Stepped-height ridge waveguide MQW polarization mode converter monolithically integrated with sidewall grating DFB...

Area of Science:

• Photonics and Optoelectronics
• Semiconductor Lasers
• Integrated Optics

Background:

• Polarization mode converters are crucial for optical communication systems.
• Monolithic integration of lasers and converters simplifies device architecture.
• Distributed-feedback (DFB) lasers offer stable single longitudinal mode operation.

Purpose of the Study:

• To demonstrate a novel monolithically integrated polarization mode converter and DFB laser at 1555 nm.
• To achieve efficient TE-to-TM polarization conversion with SLM operation.
• To reduce fabrication complexity and cost through an identical epitaxial layer scheme.

Main Methods:

• Fabrication of a stepped-height ridge waveguide polarization mode converter integrated with a sidewall grating DFB laser.
• Utilizing a single metalorganic vapor-phase epitaxy step and two III-V material dry etching steps.
• Characterization of device performance across a range of DFB injection currents (IDFB).

Main Results:

• Stable single longitudinal mode (SLM) operation achieved.
• Efficient polarization conversion from TE to TM mode with >94% efficiency.
• High TM mode purity of 98.2% obtained at IDFB = 180 mA.
• Wide operating current range (140 mA to 190 mA) for efficient conversion.

Conclusions:

• The integrated device demonstrates high performance for polarization control and laser emission.
• The simplified fabrication process significantly reduces manufacturing complexity and cost.
• This approach offers a promising solution for advanced photonic integrated circuits.