Enhanced feedback sensitivity suppression in phase-detuned tunable lasers with high-Q Vernier-effect based ring...

The feedback sensitivity of a tunable laser with a highly wavelength-selective reflector using a high-Q Vernier-effect based ring resonator structure is examined through both experimental and simulation work. The study demonstrates that by properly tuning the amplitude and phase of the reflector, the laser exhibits reduced feedback sensitivity, leading to improved laser performance under external optical feedback. The onset of deterioration in the quantum-well-based laser due to optical feedback, characterized by excess relative intensity noise (RIN), is suppressed through red detuning to a feedback level above -13 dB, over 5 dB higher than for the non-detuned laser state. The study further characterizes the high-speed data transmission performance of the laser, showing that the red-detuned ring resonator based tunable laser offers enhanced stability against feedback. Simulation results confirm that the phase-detuned tunable laser, with its lower feedback coefficient, outperforms traditional distributed Bragg reflector (DBR) lasers, particularly under detuning conditions.