Abstract: A method and apparatus for performing a path based quality check for a specified bit rate in a wavelength division multiplexing optical network is described. According to one embodiment of the invention, a method selects from a database one of the available paths as a currently selected path. The database stores a representation of the available paths from an access node of the optical network to other access nodes of the optical network. The method further determines a cumulative noise, cumulative chromatic dispersion, and a maximum allowable chromatic dispersion for the currently selected path. In addition, the method determines whether the currently selected path passes the path based quality check based on whether the cumulative noise is less than the maximum allowable noise at a specific bit rate and whether the chromatic dispersion is less than the maximum allowable chromatic dispersion at the specified bit rate.

Abstract: A method and apparatus for performing a path based quality check for a specified bit rate in a wavelength division multiplexing optical network is described. According to one embodiment of the invention, a method selects from a database one of the available paths as a currently selected path. The database stores a representation of the available paths from an access node of the optical network to other access nodes of the optical network. The method further determines a cumulative noise, cumulative chromatic dispersion, and a maximum allowable chromatic dispersion for the currently selected path. In addition, the method determines whether the currently selected path passes the path based quality check based on whether the cumulative noise is less than the maximum allowable noise at a specific bit rate and whether the chromatic dispersion is less than the maximum allowable chromatic dispersion at the specified bit rate.

Abstract: A method and apparatus for implementing optical network quality using bit error rate and chromatic dispersion. According to one embodiment of the invention, a method includes the provision of quality of service in a wavelength division multiplexing optical network that supports a plurality of bit rates. As part of this method, the cumulative noise and cumulative chromatic dispersion for each available path as a whole is determined, where an available path is a series of two or more nodes each connected by an optical link on which a set of wavelengths is available for establishing a lightpath. In addition, different grades of path quality are distinguished based on bit error rate (BER), where BER is based on cumulative noise and bit rate. Furthermore, a minimum path quality is required based on chromatic dispersion decibel penalty, where chromatic dispersion decibel penalty is based on cumulative chromatic dispersion and bit rate.

Abstract: Modular WSS-based Communications system with colorless and network-port transparent add/drop interfaces is described herein. According to certain aspects of the invention, equipment architecture is provided that enables a linear, ring, and mesh optical network. The embodiments of the invention are primarily on how to add and drop signals at a node of the network. The embodiments of the invention are based on the use a wavelength selective switch (WSS), which is an emerging component technology. Other methods and apparatuses are also described.

Abstract: According to one aspect of the invention, an optical network including multiple optical network devices, or nodes, is provided. At each node, an optical performance monitor analyzes dispersion while a dispersion compensation module reduces the amount of dispersion in the signals. Information about the dispersion and the amount of compensation performed by the dispersion compensation module is generated by the optical performance monitor and stored in a memory. If the bit error rate of a particular path between nodes becomes too high, a new path is used. A monitoring computer then accesses the information about the dispersion stored in at least one node of the old path. The information allows a user to determine where along the path the greatest amount of dispersion is occurring.

Abstract: A method and an apparatus to provide optical equipment protection have been disclosed. In one embodiment, the method includes splitting an incoming optical signal into a first and a second optical signals, sending the first and the second optical signals to a first and a second equipments in an optical network node, respectively, the second equipment being a protection module for the first equipment, monitoring a first and a second outgoing optical signals from the first and second equipments, and declaring a failure of the optical network node if only one of the first and the second outgoing optical signals has failed. Other embodiments have been claimed and described.

Abstract: A method and apparatus for implementing optical network quality using bit error rate and chromatic dispersion. According to one embodiment of the invention, a method includes the provision of quality of service in a wavelength division multiplexing optical network that supports a plurality of bit rates. As part of this method, the cumulative noise and cumulative chromatic dispersion for each available path as a whole is determined, where an available path is a series of two or more nodes each connected by an optical link on which a set of wavelengths is available for establishing a lightpath. In addition, different grades of path quality are distinguished based on bit error rate (BER), where BER is based on cumulative noise and bit rate. Furthermore, a minimum path quality is required based on chromatic dispersion decibel penalty, where chromatic dispersion decibel penalty is based on cumulative chromatic dispersion and bit rate.

Abstract: A method and apparatus for an electrically switched optically protecting network device is described. One embodiment of the invention established pairs of optical circuits between different electrically switched optically protecting network devices acting as access nodes of an optically switched network. The network device communicates different add/drop traffic flows between externally facing ports of different electrically switched optically protecting network devices by transmitting over the optical circuit. In addition, the network device optically switches optical circuits for which the network device is an intermediate node and electrically switches packets between different ones of the network devices' externally facing ports and those of the optical circuits for which the network device is an end node. Furthermore, the network device protects the communication of traffic flows across the optical network by controlling the packet electrical switching to the pairs of optical circuits.

Abstract: Modular WSS-based Communications system with colorless and network-port transparent add/drop interfaces is described herein. According to certain aspects of the invention, equipment architecture is provided that enables a linear, ring, and mesh optical network. The embodiments of the invention are primarily on how to add and drop signals at a node of the network. The embodiments of the invention are based on the use a wavelength selective switch (WSS), which is an emerging component technology. Other methods and apparatuses are also described.

Abstract: A method and an apparatus to provide optical equipment protection have been disclosed. In one embodiment, the method includes splitting an incoming optical signal into a first and a second optical signals, sending the first and the second optical signals to a first and a second equipments in an optical network node, respectively, the second equipment being a protection module for the first equipment, monitoring a first and a second outgoing optical signals from the first and second equipments, and declaring a failure of the optical network node if only one of the first and the second outgoing optical signals has failed. Other embodiments have been claimed and described.

Abstract: A method and an apparatus to provide optical equipment protection have been disclosed. In one embodiment, the method includes sending a first optical signal from an optical transceiver to a wavelength switch module (WSM), checking a second optical signal received by the optical transceiver after sending the first optical signal, and determining whether the second optical signal corresponds to the first optical signal. Other embodiments have been claimed and described.

Abstract: A method for routing optical signals within an optical switch matrix is described herein. In one embodiment, exemplary routing within the optical switch matrix includes, but is not limited to, providing a plurality of switching nodes and a plurality of intermediate wavelengths. Furthermore, any one of a plurality of input waveguides is coupled with any one of a plurality of output waveguides, using one or more of the switching nodes and the intermediate waveguides. In addition, a switching node couples the respective input waveguide and the respective output waveguide. The switching node includes a first switch coupling the respective input waveguide to an intermediate waveguide and a second switch coupling the intermediate waveguide to the respective output waveguide.

Abstract: An optical switch matrix is described herein. In one embodiment, an exemplary optical switch matrix includes, but is not limited to, multiple input waveguides, multiple output waveguides, for each of the input waveguides and each of the output waveguides, a switching node coupling the respective input waveguide and the respective output waveguide. The switching node includes a first switch coupling the respective input waveguide to an intermediate waveguide and a second switch coupling the intermediate waveguide to the respective output waveguide. The second switch is an X switch having first and second input ports and first and second output ports, the first input port receiving the intermediate waveguide and the first output port coupling to the respective output waveguide. Other methods and apparatuses are also described.

Abstract: A method and an apparatus to provide optical equipment protection have been disclosed. In one embodiment, the method includes diverting a predetermined portion of each of a plurality of optical signals to a plurality of photonic detectors within a first optical network node, and detecting the plurality of signals using the plurality of photonic detectors, each of the plurality of photonic detectors being designated to detect one of the plurality of optical signals. Other embodiments have been claimed and described.

Abstract: An optical backplane system is described herein. In one embodiment, an exemplary system includes a backplane to interconnect multiple optical modules, multiple fiber interface modules (FIMs) having a back end inserted into multiple slots of the backplane respectively, each FIM having a front end to receive an incoming fiber carrying incoming optical signals and an outgoing fiber carrying outgoing optical signals from and to an optical network. The back end of the FIM extends the incoming and outgoing fibers to at least one of the multiple optical modules mounted via the backplane without significantly processing of the incoming and outgoing optical signals. Each of the fibers is capable of carrying multiple wavelengths of optical signals. Other methods and apparatuses are also described.

Abstract: A method of transmitting broadband video services from a broadband digital signal source which includes forming the digital signal from said source into a plurality of channels of digital signals and modulating a plurality of carrier signals with respective channels of the digital signals. The resultant modulated channels are multiplexed to form a combined signal which is then used to modulate light from a laser light source. The modulated light signal is transmitted along a light fibre to a local distribution box where it is converted to electrical signals and broadcast to a number of subscriber set top terminals, Each set top terminal detects the modulated signal of a channel pre-assigned to that set top terminal. User control information is also received by that set top terminal and transmitted to the central office.

Abstract: A known electro-optic has a semiconductor laser, a temperature sensor for controlling an electrically operated cooler, and an optical fiber end portion anchored close to the laser to receive light from it. Usually the fiber is anchored by a mass of cured epoxy. This invention proposes anchoring the fiber in a mass of fusible alloy which is melted and solidified using a Peltier effect device which is driven with one polarity current to function as a heater and with a reverse polarity current to function as a cooler. Once the package is complete and the laser is operating, the temperature sensor together with the Peltier effect device functioning as a cooler are used to cool the laser.

Abstract: In a method and apparatus for bonding a semiconductor laser chip to a heatsink and testing the bond obtained, temperature in the bonding operation is regulated by passing a small fixed current through the forward biased laser and monitoring corresponding change in voltage caused by alteration of the laser pn junction temperature. Current is passed to the laser through a floating contact consisting of a conducting vacuum pick-up pressed against the laser top surface. Bond integrity is subsequently tested at low temperature by passing a dc current greater than a threshold current through the laser and measuring the resulting light output and then passing a pulsed current with identical peak current level and again measuring light output. The difference in light output is a function of the bond thermal resistance.

Abstract: In a fabricating a III-V compound, for example, GaAs, having a layered structure a first layer is grown on a planar substrate by a vapor deposition process adapted to produce differential growth while a subsequent layer is grown by a deposition process which restores planarity. In this way a uniformly thick combination layer is produced with a non-planar junction between its composite layers. Particularly in the fabrication of channelled substrate double heterostructure lasers, a channelled blocking layer is grown by organo-metallic pyrolysis (OMP) and a subsequent confining layer is grown using liquid phase epitaxy (LPE). The OMP process produces a channel with flanking shoulder portions which permit LPE growth of a very thin confining layer immediately above the shoulder portions thereby improving linearity of the device.

Abstract: Semiconductor lasers exhibit transient relaxation oscillation on start-up and specific lasers often exhibit sustained spontaneous pulsations caused probably by crystalline defects. These fluctuations are suppressed in a laser having an integrally formed light emitting diode (LED) which generates spontaneous light which is coupled into the laser by virtue of the close proximity of the laser and the light emitting diode.