Patent ID: 6535672
Filing Date: 2003-03-18
Classification: G02B,G02F

Abstract:
A multi-mode interference optical device comprising:a first waveguide having an input end and an output end and having a glass core; a second waveguide having a hybrid core including a first core section of a first thermo-optically active material and a second contiguous core section of glass, the first material and the glass having substantially different thermo-optic coefficients, the second waveguide having a section juxtaposed to and abutting sidewise the glass core of the first waveguide, the juxtaposed section shaped and dimensioned to enable multi-mode interference between beams propagating in the first and the second waveguide when refractive indices of the first and the second waveguide are equal; a cladding covering at least some of the hybrid core and some of the first waveguide glass core; and a heater coupled to the cladding in thermal contact with at least the first core section for relatively varying the refractive index difference between the first section of the hybrid core and the glass core in the first waveguide in a controlled manner, so that the refractive index difference between the glass and the first material is variable between substantially about zero, whereby MMI coupling can take place in the optical device, and some number different than zero in the presence or absence of applied heat.