Ultra-low-threshold Er:Yb sol-gel microlaser on silicon

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Semiconductor Lasers

Background:

• Ultra-low threshold lasers are essential for telecommunications, satellite communications, biochemical detection, and optical computing.
• Integrating lasers with CMOS technology requires optimizing gain media and pumping methods for sub-milliWatt thresholds.
• Rare-earth ion co-doping enhances laser efficiency by utilizing secondary dopants to boost primary dopant lasing.

Purpose of the Study:

• To demonstrate a lithographically fabricated, Erbium:Ytterbium co-doped microcavity laser on a silicon substrate.
• To investigate the impact of varying Erbium and Ytterbium doping concentrations on laser performance.
• To achieve ultra-low lasing thresholds for practical applications.

Main Methods:

• Fabrication of a microcavity laser using lithography on a silicon substrate.
• Co-doping the gain medium with Erbium and Ytterbium ions.
• Experimental determination of quality factor and pump threshold for various doping concentrations.

Main Results:

• Successful fabrication of a CMOS-compatible microcavity laser.
• Experimental verification of the inter-dependent relationship between Erbium and Ytterbium doping concentrations.
• Achieved an optimized lasing threshold as low as 4.2 microwatts.

Conclusions:

• The co-doping strategy effectively enhances laser efficiency and reduces threshold power.
• The developed microcavity laser demonstrates potential for integration into advanced photonic circuits.
• Ultra-low threshold lasers are feasible with optimized rare-earth ion doping and microcavity design.