Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.

Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A method and apparatus are presented for implementing maintenance signaling in an optical data network, said method comprising the use of a finite set of optical symbols to distinguish between different classes of failures. The method is format and bit rate transparent, and a network element does not need to read bits to interpret a signaling message. Faults protected within the network are distinguished from faults originating outside the network, and power glitches are filtered out of incoming alarm signals originating outside the network.

Abstract: A robust nonblocking switch architecture is presented, in the first and final stages made of switch modules which have extra, unallocated, input and output ports beyond those necessary to render the switch architecture nonblocking. Each middle stage has an extra switch module, affording it spare unallocated ports as well. A method of isolating a fault is also presented, given the robust switching architecture. Operating on each stage one at a time, the switching architecture is reconnected so as to bypass either the input, the output, or both the input and the output ports of the switch module in such stage impacted in the faulted signal path. Such method allows the isolation of the faulty switch module, and can be done automatically, with either external apparatus, or integrated fault isolation equipment.

Abstract: Method and apparatus are presented which define generic cross-connect primitives that enable the implementation of 1+1 protection in a mesh configured optical network. Such primitives are capable of supporting both 1+1 network protection as well as 1+1 client/access protection, or both. Further, the invention supports multicast applications at no additional architectural cost.

Abstract: Method and apparatus are presented for the generation and detection of maintenance signals in an optical data network. The maintenance signals are such that they can be read both by high bit-rate and low bit-rate receivers. Detection of the maintenance signals occurs in two stages. In a low bit-rate first stage each nodal input port is sampled in a round robin fashion to detect the presence of a maintenance signal. In a high bit-rate second stage the maintenance signal is verified and read by a high speed receiver, along with other high bit-rate information transmitted with it. One second stage high speed receiver is shared among M input channels for cost and circuit efficiency.

Abstract: A method and apparatus for providing signaling for disjoint shared protection in a data network are presented. In a preferred embodiment the method utilizes one or more of the same set of finite optical signals used for maintenance purposes in the network, which can be recognized without regard to bit rate or format. Nodes that share a failed link send an alarm signal that reaches the initiator and terminator node, whereupon the initiator node sends a signal that activates a protection lightpath. When the signal sent by the initiator node arrives at the terminator node, it sends back an acknowledge signal. If the acknowledge signal is not received within a certain time protection is voided. Contention for shared protection resources is resolved via a priority scheme.

Abstract: A method and apparatus for a tunable optical spectrum analyzer that can measure the optical spectrum of a demultiplexed DWDM signal are presented. The signal level and Optical Signal to Noise Ratio (OSNR) of an individual channel of the DWDM signal can be obtained from the measured optical spectrum. The device employs a rapid tuning and detection technique to obtain the optical spectrum of the incoming signal. In a preferred embodiment the apparatus is fabricated on a single chip resulting in a compact measurement device. Using the device of the preferred embodiment, single channel OSNR can be determined in as small a time interval as approximately 225 microseconds. Using an array of these devices an entire DWDM mixed signal can be monitored as to OP and OSNR in the same time interval.

Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.

Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.

Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.

Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.

Abstract: A novel solution to fast network restoration is provided. In a network node, dedicated hardware elements are utilized to implement restoration, and these elements are linked via a specialized high speed bus. Moreover, the incoming and outgoing optical signals to each input/output port are continually monitored and their status communicated to such dedicated hardware via the high-speed bus. This provides a complete snapshot in virtually real time of the state of each input port on the node, and the switch map specifying the inter portal connections, to the dedicated control and restoration hardware. The specialized hardware detects trouble conditions and reconfigures the switching fabric. The invention enables a very fast and efficient control loop between the I/O ports, switch fabrics, and controllers.

Abstract: A method and system for AO3R functionality is presented. The system includes an AO2R device followed by an AOCR clock recovery module and an AOR retiming device. The AOR retiming device takes as input a recovered clock signal extracted from the output of the AO2R by the AOCR clock recovery module. The output is the recovered clock signal gated by the regenerated and reshaped input signal, and a monitor circuit is used to set the optimum operations of the retiming device. In a first embodiment the output of the AOR retiming device is fed to an AOC code and wavelength conversion output stage, which returns the signal to the NRZ coding, on a service wavelength converted to match the fixed wavelength connection with the DWDM transmission system. In a second embodiment the code conversion is incorporated into the AOR retiming device, and wavelength conversion is accomplished in the AOCR clock recovery device.

Abstract: The present invention provides an optical signal quality selection system for optimizing the quality of information transmission. The system splits an incoming optical signal into two equal signals. The split signals are evaluated in optical performance monitors, transmitting an electrical output message to a signal selector relating to the quality of the respective signal. A second electrical message is sent from the optical performance generator to an alarm indicator signal generator, which sends an optical signal to the signal selector to drop the one of the split signals and transmit the non-dropped split signal. An unequipped optical signal from an optical idle signal generator is triggered if no active optical signal is being transmitted.

Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.