Self-mode-locking in a high-power hybrid silicon nitride integrated laser

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Microwave Photonics

Background:

• Mode-locked lasers are crucial for microwave photonic applications, often serving as local oscillators.
• Hybrid integrated lasers offer advantages for integration with passive processing circuits.

Purpose of the Study:

• To report on the self-mode-locking of a novel hybrid integrated laser.
• To investigate the characteristics of the laser's output spectrum.

Main Methods:

• Fabrication of a hybrid integrated laser with two indium phosphide (InP) gain sections.
• Incorporation of a silicon nitride (SiN) feedback circuit with two ring resonators for filtering.
• Utilizing stepped-heterodyne optical complex spectrum analysis to characterize the laser output.

Main Results:

• Achieved self-mode-locking in the hybrid integrated laser.
• Demonstrated a predominantly frequency-modulated (FM) field output.
• Observed that the SiN filter limits the optical comb bandwidth, concentrating power into fewer lines.

Conclusions:

• The hybrid integrated laser design enables self-mode-locking and FM output, suitable for high-power microwave photonic applications.
• The integrated ring resonator filter effectively manages optical comb bandwidth and power distribution.