Monolithic dual-wavelength high-power DFB laser with sub-100 kHz linewidth for THz application

Area of Science:

• Optics and Photonics
• Terahertz Technology
• Semiconductor Lasers

Background:

• Terahertz (THz) systems require efficient and cost-effective transmitters.
• Existing THz transmitters face challenges in complexity, cost, and power efficiency.
• Monolithic dual-wavelength lasers offer a potential solution for integrated THz sources.

Purpose of the Study:

• To report an optimized monolithic dual-wavelength distributed feedback (DFB) laser for THz applications.
• To address limitations of current THz transmitters, focusing on complexity, cost, and power efficiency.
• To demonstrate stable and high-performance dual-wavelength operation.

Main Methods:

• Design and fabrication of a monolithic dual-wavelength distributed feedback (DFB) laser.
• Characterization of optical power, mode power difference, side-mode suppression ratio (SMSR).
• Analysis of relative intensity noise (RIN) and linewidth under varying temperature and bias conditions.

Main Results:

• Achieved a high optical power of 65.93 mW.
• Maintained a power difference below 1 dB between the two primary modes across a wide temperature range.
• Exceeded 36 dB side-mode suppression ratio (SMSR) for both modes.
• Demonstrated low relative intensity noise peaks (-153.88 dB/Hz and -153.46 dB/Hz).
• Achieved narrow linewidths of 117.33 kHz and 70.59 kHz.

Conclusions:

• The optimized dual-wavelength (DW)-DFB laser provides stable and high-performance operation.
• This laser presents a compact and cost-effective solution for THz transmitter applications.
• The demonstrated performance characteristics are suitable for advancing THz systems.