Sagnac loop mirror and micro-ring based laser cavity for silicon-on-insulator.

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Lasers

Background:

• Integrated lasers are crucial for silicon photonic integrated circuits.
• On-chip cavity design significantly impacts laser performance and yield.
• Existing designs often rely on distributed Bragg gratings requiring ultra-fine feature sizes.

Purpose of the Study:

• To propose and demonstrate a novel silicon-based laser cavity design.
• To utilize a Sagnac loop mirror and a micro-ring wavelength filter for laser fabrication.
• To achieve precise wavelength control and high performance in silicon lasers.

Main Methods:

• Fabrication of a silicon laser cavity incorporating a Sagnac loop mirror and a micro-ring filter.
• Utilizing a 248 nm stepper for lithographic control of laser wavelength.
• Characterization of the laser's performance, including side-mode suppression ratio (SMSR), linewidth, and output power.

Main Results:

• Demonstration of a proof-of-concept silicon laser operating at 1551.7 nm.
• Achieved a side-mode suppression ratio (SMSR) of 44 dB.
• Measured a linewidth of 1.2 MHz and an on-chip output power of 4.8 mW.
• Demonstrated lithographic wavelength control with a standard deviation of 3.6 nm.

Conclusions:

• The proposed Sagnac loop mirror and micro-ring filter combination offers a viable and simpler alternative for silicon laser cavity design.
• This method enables precise, lithographically controlled laser wavelengths.
• The demonstrated device shows promising performance metrics for silicon photonic integrated circuits.