Phasar athermalization using a slab waveguide
AssigneeCorning Incorporated
InventorsSteven B. Dawes, Nikolaus Boos, Sophie Vallon
Life of this patent
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Abstract
A passive temperature-compensated integrated optical component having an array of adjacent waveguides, and a slab waveguide located within a groove at an intermediate section of the array. The waveguides have an index of refraction that increases with increasing temperature, and the slab waveguide has an index of refraction that decreases with increasing temperature. The slab waveguide compensates for a temperature-induced change in the refractive index of the waveguides to maintain a generally constant optical path difference between the adjacent waveguides over a temperature range.
Claims13
A temperature-compensated integrated optical component fabricated on a substrate, the substrate having an upper surface, the substrate either including an undercladding disposed on the upper surface thereof or the substrate acting as the undercladding itself, the temperature-compensated integrated optical component comprising:
- an optical phased array disposed on the substrate, the optical phased array defined by a plurality of waveguide cores and an overcladding disposed on the plurality of waveguide cores such that the plurality of waveguide cores are interposed between the undercladding and the overcladding, the plurality of waveguide cores having an index of refraction that increases with increasing temperature, the optical phased array having an intermediate section defining a groove, each of the plurality of waveguide cores having a lower surface and an upper surface, the groove extending downwardly to a depth lower than the bottom surface of the waveguide cores;
- and
- a slab waveguide located within the groove at the intermediate section of the optical array, the slab waveguide including
- an undercladding layer disposed at the bottom of the groove, the undercladding layer having an upper surface located in a plane generally coinciding with the lower surfaces of the plurality of the waveguide cores,
- a slab core layer disposed over the undercladding layer of the slab waveguide, the slab core layer having an index of refraction that decreases with increasing temperature to compensate for a temperature-induced change in the refractive index of the plurality of waveguide cores and maintain a generally constant optical path difference between the adjacent ones of the plurality of waveguide cores over a temperature range, the slab core layer having an upper surface in a plane generally coinciding with the upper surfaces of the plurality of waveguide cores, and
- an overcladding layer disposed over the slab core layer.
A method for making a temperature-compensated integrated optical component comprising the steps of:
- providing an optical component including a substrate and a plurality of waveguide cores of different lengths, the substrate either including an undercladding disposed thereon or the substrate acting as the undercladding itself, the plurality of waveguide cores disposed on the undercladding, an intermediate section of the optical component defining a groove which extends downwardly to a depth lower than the bottom surface of the waveguide cores and which divides each of the plurality of waveguide cores into a first waveguide core segment and a second waveguide core segment separated from the first waveguide core segment by a free space;
- and
- forming an undercladding within in the groove, the undercladding within the groove having an upper surface located in a plane generally coinciding with the lower surfaces of the plurality of waveguide cores;
- forming a slab core within the groove, the slab core having an index of refraction that decreases with increasing temperature to compensate for a temperature-induced change in the refractive index of the plurality of waveguide cores and maintains a generally constant optical path length difference between adjacent ones of the plurality of waveguide cores over a temperature range.
Dependencies are inferred from the claim text.