Experimental demonstration of DFB lasers with active distributed reflector

Area of Science:

• Photonics and Optical Engineering
• Semiconductor Lasers
• Optical Communications

Background:

• Distributed Feedback (DFB) lasers are crucial for optical communication.
• Existing DFB laser designs face limitations in performance and integration.
• Novel reflector designs are needed to enhance laser efficiency and bandwidth.

Purpose of the Study:

• To experimentally demonstrate a new DFB laser architecture.
• To integrate an active distributed reflector within the DFB laser structure.
• To evaluate the performance of the novel DFB laser for high-speed optical transmission.

Main Methods:

• Fabrication of DFB lasers with an active distributed reflector sharing the same waveguide core.
• Optical pumping of the distributed reflector by the laser itself to near transparency.
• Characterization of laser performance including threshold current, slope efficiency, side mode suppression ratio, and modulation bandwidth.
• Testing of 28-Gb/s data transmission over 10-km single-mode fiber.

Main Results:

• Achieved a low threshold current of 10 mA.
• Obtained a slope efficiency of 0.38 mW/mA.
• Demonstrated a side mode suppression ratio exceeding 55 dB.
• Reached a modulation bandwidth of 24 GHz at 60 mA current injection.
• Successfully transmitted data at 28 Gb/s over 10 km with a power penalty < 0.5 dB.

Conclusions:

• The novel DFB laser with an active distributed reflector offers high performance.
• The integrated design simplifies fabrication while enhancing optical feedback.
• The demonstrated capabilities are promising for next-generation optical communication systems.