Active region-less modulator and method

A polymer modulator comprising:

• a semiconductor substrate with an insulating layer on an upper surface of the substrate;
• a passive waveguide core defined over the insulating layer and having a first passive region defining a modulator light input, a second passive region defining a modulator light output, and a central passive portion spanning an active region optically coupling the first passive region and the second passive region to form a continuous passive waveguide core between the light input and the light output;
• the passive waveguide core in both the first passive region and the second passive region being surrounded by cladding;
• the cladding surrounding the passive waveguide core in both the first passive region and the second passive region having a first refractive index, the passive waveguide core in both the first passive region and the second passive region having a second refractive index, and the second refractive index being at least 0.01 higher than the first refractive index;
• a lower cladding layer partially surrounding the passive waveguide core in the active region, the refractive index of the passive waveguide core in the active region is at least 0.01 higher than the refractive index of the lower cladding layer;
• the active region further including a shaped electro-optic polymer active core component carried within a cavity formed in the passive central portion and abutting the passive waveguide core in the active region, the shaped electro-optic polymer active core component being polled to align dipoles and promote modulation of light;
• shaped electro-optic polymer active core component including opposing ends that are each tapered horizontally and vertically, forming adiabatic transition areas with the passive central portion;
• and
• the active region further including an upper cladding layer joined with the lower cladding layer of sol-gel in the active region to surround the shaped electro-optic polymer active core and the passive waveguide core in the active region, the refractive index of the waveguide core in the active region is at least 0.01 higher than the refractive index of the in the upper cladding layer.

A method of fabricating a polymer modulator comprising the steps of:

• providing a semiconductor substrate and forming an insulating layer on an upper surface of the substrate;
• defining a passive waveguide core on the insulating layer with a first passive region including a modulator light input, a second passive region including a modulator light output, and a central passive portion spanning an active region optically coupling the first passive region and the second passive region to form a continuous passive waveguide core between the light input and the light output, and depositing material in both the first passive region and the second passive region to form the passive waveguide core;
• depositing a cladding in both the first passive region and the second passive region surrounding the passive waveguide core, the cladding surrounding the passive waveguide core in both the first passive region and the second passive region having a first refractive index, the material included in the passive waveguide core in both the first passive region and the second passive region having a second refractive index, and the second refractive index being at least 0.01 higher than the first refractive index;
• depositing a lower cladding layer in the active region, forming a passive central portion having a cavity in the active region on the lower cladding layer to form the passive waveguide core in the active region, and the refractive index of the passive waveguide core in the active region is at least 0.01 higher than the refractive index of the sol-gel in the lower cladding layer;
• and
• forming a shaped electro-optic polymer active component within the cavity, abutting the passive waveguide core in the active region, the shaped electro-optic polymer active component having a length that extends only within a modulation area defined by modulation electrodes and including opposing ends that are each tapered horizontally and vertically, forming adiabatic transition areas with the passive central portion.