Monolithically integrated InP-based DBR lasers with an intra-cavity ring resonator

Area of Science:

• Photonics and Semiconductor Lasers
• Integrated Optics
• Optical Engineering

Background:

• Distributed Bragg Reflector (DBR) lasers are crucial in optical communication.
• Improving side-mode suppression ratio (SMSR) and intrinsic linewidth is key for laser performance.
• Monolithic integration on InP platforms offers advanced functionalities.

Purpose of the Study:

• To investigate the impact of an intra-cavity ring resonator on DBR laser performance.
• To assess improvements in SMSR and intrinsic linewidth using InP active-passive integration.
• To validate experimental results with theoretical spectral models.

Main Methods:

• Fabrication of monolithically integrated extended cavity multi-section DBR lasers with an intra-cavity ring resonator.
• Characterization of laser output spectrum and side-mode suppression ratio (SMSR) across varying optical amplifier currents.
• Measurement of frequency noise power spectral density and intrinsic linewidth at different output power levels.

Main Results:

• Experimental laser output spectra align well with theoretical steady-state spectral model calculations.
• Achieved SMSR ranging from 60 to 70 dB under various operating conditions.
• Recorded a minimum intrinsic linewidth of 63 kHz and compared it with theoretical predictions.

Conclusions:

• The integrated ring resonator effectively enhances DBR laser performance, particularly SMSR and linewidth.
• The study demonstrates the potential of InP integration platforms for high-performance laser devices.
• Further linewidth reduction is feasible with advancements in photonic integration technology.