Effective Mode Field Diameter Research Articles

Different Graded Refractive Index Fiber Profiles Design for the Control of Losses and Dispersion Effects

Abstract This paper has presented the basic infrastructure of different multilayer graded index fiber profiles design. The optimum graded refractive index fiber profile design for the control of total Losses and dispersion effects are considered. The trade-off between different refractive index fiber profiles is realized in order to achieve loss and dispersion effects management. It is evident that the proposed first optical fiber has presented lower dispersion and splice loss than other proposed fibers. As well as the proposed third optical fiber outlines lower effective mode field diameter and micro bending loss than other proposed fibers. Dominant mode, cutoff wavelength and international telecommunication union-telecommunication (ITU-T) values for each fiber are examined based on finite difference method.

Effective mode-field diameter for few-mode fibers for considering splice loss characteristics.

We experimentally and numerically investigate the applicability of the conventional near-field pattern, far-field pattern (FFP), and variable aperture (VA) methods for measuring the effective mode-field diameter (MFD) of the higher-order modes, which can be used for accurately evaluating splice loss. We confirmed that the variation in the MFD values obtained with the FFP and VA methods can be converged by considering the minimum scanning angle and the minimum aperture angle, respectively, for both fundamental and higher-order modes. We reveal that the FFP and VA methods provide adequate effective MFD values for few-mode fiber (FMF), which can be used for evaluating the splice loss based on the conventional Gaussian fitting model. We also show the applicability of the effective MFD to four linearly polarized mode FMFs for considering the splice loss characteristics of each mode.

Effective Mode Field Diameter for LP11Mode and Its Measurement Technique

The effective mode field diameter (MFD) for the second-order (LP11) mode in two-mode fibers is determined to allow estimation of the coupling efficiencies at a splice with axial misalignment. Simulations are performed to verify its validity. In addition, we propose a novel technique for measuring the effective MFD distribution for the LP11 mode along two-mode fibers. The technique is based on optical time-domain reflectometry; it conducts measurements in the two-mode region of test fibers and individually observes the LP01 and LP11 modes of the backscattered light. Its feasibility is demonstrated experimentally.

Seven-core neodymium-doped phosphate all-solid photonic crystal fibers

We demonstrate a single-mode seven-core Nd-doped phosphate photonic crystal fiber with all-solid structure with an effective mode field diameter of 108 μm. The multicore fiber is first theoretically investigated through the finite-difference time-domain method. Then the in-phase mode is selected experimentally by a far-field mode-filtering method. The obtained in-phase mode has 7 mrad mode field divergences, which approximately agrees with the predicted 5.6 mrad in seven-core fiber. Output power of 15.5 W was extracted from a 25 cm fiber with slope efficiency of 57%.

Performance study of different step index multi-clad fiber for broadband application

In this paper, the analytical study of the performance characteristics like group delay, effective mode field diameter (MFD) and dispersion curves of an optical fiber having various cladding layers are presented. The proposed six structures of optical fiber have three parts, namely core with highest refractive index dielectric material, inner claddings and outer cladding. The group delay, MFD and dispersion depend on the number of cladding in optical fiber. The zero dispersion wavelengths vary with number of cladding increases or decreases. The guided modes and propagation wave vectors can be evaluated by using a determinant which is constructed by the boundary matched method. The cutoff conditions of modes for varying number of inner claddings are compared. The analysis shows that the propagation property can be controlled of an optical fiber by increasing the number of inner claddings and diameter of the core. These claddings provide a degree of freedom to control the modes and other characteristics of the fiber.

Parameter space for the collective laser coupling in the laser fusion driver based on the concept of fiber amplification network

Collective laser coupling of the fiber array in the inertial confinement fusion (ICF) laser driver based on the concept of fiber amplification network (FAN) is researched. The feasible parameter space is given for laser coupling of the fundamental, second and third harmonic waves by neglecting the influence of the frequency conversion on the beam quality under the assumption of beam quality factor conservation. Third harmonic laser coupling is preferred due to its lower output energy requirement from a single fiber amplifier. For coplanar fiber array, the energy requirement is around 0.4 J with an effective mode field diameter of around 500 μm while maintaining the fundamental mode operation which is more than one order of magnitude higher than what can be achieved with state-of-the-art technology. Novel waveguide structure needs to be developed to enlarge the fundamental mode size while mitigating the catastrophic self-focusing effect.

Chromatic dispersion in rectangular geometry waveguides

We calculate the chromatic dispersion of rectangular geom- etry waveguides and focus on the conditions for obtaining zero chromatic dispersion at a wavelength of 1.55 mm. We consider single-mode waveguides fabricated from six distinct compositions of silica-based ma- terials whose dispersive characteristics are modeled by use of a Sell- meier relation. Our analysis takes account of the two transverse dimen- sions of the guiding channel and provides for a determination of the dispersion coefficientb9 as a function of the values of both dimensions. The results allow us to compute a spectrum of values of the two trans- verse widths for which the total dispersion is zero. By definition of an effective mode field diameter for a channel waveguide we are able to discuss the end-to-end coupling of such a waveguide to a commercial single-mode fiber. © 1999 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(99)02401-0)