Abstract: An automated fiber optic patch-panel/cross-connect system comprised of a stacked arrangement of multiple replaceable modules, including a first multiplicity of fiber modules, each with a second multiplicity of reconfigurable internal fiber connectors; a common robot module shared among fiber modules, wherein any connector within a fiber module in the system can be moved to any other connector of any other fiber module in the system; a power management module that distributes electrical power to the fiber modules and the robot module; and a server module that generates commands that are placed on communication bus to activate robot and fiber modules. The modules are physically separated and spatially arranged to be serviced replaced without interrupting fiber connections previously established in the system.

Abstract: An arrayed waveguide for a photonic integrated circuit has a single optical path with serially connected delay lines. Different delayed optical paths or channels are periodically split off from the serially connected optical delay path. This has the net result of requiring much less space on-chip for comparable optical path differences with high spectral resolution.

Abstract: A wavelength conversion device disclosed adopts a drive gear and driven gear as a main transmission structure, and disposes optical fiber plugs at a center of the driven gear. When a central shaft of the driven gear is unmovable, the rotation of the drive gear will drive the driven gear to rotate, and the rotation of driven gear will drive the optical fiber insertion rod to move up and down, thereby completing an insertion-extraction operation of the optical fiber insertion rod. When the central shaft of the driven gear is movable, i.e., when the optical fiber plugging rod is completely above the baseplate, the driven gear is locked with the optical fiber plug and thus they both cannot be rotated about their own axis, the driven gear will drive the fiber displacement plate to rotate along the drive gear under the action of the drive gear, thereby realizing the rotational translation of the optical fiber plugs, and reaching the switching wavelengths of laser at the optical fiber output interface.

Abstract: The present disclosure relates to a method including arranging multiple optical fibers between a die and a lid, wherein the die is bent and comprises multiple grooves, each optical fiber in or close to a separate groove; bonding the lid to the die to hold the multiple optical fibers in place in the multiple grooves, wherein the bonding comprises applying a bonding force non-uniformly across the lid to conform the lid to the bent die. A corresponding system is also disclosed herein.

Abstract: A photonic integrated chip is configured as a transmitter-receiver chip. The photonic integrated chip includes a light emitter, a light detector, a multi-mode interference coupler, and a mode-filed adapter. The light emitted by the light emitter is guided to a core layer formed below the multi-mode interference coupler, and further to the mode-filed adapter for transmission of light to an optical fiber coupled with the photonic integrated chip. Similarly, light received by the mode-filed adapter from the optical fiber propagates to the core layer, and is guided by the multi-mode interference coupler into the light detector. The photonic integrated chip is utilized to realize a single-unit transmitter-receiver module for a fiber optic gyroscope circuit based on monolithic integration of photonics components via wafer fabrication on a substrate. The photonic integrated chip has a low fabrication cost, low size, and is robust.

Abstract: The disclosure provides a dispersion management method and apparatus based on non-periodic spectral phase jumps. Precise dispersion is provided by virtue of non-periodic spectral phase jumps, the dispersion can be tuned freely with engineering of the phase jump. A device based on non-periodic spectral phase jump also has a wide working bandwidth and could promote the development of ultrafast optics. The method includes: spatially separating a light pulse with different frequency components, and meanwhile, making the light pulse with the different frequency components propagate in parallel; enabling the light pulse with the different frequency components and propagating in parallel to be incident on a non-periodic phase jump device to obtain non-periodic spectral phase jumps, forming a phase grating effect to obtain two ±1-order diffracted pulses having opposite group delays, and introducing frequency dependent relative delay for the different spectral components in the two diffracted pulses.

Abstract: The present disclosure provides an improved method of parking a microelectromechanical system (MEMS) mirror in an array of MEMS mirrors to protect against single high voltage channel failures in a driver. Two separate voltages are applied to each MEMS mirror to move and park the mirror out of a camera sensor field of view in a servo system. For example, a first voltage may be applied in a positive X direction and a second voltage may be applied in a positive Y direction which will move the mirror in a diagonal direction. If one of the high voltage channels fail, the mirror will still be parked and outside of the camera sensor field of view. If a high voltage channel fails, the servo system can park a mirror affected by the failure in an opposite corner. Moreover, if 2-axis parking is not feasible, the mirror can use single-voltage parking.

Abstract: A system includes a memory and at least one processing device operatively coupled to the memory to facilitate an etch recipe development process by performing a number of operations. The operations include receiving a request to initiate an iteration of an etch process using an etch recipe to etch a plurality of materials each located at a respective one of a plurality of reflectometry measurement points, obtaining material thickness data for each of the plurality of materials resulting from the iteration of the etch process, and determining one or more etch parameters based on the material thickness data.

Abstract: A method for fabrication a multifiber cable assembly is provided. The method includes selecting a plurality of optical fibers that each have a respective cladding diameter, determining a maximum fiber core position error for the plurality of optical fibers in a plurality of configurations, and determining a desired order of the plurality of optical fibers that minimizes the maximum fiber position total error.

Abstract: A pair of acousto-optic deflectors (AODs) is used to steer a pair of laser beams to address individual atoms of an array of atoms so that the beams can conditionally induce a 2-photon transition between the atom's quantum energy levels. The first beam is deflected into a +1 diffraction order, resulting in an AOD output beam with a frequency greater than that of the respective AOD input beam. The second beam is deflected into a ?1 diffraction order so that the AOD output beam has a frequency less than that of the respective AOD input beam. The equal and opposite frequency changes compensate it other so that the sum of the output frequencies remains constant.

Abstract: A network system for a data center is described in which a switch fabric provides interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers. The access nodes may be arranged within access node groups, and permutation devices may be used within the access node groups to spray packets across the access node groups prior to injection within the switch fabric, thereby increasing the fanout and scalability of the network system.

Abstract: Time delay devices for producing tunable time delays in optical signals. Cascades of the time delay devices can be used for beam steering in phased-array antennas. The time delay may be produced by selecting a time delay between an input and output of the time delay device from any of the time delay obtained by all four-port switches of the time delay device being in an OFF state and time delays obtainable by switching any one of the four-port switches to an ON state; and producing the selected time delay between the input and output of the time delay device by performing any of avoiding an application of an electrical control signal to any of electro-optic switch elements of the time delay device and applying the electrical control signal to one of the electro-optic switch elements that corresponds to a four-port coupler corresponding to the selected time delay.

Abstract: A connection structure for optical waveguide chips includes a silica-based PLC in which grooves are formed, spacer steel balls fitted in the grooves, and silica-based PLCs in which grooves into which the spacer steel balls to be fitted are formed, the silica-based PLCs being mounted on the silica-based PLC by being supported by the spacer steel balls. A conductor wire formed in the silica-based PLC and a conductor wire formed in the silica-based PLC are electrically connected to each other by a conductor film formed in the groove, the spacer steel balls and a conductor film formed in the groove.

Abstract: Nonreciprocal optical transmission devices and optical apparatuses including the nonreciprocal optical transmission devices are provided. A nonreciprocal optical transmission device includes an optical input portion, an optical output portion, and an intermediate connecting portion interposed between the optical input portion and the optical output portion, and comprising optical waveguides. A complex refractive index of any one or any combination of the optical waveguides changes between the optical input portion and the optical output portion, and a transmission direction of light through the nonreciprocal optical transmission device is controlled by a change in the complex refractive index.

Abstract: Methods, systems, computer-readable media, and apparatuses for obtaining blood pressure measurements are presented. The blood pressure measurements may be obtained by determining a pulse-transit time (PTT) as a function of a photoplethysmography (PPG) measurement and electrocardiogram (ECG) measurement. A mobile device includes outer body sized to be portable for a user of the mobile device. The mobile device also includes a plurality of light emitting components distributed along at least one portion of the mobile device and a plurality of light collecting components configured to measure reflected light from the plurality of light emitting components reflected off of blood vessels within the user. The light emitting and light collecting components are distributed along the at least one portion of the mobile device. The mobile device may also include a light guide configured to direct light emitted by the at least one light emitting component toward blood vessels with the user.

Abstract: Methods, systems, computer-readable media, and apparatuses for obtaining blood pressure measurements are presented. The blood pressure measurements may be obtained by determining a pulse-transit time (PTT) as a function of a photoplethysmography (PPG) measurement and electrocardiogram (ECG) measurement. A mobile device includes outer body sized to be portable for a user of the mobile device. The mobile device also includes a plurality of light emitting components distributed along at least one portion of the mobile device and a plurality of light collecting components configured to measure reflected light from the plurality of light emitting components reflected off of blood vessels within the user. The light emitting and light collecting components are distributed along the at least one portion of the mobile device. The mobile device may also include a light guide configured to direct light emitted by the at least one light emitting component toward blood vessels with the user.

Abstract: A wet plant manager (WPM) platform is disclosed in accordance with an embodiment of the present disclosure, and supports management of Smart Undersea Network Elements (SUNEs) by providing an abstracted view of the same to higher level network management functions within an optical communication system. The optical communication system can include an optical cable system extending between two or more cable landing stations (CLSs). Each CLS may execute a respective instance of a WPM platform service, with the collective WPM platform performing self-coordination such that only one instance of a WPM service is “active” at any given time. The active WPM service supports a plurality of network topologies architected around SUNEs and “bridges” them such that requests to communicate with a particular SUNE get handled in a transparent manner without the requesters specific knowledge of which command/response (CR) telemetry path was utilized to satisfy the request.

Abstract: An optical switching system comprising a switching cell having first and second fixed-position bus waveguides and a moveable shunt waveguide is disclosed. The first bus waveguide includes an input and a first output. The second bus waveguide includes a second output. When the switching cell is in its unswitched state, the shunt waveguide is not optically coupled with either bus waveguide and a light signal can pass from the input to the first output while remaining in the first bus waveguide. When the switching cell is in its switched state, the shunt waveguide is optically coupled with both bus waveguides such that the light signal is coupled out of the first bus waveguide and into the second bus waveguide via the shunt waveguide. As a result, the light signal can pass from the input to the second output while bypassing the first input.

Abstract: The invention provides an electro-optically induced waveguide including: a waveguide layer stack having a core layer including an electro-optic material for guiding light waves; and a field generator for generating an electrical field in the core layer, wherein the field generator includes an electrode arrangement having a plurality of electrodes and a voltage supply arrangement for supplying at least two potentials to the electrode arrangement; wherein the field generator is configured to induce an electro-optic effect by the generated electrical field in a first cross sectional region of the core layer such that a propagation of transverse-electric polarized light waves is enabled in the first cross sectional region; wherein the field generator is configured to induce an electro-optic effect by the generated electrical field in a second cross sectional region of the core layer such that a propagation of transverse-magnetic polarized light waves is enabled in the second cross sectional region; and wherein

Abstract: An optical path system includes a first rectangular block that further includes multiple first fiber optic guides, arranged in a first configuration, into which are placed multiple first optical fibers, one fiber in each guide. The optical path system further includes a second rectangular block comprising multiple second fiber optic guides, arranged in a second configuration, into which are placed multiple second optical fibers, one fiber in each guide, wherein a first face of the second rectangular block abuts a first face of the first rectangular block and wherein the first block is movable relative to the second block. The optical path system also includes micro-position adjusting mechanisms configured to move the first block relative to the second block to align the multiple first optical fibers with the multiple second optical fibers.

Abstract: A cartridge-type optical functional module achieves excellent optical coupling and may include an optical fiber-type module and/or a waveguide-type module. A cartridge-type optical functional module is provided that includes first and second optical fiber collimators, an optical functional object that has an optical fiber-type module or a waveguide-type module, and a base section. The optical functional object also includes a third collimator, and a first alignment mechanism for aligning the position of the third collimator in the optical functional object.

Abstract: A method and module for affecting controlled switching of optical signals having different modes of propagation, wherein the module being provided with at least two multi-mode ports MMPs and a plurality of single-mode ports SMPs, the method comprises: inputting at least one multimode optical signal to an MMP of said MMPs; inputting the single mode optical signals to the SMPs; performing mode processing of one or more of the single mode and multi mode optical signals within the switching module, controllably and selectively switching different optical signals inputted to different ports of the module, preferably based on received feedback related to quality information, thereby allowing switching between single mode ports, between multi-mode ports, and between single mode and multi mode ports.

Abstract: Embodiments of the present invention are directed to optoelectronic network switches. In one embodiment, an optoelectronic switch includes a set of roughly parallel input waveguides and a set of roughly parallel output waveguides positioned roughly perpendicular to the input waveguides. Each of the output waveguides crosses the set of input waveguides. The optoelectronic switch includes at least one switch element configured to switch one or more optical signals transmitted on one or more input waveguides onto one or more crossing output waveguides.

Abstract: An optical beam switch includes at least one input optical wave guide, multiple output optical wave guides and an optical switching element for selectively switching a light beam guided in the at least one input optical wave guide to one of the output optical wave guides, in which the switching element is between the at least one input optical waveguide and the multiple output optical waveguides. The optical switching element includes a beam propagation element and an optical focusing system, where the beam propagation element has two mutually opposed end faces and where either the beam propagation element or the optical focusing system can be deflected and/or twisted transversely to an optical axis. The at least one input optical wave guide is attached to a first end face of the beam propagation element, and the output optical wave guides are attached to a second end face.

Abstract: A circuit switched optical device includes a first array of intersecting hollow waveguides formed in a first plane of a substrate. A second array of intersecting hollow waveguides is formed in a second plane of the substrate, and the second plane is positioned parallel to the first plane. An optical element within the first array selectively redirects an optical signal from the first array to the second array.

Abstract: Telecommunications switches are presented, including expandable optical switches that allow for a switch of N inputs×M outputs to be expanded arbitrarily to a new number of N inputs and/or a new number of M outputs. Switches having internal switch blocks controlling signal bypass lines are also provided, with these switches being useful for the expandable switches.

Abstract: An optical switch system and the system includes a semi-transmissive semi-reflective module is configured to intercept, in a transmission manner, test light that is the same as the signal light with respect to the propagation path and output after being modulated by the optical output control module; the imaging module is configured to acquire the test light, generate corresponding initial optical path information and sampled optical path information in sequence, and transfer the initial optical path information and the sampled optical path information to the judging module in sequence; the judging module is configured to record the initial optical path information, and compare the sampled optical path information with the initial optical path information; and the control module is configured to control the optical output control module according to a comparison result.

Abstract: A system for measuring properties of a thin film coated glass having a light source, a spectrometer, at least one pair of probes, a first optical fiber switch and a second optical fiber switch. The pair of probes includes a first probe located on one side of a glass sheet and a second probe located on the opposite side of the glass sheet, directly across from the first probe. The first and second optical fiber switches are adapted to couple either probe to the light source and/or the spectrometer. Because the design of the system is optically symmetrical, calibration may be performed without the use of a reference material such as a tile or mirror. Each of the first and second probes has a first leg and a second leg that are separated from each other by a distance n so that angled reflections may be detected.

Abstract: A compact photonic time delay unit. The unit includes a plurality of compact optical delay elements, a plurality of delay bypass elements, with each delay bypass element being associated with a respective one of the compact optical delay elements, and a plurality of compact optical switches. Each of the compact optical switches is configured to controllably switch an optical signal through one of the compact optical delay elements or through the associated delay bypass element. In some aspects, the compact optical delay elements, delay bypass elements, and compact optical switches are disposed on a single electro-optical chip.

Abstract: An optical cross-connect apparatus includes: a plurality of switch units connected to each other via input ports and output ports; a storage unit to store a setting table in which output port information and corresponding input port information are associated together and registered for each optical signal such that the output port information identifies a specific output port, in the output ports, that outputs the optical signal and the input port information identifies a specific input port, in the input ports, that inputs the optical signal; a setting processor to set each switch unit in the plurality of switch units according to the setting table so as to set a wavelength for each optical signal that is input via the input ports or output via the output ports; and an update processor to update the content of the setting table in response to external input.

Abstract: A configurable optical communications system (100) for establishing point-to-point communications between multiple computer servers (160) coupled to a common midplane or backplane communications bus (132), wherein at least two of the servers include an optical input/output device (170) for sending and receiving an optical signal (112). The system further includes an optical communications pathway (140) that is configured to carry the optical signal, and at least two pivotable mirrors (150) located within the optical pathway and in-line with the optical input/output devices that are selectively orientated to direct the optical signal between the optical input/output devices to establish the point-to-point communication between the at least two servers.

Abstract: Disclosed is a three-wavelength optical multiplexer which is compact, and which multiplexes light having different wavelength incident to three single-mode optical fibers, particularly light of red, green, and blue at transmittance above a certain reference.

Abstract: A system for measuring properties of a thin film coated glass having a light source, a spectrometer, at least one pair of probes, a first optical fiber switch and a second optical fiber switch. The pair of probes includes a first probe located on one side of a glass sheet and a second probe located on the opposite side of the glass sheet, directly across from the first probe. The first and second optical fiber switches are adapted to couple either probe to the light source and/or the spectrometer. Because the design of the system is optically symmetrical, calibration may be performed without the use of a reference material such as a tile or mirror.

Abstract: An N×N switching apparatus for optical components is provided. A switching apparatus includes a first element that provides for a supply of a length of optical fiber in tension and has an interface component for maintaining an end of the optical fiber in tension at a first position. The switching apparatus further includes a second element that has a coupling component for detachably maintaining the end of the optical fiber at a second position. The first and second elements are arranged such that the end of the optical fiber is movable between the first and second elements.

Abstract: An optical cross-connect apparatus includes: a plurality of switch units connected to each other via input ports and output ports; a storage unit to store a setting table in which output port information and corresponding input port information are associated together and registered for each optical signal such that the output port information identifies a specific output port, in the output ports, that outputs the optical signal and the input port information identifies a specific input port, in the input ports, that inputs the optical signal; a setting processor to set each switch unit in the plurality of switch units according to the setting table so as to set a wavelength for each optical signal that is input via the input ports or output via the output ports; and an update processor to update the content of the setting table in response to external input.

Abstract: Techniques for designing optical devices that can be manufactured in volume are disclosed. In an exemplary an optical assembly, to ensure that all collimators are on one side to facilitate efficient packaging, all collimators are positioned on both sides of a substrate. Thus one or more beam folding components are used to fold a light beam up and down through the collimators on top of the substrate and bottom of the substrate.

Abstract: A line switching device includes multiple input ports to which signals are input and that include first input ports and second input ports different from the first input ports; multiple output ports that include given output ports; a branch unit that branches first signals input from the first input ports; and a switch that selectively outputs, among second signals input from the second input ports and branched signals branched from the first signals by the branch unit, signals that are to be switched to an output port among the given ports.

Abstract: A method and module for affecting controlled switching of optical signals having different modes of propagation, wherein the module being provided with at least two multi-mode ports MMPs and a plurality of single-mode ports SMPs, the method comprises: inputting at least one multimode optical signal to an MMP of said MMPs; inputting the single mode optical signals to the SMPs; performing mode processing of one or more of the single mode and multi mode optical signals within the switching module, controllably and selectively switching different optical signals inputted to different ports of the module, preferably based on received feedback related to quality information, thereby allowing switching between single mode ports, between multi-mode ports, and between single mode and multi mode ports.

Abstract: A method for automatic confirmation of an optical network element optical modules each having multiple fibres; a fibre shuffle interconnector having ports to which said optical modules are connected; and a configuration unit which performs an automatic configuration of said optical network element by controlling all optical modules connected to said fibre shuffle interconnector to transmit a fibre identifier associated with a fibre of the respective optical module to the respective port of said fibre shuffle interconnector to which said optical module is connected, wherein said fibre shuffle interconnector forwards the received fibre identifier via another port of said fibre shuffle interconnector to another optical module of said optical network element which detects said forwarded fibre identifier being monitored by said configuration unit to generate a connectivity matrix indicating the connection of said optical modules to said fibre shuffle interconnector on the basis of the detected fibre identifiers.

Abstract: Systems and methods according to these exemplary embodiments provide for optical interconnection using optical splitters and interferometer-based optical switching. Optical signals can be routed from an input port to one or more output ports via at least one splitter and at least one interferometer, e.g., a Mach Zehnder interferometer. According to one exemplary embodiment, signal degradation associated with signal splitting is mitigated by using a binary tree of splitters and interferometers between input ports and output ports.

Abstract: A circuit switched optical interconnection fabric includes a first hollow metal waveguide and a second hollow metal waveguide which intersects the first hollow metal waveguide to form an intersection. An optical element within the intersection is configured to selectively direct an optical signal between the first hollow metal waveguide and a second hollow metal waveguide.

Abstract: A mechanical fiber optic switch including a plurality of first optical fibers, having optical interface ends distributed along a longitudinal axis in a plurality of longitudinal levels, two or more of the longitudinal levels including a plurality of optical interface ends in different radial angles. In addition, the switch includes a plurality of second fibers movable relative to the longitudinal axis, such that each of the second fibers can be optically coupled with the optical interface ends of first fibers in a specific respective radial angle. A fiber gripper is adapted to move the second fibers and a movement mechanism is adapted to move the fiber gripper along the longitudinal axis and to achieve relative rotation of the fiber gripper around the longitudinal axis.

Abstract: An opto-mechanical switch produces different optical paths from two optical path sections out of a plurality of optical path sections that are oriented in different spatial directions. The switch has an optical component on which one end of each optical path section impinges, and which is adapted to be moved linearly in a direction of movement at right angles to the optical path sections between different switching positions, in which it selectively couples different optical path sections optically with each other. Further provided is a measuring system for the analysis of fluids, having such an opto-mechanical switch.

Abstract: An optical transmission module includes a first transmission line for transmitting an electric signal, a resistance element used as a termination point, a second transmission line connected to the resistance element, and a surface ground pattern forming a coplanar line through the first and second transmission lines on a surface of a substrate. A modulator-integrated light-emitting element for outputting output light from an output end face is connected to the surface ground pattern. An electrode pad for modulator driving is located near the output end face on a top face of the modulator-integrated light-emitting element. The first transmission line and the electrode pad are connected by a first wire. The electrode pad and the second transmission line are connected by a second wire. A first notch portion is located in the substrate at a point of intersection between a propagation path of output light of the modulator integrated light-emitting element and a first side face of the substrate.

Abstract: An optical switch comprises a plurality of input ports and a plurality of out port ports; a plurality of displaceable optical elements for directing beams from a selected input to a selected output; wherein the number of displaceable elements substantially corresponds to either the number of input ports or the number of output ports.

Abstract: A system and method of asymmetrical fiber or waveguide spacing comprising, in general, an asymmetrical fiber concentrator array (FCA), wherein an offset in the front face spacing of the output waveguides relative to the input waveguides functions to reduce or eliminate the introduction of static back reflection, and static in-to-in crosstalk into a fiber by an optical switch, but does not impose the cost, complexity, and insertion loss penalties brought about by additional components.

Abstract: An optical coupling device including: at least a first input port for delivering an optical input signal beam that includes a plurality of wavelength channels; at least a first optical output port for receiving an optical output signal beam; a wavelength dispersion element for spatially separating the plurality of wavelength channels in the optical input signal beam to form a plurality of spatially separated wavelength channel beams; an optical coupling device for independently modifying the phase of each of the spatially separated wavelength channel beams such that, for at least one wavelength channel beam, a selected fraction of the light is coupled to the first output port and a fraction of the light is coupled away from the first output port.

Abstract: An electrical switching device, especially a high-frequency switching device, comprising an elongate electrical switching element, a contact end of which is disposed between two opposite contact elements that are transversally spaced apart from each other. The switching element can be selectively moved perpendicularly to the longitudinal direction thereof towards one or the other opposite contact element by two adjusting elements that are located on both sides next to the switching element. In order to eliminate or at least reduce frictional processes and the risk of the electrical contact being damaged by abrasion, the switching element is made at least in part of magnetic material while the adjusting elements are formed by two magnet assemblies, the magnetic force of one magnet assembly or the other magnet assembly being selectively reducible or increasable.

Abstract: Subterranean oilfield sensor systems and methods are provided. The subterranean oilfield sensor systems and methods facilitate downhole monitoring and high data transmission rates with power provided to at least one downhole device by a light source at the surface. In one embodiment, a system includes uphole light source, a downhole sensor, a photonic power converter at the downhole sensor, an optical fiber extending between the uphole light source and the photonic power converter, and downhole sensor electronics powered by the photonic power converter. The photonic power converter is contained in a high temperature resistant package. For example, the high temperature resistant package and photonic power converter may operate at temperatures of greater than approximately 100° C.

Abstract: This invention pertains to optical fiber transmission networks, and is particularly relevant to transmission of high volume of data and voice traffic among different locations. In particular, the improvement teaches improvements to an optical transport system to allow for efficient and flexible network evolution.