Coupling efficiency of butt-joined planar waveguides with simultaneous tilt and transverse offset

Abstract

An efficient method has been proposed for evaluating the junction loss between two nonidentical arbitrarily graded-index planar optical waveguides caused by simultaneous transverse and angular misalignments. The salient feature of the method is an exact representation of the modal fields which is particularly adapted to loss evaluation at imperfect junctions. The power transmission coefficient at the junction is expressed via the overlap integral method as a weighted sum of simple Laguerre-Gaussian functions, the weight factors being determined by solving a linear matrix eigenvalue problem. The present formulation has a very broad scope of validity and can be used for the modal analysis of integrated optical planar components such as waveguide lenses and to estimate the coupling efficiency of more practical fiber-to-channel butt-joints. The method can also be used to test the accuracies of other approximate methods such as those based on the Gaussian approximation of the lowest order planar waveguide mode.

Mode coupling at the splice of diverse optical fibers

“…Generally, the coupling coefficient η mn of injected mode m with excited mode n is determined by an overlap integral of interacting mode fields, and its scalar form under cylindrical coordinates is described by following wellknown formula [1][2][3][4][5][6][7][8][9][10][11][12][13][14] : …”

“…It is widely applied for estimation of insertion loss and reflection at splice of the same type optical fibers with non-identical technologic parameters [1][2][3][4][5][6][7] , modeling and research for influence of optical signal launch conditions on optical waveguide mode structure excitation [8][9][10][11] , including under modeling for a few-mode optical pulse propagation over multimode fibers [12][13][14] . Mentioned method is also applicable for analysis of mode mixing and power diffusion processes due to optical fiber irregularities and micro-/macro bending.…”

“…As a result, it permits to obtain analytical formulas for the overlap integral (3) by applying simple approximation expressions or by a particular function series expansion for the fundamental mode field representation. These algorithms are widely used for analysis of the single mode fiber splices [2][3][4][5][6]8,10,11 .…”

Modeling and Simulation of Piecewise Regular Multimode Fiber Links Operating in a Few-Mode Regime

“…As a result, it permits obtaining analytical formulas for the overlap integral (34) by applying simple approximation expressions or by a particular function series expansion for the fundamental mode field representation. These algorithms are widely used for analysis of the single mode fiber splices [25,[117][118][119][120][121][122][123].…”

“…It is widely applied for estimation of insertion loss and reflection at the splices of the same type optical fibers with nonidentical technologic parameters [117][118][119][120][121], modeling, and research of the influence of launch conditions on optical waveguide mode composition excitation [25,[122][123][124] including the modeling of a fewmode optical signal propagation over multimode fibers [4,8,10]. Generally, the coupling coefficient of injected mode with excited mode is determined by the overlap integral of interacting mode fields [4,8,10,[117][118][119][120][121][122][123][124]:…”