Patent ID: 6347166
Filing Date: 2002-02-12
Classification: G02B

Abstract:
A device for superposing optical signals of different wavelengths, comprising:an input free beam coupler provided with a first free beam section; an output free beam coupler provided with a second free beam section; a light guide grid comprising phase shift light guides for coupling the first and second free beam sections; a first input light guide unit for propagating at least one wavelength and connected to the input free beam coupler; at least one second input light guide unit for propagating at least one wavelength and coupled to the first free beam section; an output light guide unit coupled to the output free beam coupler and comprising a plurality of output light guides; the input sections of the first and at least second input light guide units being arranged and dimensioned relative to an axis of symmetry of the output free beam section in accordance with formula Î˜IN(i)=mns&it;d&it;{Î»(i)-Î»c[1+1nc&it;â€ƒ&it;&dd;nc&dd;Î»&RightBracketingBar;Î»=Î»c&it;(Î»(i)-Î»c)]}-Î˜OUT(i)&lgr;(i) being the wavelength propagating in an input waveguide of the input light guide units; &lgr;c being the central wavelength of the device; m being the order of diffraction of the light guide grid; nc being the effective index of refraction of the phase shift light guide; ns being the effective index of refraction of the free beam sections; d being the grid constant (pitch) of the phase shift light guides at the transition to the second output free beam section; &ominus;(i)IN being the incident coupling angle of the ith input light guide relative to an input axis of symmetry of the first input free beam section and &ominus;(i)OUT being the output angle of divergence relative to the axis of symmetry of the output free beam section, such that each output light guide is energized by at least two optical signals of different wavelengths propagating in the first and at least second input light guide units.