Patent ID: 7778498

Claim:
A method for generating a cylindrically polarized beam, comprising: (a) providing an optical signal comprising a fundamental LP 01 mode; (b) providing an input optical fiber that supports propagation of the optical signal in the LP 01 mode; (c) using a mode converter device to convert the LP 01 mode input into a higher-order LP 11 mode output, the higher-order LP 11 mode comprising a linear combination of cylindrically polarized TM 01 and TE 01 modes, and mixed HE 21 (even) and HE 21 (odd) modes; (d) causing the LP 11 mode output to propagate through a phase-engineered fiber coupled to the mode converter device, wherein the phase-engineered fiber has a refractive index profile that comprises a steep refractive index step proximate to a peak amplitude of a mode intensity profile of the LP 11 mode output, such that at least one of the cylindrically polarized modes has an effective refractive index sufficiently separated from effective refractive indices of the mixed modes; (e) selecting the at least one separated cylindrically polarized mode; and (f) providing the at least one separated cylindrically polarized mode as an output.