Abstract: A method and apparatus for constructing an optical wavelength-routing network in which each network node is a dynamic add-drop multiplexer (OADM) with minimized spectral filtering effect on pass-through channels and survivability upon power failure. By using cascaded tunable reflection filters as the building blocks, strictly add-drop non-blocking OADMs for single input/output fibers, double input/output fibers, and 3 input/output fibers can be constructed for application to unidirectional and bidirectional ring networks and mesh networks of arbitrary degree. Methods and apparatus for minimizing various types of out-of-band and in-band crosstalk occurring within the dynamic OADMs are also described.

Abstract: A method and apparatus for constructing an optical wavelength-routing network in which each network node is a dynamic add-drop multiplexer (OADM) with minimized spectral filtering effect on pass-through channels and survivability upon power failure. By using cascaded tunable reflection filters as the building blocks, strictly add-drop non-blocking OADMs for single input/output fibers, double input/output fibers, and 3 input/output fibers can be constructed for application to unidirectional and bidirectional ring networks and mesh networks of arbitrary degree. Methods and apparatus for minimizing various types of out-of-band and in-band crosstalk occurring within the dynamic OADMs are also described.

Abstract: A method and apparatus for constructing a modular and easily upgradable optical network node using the technique of wavelength-division multiplexing (WDM). According to the present invention, a WDM point-to-point link end node can be modularly upgraded in the number of wavelength channels or upgraded to a ring network node; both without requiring equipment internal rewiring.

Abstract: This invention provides methods and apparatus for achieving wavelength sorting multiplexer/demultiplexer and its application to the implementation of planarized dynamic wavelength routing. Using integrated arrayed-waveguide gratings, sorting can be achieved by two configurations. In the first configuration channel wavelengths are properly selected and launched into prearranged input waveguides of an arrayed-waveguide grating such that channels at the same wavelength and from all inputs will be demultiplexed and routed to adjacent outputs. Operated in the reverse direction, the same device becomes a sorting multiplexer. The second configuration achieves wavelength sorting by using the cascade of multiple arrayed-waveguide gratings and can also be operated as a demultiplexer or a multiplexer. Combined with space switches, the wavelength sorting multi/demultiplexer are utilized to implement the planarized channel-selective dynamic wavelength router.

Abstract: The present invention relates to a waveguide taper. The waveguide taper has a first end and a second end for being coupled with a fiber. The core has an overall width that progressively increases from the waveguide end toward the fiber end such that the width of the fiber end of the taper corresponds to the diameter of the core of the fiber. Side-gaps are disposed in the sides of the core and extend into the core but not across the entire width of the core. The depth of the side-gaps progressively increases from the waveguide end to the fiber end of the taper. In one embodiment, the side-gaps may be aperiodically and/or randomly disposed along the length of the taper and the side-gaps can be disposed at different angles to a direction of light propagation along a length of the core.

Abstract: 1.times.2 and more complex switching operations use routing corresponding with guides produced by heating with a laterally-homogeneous layer. Strip heaters, in contact with a silica-based sandwich structure, thermally increase refractive index to define laterally-constrained cores within the center layer.

Abstract: The invention relates to a fixed gap waveguide taper. The waveguide taper has a first end and a second end for being coupled to a fiber. The waveguide taper includes a plurality of segments extending from the first end toward the second end. The segments include a gap portion and a core portion. In the present invention, the gap portion remains fixed at a constant length s throughout the entire waveguide taper. In contrast, the core section of the segment varies from the waveguide end of the taper toward the fiber end of the taper. In particular, the core section in each of the segments progressively decreases in length from the waveguide end toward the fiber end of the taper. Accordingly, the length of the segment .LAMBDA. progressively decreases from the waveguide end toward the fiber end of the taper.

Abstract: In accordance with the invention, an optical fiber phase shifter comprises a length of asymmetrical optical fiber disposed perpendicular to a magnetic field for providing a non-reciprocal phase shift. Preferably the fiber is wound in a circular coil and exposed to an axial field as from a pancake magnet. In an isolator, the fiber length and magnet strength are chosen to provide non-reciprocal phase shifts of .+-.45.degree. or .+-.90.degree.. The isolator including the phase shifter can be any of several configurations.