Uniform core field in symmetrical planar waveguides and circular fibers with nonlinear claddings

It is known that no uniform electric field profile exists in a planar linear waveguide. The uniform core field can be shown to exist in symmetrical planar waveguides and circular fibers with nonlinear claddings. Theoretical analysis and numerical calculations show that when the modal index equals to the core refractive-index, the core field becomes uniform at an appropriate optical power. The analysis for a step-index circular fiber with nonlinear cladding has also shown that the core field becomes uniform under similar conditions. The occurrence of a uniform field in a waveguide core may be considered to have promising applications in waveguide, optoelectronic and photonic devices.