Abstract: Two techniques are disclosed for writing waveguides between laser diodes and an optical fiber such that the laser diodes are aligned with their respective waveguide facets. The first technique utilizes a light sensitive polymer, such as a ultra-violet (UV) cross-linkable polymer. A precision writing system locates the light emitting centers of the laser diodes and writes the waveguide circuit by exposing the waveguiding regions with the appropriate light. The unexposed areas of the core layer are developed with a solvent and removed. The entire device is then encapsulated with a low-index cladding polymer. The second technique utilizes an active polymer approach in which waveguide regions are formed when the writing beam aligns the dipole molecules in the polymer to cause a change in the refractive index of the polymer.

Abstract: Two techniques are disclosed for writing waveguides between laser diodes and a fiber channel such that the laser diodes are aligned with their respective waveguide facets. The first technique utilizes a light sensitive polymer, such as a ultra-violet (UV) cross-linkable polymer. A precision writing system locates the light emitting centers of the laser diodes and writes the waveguide circuit by exposing the waveguiding regions with the appropriate light. The unexposed areas of the core layer are developed with a solvent and removed. The entire device is then encapsulated with a low-index cladding polymer. The second technique utilizes an active polymer approach in which waveguide regions are formed when the writing beam aligns the dipole molecules in the polymer to cause a change in the refractive index of the polymer.

Abstract: An ionization chamber for use in a smoke detector includes first and second outer electrodes and a non-reflective center electrode. The non-reflective center electrode can be formed as a metal electrode having a non-reflective coating or as a non-reflective, conductive plastic elements. The ionization chamber can be incorporated into combination smoke detector which includes a photoelectric sensor. A non-reflective center electrode, associated with the ion-type sensor is symmetrically located in the detector and displaced from the photoelectric sensor.