Equilibrium mode distribution

About: Equilibrium mode distribution is a research topic. Over the lifetime, 928 publications have been published within this topic receiving 14939 citations.

Simultaneous single mode and multi-mode propagation of signals in a double clad optical fiber

Abstract: An optical amplifier having a suitable length of Er/Yb co-doped double clad optical fiber is used to amplify an input optical signal. The inner clad of the double clad optical fiber supports the propagation of a multi mode signal used to excite Er/Yb co-dopants in the double clad optical fiber. Simultaneously, a single mode signal launched from a single mode laser pump co-propagates with the input optical signal in the core of the optical fiber. In this model, single mode light travels in the single mode core region and the multi mode pump light is mainly in the clad region. The interaction between the two laser pumps is negligible.

A Coupled-Waveguide TE/TM Mode Splitter

Abstract: A novel channel waveguided TE/TM mode splitter is presented. This splitter can spatially separate the TE and TM mode components and is compatible with single mode fiber systems. The operation principle is as follows. Two straight waveguides are formed closely parallel to each other on c-plate LiNbO3 by preferential Ti diffusion. An Al strip loaded on waveguide 2 induces a large change in the propagation constant for the TM mode, so that the TM mode component, fed into waveguide 1, cannot couple to waveguide 2 ("straight-through state"). By applying external voltages V1 and V2 to the two planar electrodes, formed on waveguide 1 with an Al2O3 buffer layer in-between, a complete power transfer from waveguide 1 to waveguide 2 takes place for the TE mode ("crossover state"). Less than -20 dB crosstalk was realized at 1.15 µm wavelength for V1=20 V and V2=-15 V. The insertion loss was 1.7 dB.

Characteristics of phase-matched sum-frequency light in optical fibres

Abstract: Characteristics of phase-matched sum-frequency light in optical fibres is investigated to determine the input power dependence and fibre length dependence. The output power at 0.54 ?m increases in proportion to the square root of the input power, increasing almost exponentially with increases in the fibre length from 4 m to 17 m and becoming nearly constant above 17 m.

Passive mode-locking using multi-mode fiber

Abstract: The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that when the higher order mode content exceeds -27 dB, the maximum stable single-pulse energy is significantly reduced. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg-Landau equations (CGLEs). Simulations show that stable and robust mode-locked pulses can be produced. The maximum stable single pulse energy is found to increase with higher order mode filtering. This work demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers, and gives a quantitative estimate of what constitutes effectively single-mode operation. Robust, distributed higher order mode filtering is necessary to maximize single-pulsing energy.