Enhanced high brightness DBR tapered diode laser based on polarization match

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Materials Science

Background:

• Tapered diode lasers suffer from polarization mismatch between ridge and tapered sections, degrading beam quality.
• Transverse Magnetic (TM) high-order modes generated in the ridge section are amplified in the tapered section, reducing output brightness.
• This polarization mismatch limits the performance of high-power tapered diode lasers.

Purpose of the Study:

• To mitigate polarization mismatch in tapered diode lasers.
• To enhance the fundamental mode seed source and improve the degree of polarization (DOP).
• To achieve high output power and brightness with superior beam quality.

Main Methods:

• Employing deep etching in the ridge waveguide section.
• Introducing compressive stress in the gain-guided tapered amplifier section.
• Fabricating a tapered diode laser integrating these modifications.

Main Results:

• Achieved a fundamental mode seed source with high TE degree of polarization (DOP).
• Improved polarization matching between the ridge and tapered sections.
• Demonstrated a tapered diode laser with M 2 (1/e 2 )=1.2 beam quality at 11.57 W output power.
• Attained a peak electro-optical efficiency of 59.8% and maximum output brightness of 936 MW·cm -2 ·sr -1 .

Conclusions:

• The combined deep etching and compressive stress method effectively suppresses TM modes and improves polarization matching.
• This approach significantly enhances beam quality and output brightness in tapered diode lasers.
• The fabricated device represents a significant advancement for high-power semiconductor laser applications.