The invention describes two types of multimode optical waveguides having special dip in the refractive index profile of their core providing conditions for propagation of a higher order mode with sharp central peak which field carries considerable part of the mode energy, while the fields of all other modes in the waveguide are mostly concentrated outside of this central peak region. The waveguide of the first type guides the mode only with one central peak while the mode in the waveguide of the second type has also an additional peak at the interface between the waveguide core and cladding providing a possibility to detect any influence on the mode field in its outer region by measuring the signal in the central peak of the mode. The useful properties of these two kinds of modes can be employed for designing new wavelength selective waveguide components for optical communications and sensors applications: an optical waveguide modulator, amplitude and interferometric sensors for different applications, bistable nonlinear components for logic switching and optical memory, wavelength selective chemical sensors of both amplitude and interferometric type, etc. Employing a material exhibiting electro-optical properties provides a possibility of tuning of the components proposed as well as fabrication of the sensors of electric fields.
