Monolithically-integrated distributed feedback laser compatible with CMOS processing.

Area of Science:

• Photonics
• Materials Science
• Integrated Optics

Background:

• Monolithic integration of lasers and active devices is crucial for advanced silicon microphotonic systems.
• Previous methods for fabricating laser gain media require high temperatures, limiting CMOS compatibility.
• Developing low-temperature deposition processes for high-performance gain media is essential for scalable photonic integration.

Purpose of the Study:

• To demonstrate an optically-pumped, integrated distributed feedback laser using a CMOS-compatible process.
• To develop a low-temperature deposition method for a rare-earth-doped aluminum oxide gain medium.
• To enable monolithic integration of lasers with modulators and detectors in silicon photonics.

Main Methods:

• Fabrication of a distributed feedback laser using a CMOS-compatible process.
• Deposition of a rare-earth-doped aluminum oxide gain medium via substrate-bias-assisted reactive sputtering at 250 °C.
• Characterization of laser performance, including pump threshold and slope efficiency.

Main Results:

• Demonstrated an optically-pumped, integrated distributed feedback laser with a pump threshold of 24.9 mW and a slope efficiency of 1.3 % at 1552.98 nm.
• Achieved optical quality films with 0.1 dB/cm background loss at a low deposition temperature of 250 °C.
• Laser performance comparable to devices fabricated at much higher temperatures (> 550 °C).

Conclusions:

• The developed low-temperature deposition process is fully compatible with back-end-of-line CMOS fabrication.
• This work represents a significant advancement towards the monolithic integration of amplifiers and lasers in silicon microphotonic systems.
• The integrated laser technology holds promise for next-generation optical communication and computing.