Nonlinear mode coupling in birefringent fiber: application to optical pulse reshaping

• Published in: Applied physics letters 1984-10, Vol.45 (8), p.838-840
• Main Authors: KITAYAMA, K, KIMURA, Y, SEIKAI, S
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.95419

It is theoretically shown that intensity dependent mode coupling is induced by nonlinear birefringence between two orthogonally polarized modes in optical fibers in such way that the weak light field polarized along the slow axis of the birefringent fiber couples more strongly to the other mode having the perpendicular polarization than to the strong light field. By utilizing the mode coupling property it is possible in a birefringent single-mode fiber to isolate the optical pulse launched, say, in the LPx01 mode from the precursor and tailing edges or weak background by coupling them to the LPy01 mode. This will readily lead to the application of birefringent fibers to optical pulse compression. In this scheme of pulse reshaping, the loss of the LPy01 mode is required to be much larger than that of the LPx01 mode in order to avoid the unnecessary coupling back to the main mode.