US 4,934,775 AGranted

Optical space switches using cascaded coupled-waveguide optical gate arrays

AssigneeGTE Laboratories Incorporated

InventorKwang T. Koai

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Abstract

An optical space switch architecture is constructed from electro-optical gate arrays each comprised of a plurality of ultra-high-extinction optical intensity modulators which are in turn fabricated from cascaded directional waveguide coupler sections. Input optical signals are processed by 1-to-N passive splitter circuits for providing interim optical signals which are routed to the optical gtate arrays. Each interim signal is processed by an optical modulator and emerges, depending upon the activation of the particular gate, in either an ON or OFF state. The optical signals emerging from the gate arrays are routed to N-to-1 passive combiner circuits according to a connectivity configuration whereupon the incoming signals are combined before appearing at the output ports of the combiner circuits. Optical amplifiers are incorporated into the splitter and combiner circuits if power compensation is required. The point-to-multipoint connectivity configuration allows each input optical signal to be distributed to all of the output ports if so desired. The switching connections for establishing the desired distribution of the input optical signals among the output ports are implemented by turning ON or OFF the appropriate electro-optic gates in the gate array.

Claims18

Dependent claims

A broadband optical space-division switching architecture for selectively or fully distributing a plurality of ON/OFF input optical signals among a plurality of output ports, comprising:

a plurality of passive splitter circuits each evenly dividing an input optical signal into a plurality of interim optical signals;
a set of high-extinction electro-optic gate arrays each comprising a plurality of optical intensity modulators each of which consists of high-extinction cascaded directional waveguide coupler sections, each of said modulators receiving one of the plurality of interim optical signals from said splitter circuits and processing said one interim signal in accordance with a current operational state of said modulator;
each of said optical intensity modulators normally operating in an OFF state wherein
the directional waveguide coupler sections of each optical modulator are cascaded together on a crystal substrate to form a bar-type modulator structure which provides a direct optical connection between the associated first section and the associated last section, and wherein
each of said waveguide coupler sections includes a primary waveguide and a corresponding secondary waveguide forming a coupling region therebetween wherein each secondary waveguide has a bend structure so that an optical signal coupled into the secondary waveguide from said associated primary waveguide is guided out of said modulator, and each primary waveguide is contiguous with the primary waveguide in a next section so that the uncoupled signal propagates into the primary waveguide of said next section;
a first connection means providing said interim optical signals with an optical path connection between said splitter circuits and the optical modulators in said gate arrays;
a plurality of passive combiner circuits each having a single output port and constructed in an inverse configuration to that of said splitter circuits;
second connection means coupling said optical modulators to said passive combiner circuits whereby the ON/OFF optical signals from said gate arrays propagate to said combiner circuits;
each of said combiner circuits combining the incoming optical signals routed thereto by said second connection means into a single output signal appearing at the respective single output port of said combiner circuit;
and
means for establishing a desired switching connectivity between the input ports of said splitter circuits and the output ports of said combiner circuits by activating the appropriate operational state of each of said optical intensity modulators whereby the input optical signals are routed to their respective output ports in accordance with said desired connectivity.

8 more elements

A broadband optical space-division switching architecture for selectively or fully distributing a plurality of ON/OFF input optical signals among a plurality of output ports, comprising:

a plurality of passive splitter circuits each evenly dividing an input optical signal into a plurality of interim optical signals;
a set of high-extinction electro-optic gate arrays each comprising a plurality of optical intensity modulators each of which consists of high-extinction cascaded directional waveguide coupler sections, each of said modulators receiving one of the plurality of interim optical signals from said splitter circuits and processing said one interim optical signal in accordance with a current operational state of said modulator;
each of said optical intensity modulators normally operating in an ON state wherein
the directional waveguide coupler sections of each optical modulator are cascaded together on a crystal substrate to form a cross-type modulator structure, and wherein
each of said waveguide coupler sections includes a primary waveguide having a bend structure and a corresponding secondary waveguide together forming a coupling region therebetween wherein each secondary waveguide is contiguous with the primary waveguide in a next section such that an optical signal coupled into the secondary waveguide of one section from said corresponding primary waveguide propagates into the primary waveguide of said next section, and the remaining uncoupled signal present in the primary waveguide of said one section propagates out of said modulator through said respective waveguide bend;
a first connection means providing said interim optical signals with an optical path connection between said splitter circuits and the optical modulators in said gate arrays;
a plurality of passive combiner circuits each having a single output port and constructed in an inverse configuration to that of said splitter circuits;
second connection means coupling said optical modulators to said passive combiner circuits whereby the optical signals from said gate arrays propagate to said combiner circuits;
each of said combiner circuits combining the incoming optical signals routed thereto by said second connection means into a single output signal appearing at the respective single output port of said combiner circuit;
and
means for establishing a desired switching connectivity between the input ports of said splitter circuits and the output ports of said combiner circuits by activating the appropriate operational state of each of said optical intensity modulators whereby the input signals are routed to their respective output ports in accordance with said desired connectivity.

8 more elements

Dependencies are inferred from the claim text.