This paper analyses losses caused by the misalignment of two fibers joined in a splice. We consider the possibility that the two fibers of different dimensions are separated in longitudinal direction and are tilted or offset with respect to each other. Central to our discussion is the observation that the modes of single-mode fibers are very nearly gaussian in shape regardless of the fiber type step-index or graded-index. The splice losses are thus related to the corresponding losses of gaussian beams. We specify the relation between the actual mode field and the gaussian beam that matches this field optimally. The trade-off between slice tolerances with respect to tilt and offset is expressed as an “uncertainty principle. “ Because of the near-gaussian nature of single-mode fiber fields, our results are immediately applicable to the excitation of single-mode fibers by gaussian-shaped laser beams.

Loss analysis of single-mode fiber splices

A theoretical characterization of the guided‐mode resonance properties of planar dielectric waveguide gratings is presented. Efficient exchange of energy between forward and backward propagating diffracted waves is shown to be possible with smooth line shapes. The linewidths of the resonances can be controlled by the grating modulation amplitude. Due to the inherent separation between the TE and TM modes associated with the waveguide grating, these elements can provide polarization separation. Applications to polarization sensitive filtering and to electro‐optic switching are suggested. The guided‐mode resonance filter represents a basic new optical element.

New principle for optical filters

We report simultaneous transmission of six spatial and polarization modes, each carrying 40 Gb/s quadrature-phase-shift-keyed channels over 96 km of a low-differential group delay few-mode fiber. The channels are successfully recovered by offline DSP based on coherent detection and multiple-input multiple-output processing. A penalty of ;28 dB.

Mode-Division Multiplexing Over 96 km of Few-Mode Fiber Using Coherent 6 $\,\times\,$ 6 MIMO Processing

The possibility of using Bragg reflection in a cylindrical fiber to obtain lossless confined propagation in a core with a lower refractive index than that of the cladding medium is proposed and analyzed.

Theory of Bragg fiber

https://hal.archives-ouvertes.fr/hal-00004659/document

Surface electromagnetic waves thermally excited: Radiative heat transfer, coherence properties and Casimir forces revisited in the near field

The asymmetric slab waveguide weakly guiding optical fibers coupled mode theory applications of the coupled mode theory coupled power theory theory of the directional coupler grating-assisted direction couplers approximate and numerical methods nonlinear effects.

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Dietrich Marcuse

Papers

Theory of dielectric optical waveguides

Theory of Dielectric Optical Waveguides