Simple and complex square waves in an edge-emitting diode laser with polarization-rotated optical feedback

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Nonlinear Dynamics

Background:

• Edge-emitting diode lasers are crucial optoelectronic devices.
• Delayed optical feedback can induce complex dynamics.
• Polarization control is essential for laser stability and functionality.

Purpose of the Study:

• To investigate the impact of rotated polarization feedback on diode laser dynamics.
• To identify and characterize new periodic, polarization-modulated solutions.
• To understand the conditions leading to these novel dynamic regimes.

Main Methods:

• Numerical simulations of diode laser models.
• Experimental validation using edge-emitting diode lasers.
• Analysis of bifurcation structures and dynamic waveforms.

Main Results:

• Observed coupling of natural laser modes into orthogonal, unsupported modes via polarization-rotated feedback.
• Identified a class of periodic, polarization-modulated solutions, including square waves.
• Determined that strong feedback and low differential losses in the unsupported mode favor these solutions.

Conclusions:

• Delayed optical feedback with specific polarization rotation can lead to unique, stable periodic dynamics in diode lasers.
• The observed square wave and complex periodic solutions offer new avenues for laser control.
• Understanding these nonlinear dynamics is key for designing advanced laser systems.