Optical waveguides – Planar optical waveguide
Reexamination Certificate
1999-09-08
2001-07-03
Spyrou, Cassandra (Department: 2872)
Optical waveguides
Planar optical waveguide
C385S130000
Reexamination Certificate
active
06256442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an integrated optical waveguide device in which thermal spectral shifts are inhibited, and particularly to athermalized optical waveguide devices in which the light transmitting properties are insensitive to temperature variations and fluctuations.
2. Technical Background
Integrated optical waveguide devices, such as integrated optical circuits, combine miniaturized waveguides and optical devices into a functional optical system incorporated onto a small planar substrate. Such integrated optical waveguide devices are utilized in optical communications systems, usually by attaching optical waveguide fibers, that transmit light signals, to the integrated optical waveguide device as inputs and outputs. The integrated optical waveguide device performs a function or process on the transmitted light in the optical communications system. Such devices provide good performance at consistent standard room temperatures but exhibit thermal spectral shifts (d&lgr;/dT, measured in nm/° C.) and related poor performance when used in environments where they are exposed to thermal variations and fluctuations in temperature. Integrated optical devices which incorporate interferometers, particularly interferometers based on the division of amplitude, such as Mach-Zehnder interferometers which depend on amplitude splitting of a wavefront, can be used as transmitting filters, sensors, and wavelength multiplexing and demultiplexing devices.
Integrated optical devices which incorporate an interferometer are particularly useful as a wavelength division multiplexer/demultiplexer. Such wavelength multiplexer/demultiplexers may incorporate a phased array comprised of a plurality of different waveguide core arms.
It has been found that the use of integrated optical waveguide devices is limited by their temperature dependence. In such integrated devices, thermal spectral shifts of greater than or of the order of about 0.001 to 0.01 nm/° C. at a transmitting wavelength of 1550 nm can limit their usefulness in environments of differing temperature.
SUMMARY OF THE INVENTION
Accordingly the present invention is directed to an optical waveguide device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the compositions, structures, design, and methods particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention provides an athermalized integrated optical waveguide device having at least two waveguide core arms with the core arms cladded with a waveguide cladding composition, preferably a silica glass that has a boron concentration different than the cores. Preferably the at least two waveguide core arms are of the same core composition, preferably a silica glass.
In another aspect, the invention includes an athermal optical waveguide device having at least two waveguide core arms which are comprised of path segments having different waveguide core dimensions.
A further aspect of the invention is to provide a method of athermnalizing an optical waveguide device by forming at least two waveguide core arms having path segments of unequal waveguide core widths and cladding the waveguide core arms with a cladding composition having a concentration of boron different than the waveguide core arms.
It is to be understood that both the foregoing general description, and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention.
REFERENCES:
patent: 4781424 (1988-11-01), Kawachi et al.
patent: 6118909 (2000-09-01), Chen et al.
patent: 0849231 (1998-06-01), None
Nolan Daniel A.
Trouchet Denis M.
Weidman David L.
Alden Philip G.
Cherry Euncha
Corning Incorporated
Spyrou Cassandra
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