Polarization locked vector solitons and axis instability in optical fiber

Area of Science:

• Nonlinear optics
• Fiber optics

Background:

• Polarization-locked vector solitons are optical phenomena that maintain their polarization state.
• Birefringence in optical fibers can disrupt polarization states.
• Understanding the interplay between nonlinearity and birefringence is crucial for soliton stability.

Purpose of the Study:

• To experimentally observe and characterize polarization-locked vector solitons in an all-fiber laser.
• To investigate the conditions under which solitons can maintain their polarization state despite birefringence.
• To provide a physical explanation for the observed soliton states and their stability.

Main Methods:

• Experimental observation of polarization evolution in an all-fiber laser.
• Characterization of two distinct fixed-polarization states.
• Measurement of relative phase and amplitude between orthogonal polarization components.
• Analysis of the influence of birefringence on soliton states.

Main Results:

• Two distinct polarization states were observed: an elliptically polarized state for low birefringence and a linearly polarized state for higher birefringence.
• The elliptically polarized state exhibits a relative phase of +/-pi/2 and its amplitude varies linearly with birefringence.
• The linearly polarized state is attributed to fast axis instability.
• Complete characterization and physical explanation of both states were provided.

Conclusions:

• Polarization-locked vector solitons were experimentally confirmed in optical fiber lasers.
• The study elucidates the conditions and mechanisms governing soliton stability in the presence of birefringence.
• A comprehensive understanding of these soliton states and their stability is established.