bow-tie coupler.
• Experimental demonstration of wavelength tuning by adjusting a single electrode.
• Characterization of tuning range, channel spacing, and side-mode suppression ratio.

Main Results:

• Successfully demonstrated a widely tunable semiconductor laser.
• Achieved 29.6 nm wavelength tuning, covering 38 channels with 100 GHz spacing.
• Obtained a side-mode suppression ratio exceeding 35 dB.
• The novel coupler requires no complex gratings or multiple epitaxial growths.

Conclusions:

• The proposed half-wave bow-tie coupler enables efficient and selective wavelength tuning in semiconductor lasers.
• This design offers a simpler fabrication process compared to traditional methods.
• The demonstrated laser performance is suitable for various optical communication applications.