Optical switch with connection verification
First Claim
1. A switch for optical signals, comprising:
- a plurality of wavelength division demultiplexers (WDDs), each having an input port and a plurality of output ports;
a plurality of wavelength division multiplexers (WDMs), each having an output port and a plurality of input ports;
an optical switching core having a plurality of input ports at which optical signals enter said core and a plurality of output ports at which optical signals exit said core, a subset of the input ports of said core being connected to the output ports of said WDDs and a subset of the output ports of said core being connected to the input ports of said WDMs, said core being capable of establishing photonic connections between said subset of its input ports and said subset of its output ports in response to an indication of desired connections;
a plurality of optical intensity controllers, each connected to the input port of a corresponding one of said WDDs and adapted to vary the intensity of an input multi-carrier optical signal entering the input port of said corresponding one of said WDDs;
a plurality of optical splitters, each connected to the output port of a corresponding one of said WDMs and adapted to tap a fraction of the intensity of an output multi-carrier optical signal exiting the output port of said corresponding one of said WDMs; and
a connection verification unit connected to said optical intensity controllers and to said optical splitters, said connection verification unit being operable to;
(a) control said optical intensity controllers so as to cause a test signal to be applied to at least one of the input multi-carrier optical signals;
(b) determine, on the basis of at least one of the desired connections and for at least one of the signals exiting said subset of the output ports of said core, which test signal is expected to appear in said at least one of the signals exiting said subset of the output ports of said core;
(c) process the output multi-carrier optical signals tapped by said optical splitters in order to detect which test signal, if any, appears in said at least one of the signals exiting said subset of the output ports of said core; and
(d) compare the detected and expected test signals, thereby determining whether said at least one of the desired connections has been correctly established by said core.
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Abstract
An optical switch is equipped with a set of optical intensity controllers at its input, each intensity controller being driven to vary a corresponding WDM input traffic signal with a low power test signal. The switch is also equipped with optical splitters at its output and a path integrity analyzer connected to the splitters and to the intensity controllers. The path integrity analyzer generates or controls generation of the test signals applied by the intensity controllers. The path integrity analyzer also receives the tapped portions of the WDM output signals and separates them into their single-carrier components in order to recover a set of switched single-carrier optical signals. The path integrity analyzer is further provided with test signal detectors used to detect the presence of a test signal in each recovered switched single-carrier optical signal. The path integrity analyzer thus ascertains the integrity of the connection involving each switched single-carrier optical signal by comparing detected test signals to expected test signals that are derived from a connection map.
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Citations
33 Claims
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1. A switch for optical signals, comprising:
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a plurality of wavelength division demultiplexers (WDDs), each having an input port and a plurality of output ports;
a plurality of wavelength division multiplexers (WDMs), each having an output port and a plurality of input ports;
an optical switching core having a plurality of input ports at which optical signals enter said core and a plurality of output ports at which optical signals exit said core, a subset of the input ports of said core being connected to the output ports of said WDDs and a subset of the output ports of said core being connected to the input ports of said WDMs, said core being capable of establishing photonic connections between said subset of its input ports and said subset of its output ports in response to an indication of desired connections;
a plurality of optical intensity controllers, each connected to the input port of a corresponding one of said WDDs and adapted to vary the intensity of an input multi-carrier optical signal entering the input port of said corresponding one of said WDDs;
a plurality of optical splitters, each connected to the output port of a corresponding one of said WDMs and adapted to tap a fraction of the intensity of an output multi-carrier optical signal exiting the output port of said corresponding one of said WDMs; and
a connection verification unit connected to said optical intensity controllers and to said optical splitters, said connection verification unit being operable to;
(a) control said optical intensity controllers so as to cause a test signal to be applied to at least one of the input multi-carrier optical signals;
(b) determine, on the basis of at least one of the desired connections and for at least one of the signals exiting said subset of the output ports of said core, which test signal is expected to appear in said at least one of the signals exiting said subset of the output ports of said core;
(c) process the output multi-carrier optical signals tapped by said optical splitters in order to detect which test signal, if any, appears in said at least one of the signals exiting said subset of the output ports of said core; and
(d) compare the detected and expected test signals, thereby determining whether said at least one of the desired connections has been correctly established by said core. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A system for use with a switch for optical signals, the switch having a plurality of wavelength division demultiplexers (WDDs), each having an input port and a plurality of output ports;
- a plurality of wavelength division multiplexers (WDMs), each having an output port and a plurality of input ports; and
an optical switching core having a plurality of input ports at which optical signals enter the core and a plurality of output ports at which optical signals exit the core, wherein a subset of the input ports of the core is connected to the output ports of the WDDs and wherein a subset of the output ports of the core is connected to the input ports of the WDMs, the core being capable of establishing photonic connections between the subset of its input ports and the subset of its output ports in response to an indication of desired connections, the system comprising;a plurality of optical intensity controllers, each connectable to the input port of a corresponding one of the WDDs and adapted to vary the intensity of an input multi-carrier optical signal entering the input port of the corresponding one of the WDDs;
a plurality of optical splitters, each connectable to the output port of a corresponding one of the WDMs and adapted to tap a fraction of the optical intensity of an output multi-carrier optical signal exiting the output port of the corresponding one of the WDMs; and
a connection verification unit connected to said optical intensity controllers and to said optical splitters and being operable to;
(a) control said optical intensity controllers so as to cause a test signal to be applied to at least one of the input multi-carrier optical signals;
(b) determine, on the basis of at least one of the desired connections and for at least one of the signals exiting said subset of the output ports of said core, which test signal is expected to appear in said at least one of the signals exiting said subset of the output ports of said core;
(c) process the output multi-carrier optical signals tapped by said optical splitters in order to detect which test signal, if any, appears in said at least one of the signals exiting said subset of the output ports of said core; and
(d) compare the detected and expected test signals, thereby determining whether said at least one of the desired connections has been correctly established by said core.
- a plurality of wavelength division multiplexers (WDMs), each having an output port and a plurality of input ports; and
Specification