Hybrid distributed Bragg reflector laser on Si with a transfer printed InAs/GaAs quantum dot amplifier

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Quantum dots (QDs) offer unique optical properties for laser gain media.
• Integrated photonics requires efficient methods for combining dissimilar materials.
• Silicon photonics provides a robust platform for optical circuits.

Purpose of the Study:

• To demonstrate a hybrid integrated laser using transfer printing.
• To integrate an Indium Arsenide/Gallium Arsenide (InAs/GaAs) quantum dot (QD) amplifier onto a silicon waveguide.
• To characterize the laser performance of the hybrid device.

Main Methods:

• Transfer printing of a 1.6 mm long QD waveguide amplifier.
• Fabrication of the QD amplifier as an airbridge using a spin-on-glass sacrificial layer.
• Integration onto a silicon-on-insulator (SOI) waveguide via pick-and-place assembly with an elastomer stamp.
• Characterization of laser oscillation wavelength, threshold current, and operating temperature range.

Main Results:

• Successful hybrid integration of a QD amplifier on a Si waveguide with distributed Bragg reflectors (DBRs).
• Observed laser oscillation around 1250 nm wavelength.
• Achieved a threshold current of 47 mA at room temperature.
• Demonstrated stable laser operation up to 80°C.

Conclusions:

• Transfer printing enables the integration of long QD amplifiers for hybrid laser development.
• This approach leverages the superior gain properties of QDs in integrated photonic circuits.
• The demonstrated hybrid laser is a significant step towards advanced optoelectronic devices.