Over 300 mW O-band 8-channel DFB laser array for optical I/O technology

Area of Science:

• Photonics
• Semiconductor Lasers
• Optical Communications

Background:

• Optical input/output (I/O) applications require high-power, stable laser sources.
• Existing laser technologies face limitations in power, efficiency, and single-mode operation for demanding I/O tasks.

Purpose of the Study:

• To demonstrate a high-power distributed feedback (DFB) laser array optimized for optical I/O.
• To improve single-transverse-mode characteristics and reduce internal loss in DFB lasers.
• To achieve stable single-longitudinal-mode operation with high power output per channel.

Main Methods:

• Fabrication of a DFB laser array incorporating a high-refractive-index layer in the N-doped region.
• Implementation of an asymmetric π-phase-shift using the reconstruction-equivalent chirp technique.
• Characterization of output power, single-mode yield, spectral properties, and noise performance.

Main Results:

• Achieved single-mode operation at a 5 µm ridge width with low internal loss (3 cm⁻¹).
• Demonstrated output powers exceeding 300 mW per channel at 25 °C and 800 mA injection current.
• Exhibited stable single-longitudinal-mode operation with side mode suppression ratios > 50 dB and low relative intensity noise (-154 dB/Hz).

Conclusions:

• The developed DFB laser array is suitable for high-power optical I/O applications.
• The epitaxial design and phase-shift technique enable high single-mode yield and stable operation.
• The laser array shows strong potential for enabling high-speed optical interconnects.