High-power thulium lasers on a silicon photonics platform

Area of Science:

• Photonics and optical engineering
• Materials science
• Integrated optics

Background:

• Mid-infrared (MIR) lasers are crucial for applications like spectroscopy, sensing, and communication.
• Silicon photonics offers a low-cost, compact platform for integrated optical devices.
• High-power, efficient monolithic light sources in the 2 μm range remain underdeveloped.

Purpose of the Study:

• To develop high-power, high-efficiency, monolithic silicon-based laser sources operating in the 2 μm wavelength region.
• To demonstrate the feasibility of CMOS-compatible thulium-doped lasers on a silicon photonic platform.
• To extend the capabilities of silicon photonics for MIR applications.

Main Methods:

• Fabrication of thulium-doped distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers.
• Integration of these lasers onto a silicon photonic platform.
• Characterization of laser performance, including output power, slope efficiency, and side-mode suppression ratio (SMSR).

Main Results:

• Achieved single-mode output powers of up to 267 mW (DFB) and 387 mW (DBR).
• Demonstrated high slope efficiencies of 14% (DFB) and 23% (DBR).
• Obtained side-mode suppression ratios exceeding 70 dB for both laser types.

Conclusions:

• Successfully developed high-performance, CMOS-compatible thulium-doped silicon photonic lasers in the 2 μm region.
• These results represent a significant advancement for monolithic MIR light sources on silicon.
• The work broadens the application scope of silicon photonic microsystems in the mid-infrared spectrum.