Methods of fabricating grating assisted coupler devices
US6169830A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 1998 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Aug 4, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/2835
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Advantageous methodologies are disclosed for embedding periodic patterns in optical waveguide elements such as optical fibers. Polarization independence in an elongated waist region of an add/drop coupler can be established by measuring polarization characteristics during fusion and elongation, and controlling the elongation to impart a cross-sectional shape, such as a hybrid dumbbell-ellipsoid. Polarization dependence can also be minimized by angular deformation of the elements along the light transmissive axis. To write a pattern, an element having potential photosensitivity is markedly photosensitized in a hydrogen or deuterium environment pressurized to about 1000 to 5000 psi and a scanning UV beam that is transmitted through a photo mask and impinges on the coupler waist as the in-diffused gas is constantly replenished. Dimensional variations in the element which can affect spectral bandwidth are sensed by writing a preliminary test pattern in the element and then locally measuring the spectral properties of the test pattern and adjusting the local levels of background index of refractions so that the modal index of refraction is substantially constant along the length of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.