Switchable optical components
View Patent ↗This invention relates to a number of components, devices and networks involving integrated optics and/or half coupler technology, all of which involve the use of electronically switchable Bragg grating devices and device geometries realized using holographic polymer/dispersed liquid crystal materials. Most of the components and devices are particularly adapted for use in wavelength division multiplexing (WDM) systems and in particular for use in switchable add/drop filtering (SADF) and wavelength selective crossconnect. Attenuators, outcouplers and a variety of other devices are also provided.
1. A method of fabricating an integrated optical network having a plurality of nodes, with at least one ESBG formed at each of said nodes including:
forming selected optical waveguides in a substrate, at least selected ones of said waveguides passing through selected ones of said nodes;
forming an ESBG with electrodes at each node; and
covering the waveguides and ESBGs
wherein said forming an ESBG step includes forming an electrode film and a H-PDLC film at each node, and exposing the H-PDLC film at each node to form an ESBG grating thereon.
2. A method as claimed in claim 1 wherein said covering step includes forming a second electrode film on a cover plate at each node; and covering the waveguides/H-PDLC films with said cover plate, each electrode on the coverplate overlying the H-PDLC film for the corresponding node.
3. A method as claimed in claim 1 wherein said exposing step includes one of (a) exposing each H-F DLC film with two interfering light beams of suitable wavelength, the beams being as a selected angle to each other; (b) exposing all of the films simultaneously through a suitable binary phase mask; and (c) exposing each of the films through a suitable mask.
4. A method as claimed in claim 1 wherein said forming waveguides step includes forming selected optical waveguides in a first substrate and in a second substrate, which substrates are mounted adjacent each other during said covering step 3, the waveguides on the two substrates intersecting at at least selected nodes.
5. A method as claimed in claim 4 wherein a H-PDLC film with ESBG gratings formed therein at said nodes is one of (a) formed on one of said substrates, and (b) independently formed and mounted between said substrates.
6. A method as claimed in claim 4 said forming electrode film step includes forming an electrode on each substrate on a waveguide at each node.
7. An integrated optical network having N guided wave optical inputs, and M guidewave optical outputs, said network including:
an optical waveguide connected to each input and to each output, said weveguides intersecting at nodes; and
an ESBG switch component at each node which is operative to either pass an optical signal on one waveguide intersecting at the node on the one waveguide or to transfer at least a portion of such optical signal to the other waveguide intersecting the node, depending on the state of the ESBG;
wherein all of said waveguides have substantially the same index n, and wherein the ESBG switch component at each node includes an ESBG having a grating with an index contrast n in optical contact with each waveguide, and at least one waveguide interconnecting the ESBGs, said waveguide having an index n 2 , where n 1−n 2 ≧Δn.