Patent Publication Number: US-11658452-B2

Title: Powering up an optical amplifier in an optical line system

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to optical networks. More particularly, the present disclosure relates to automatically powering up an optical amplifier during a process when the optical amplifier is being installed in an optical line system. 
     BACKGROUND 
     Optical communication networks are configured to propagate data between pairs of network devices (e.g., client devices, servers, etc.) over multiple optical communication links throughout the network. Since there is an ever-growing need for more and more communication services, optical communication networks continue to grow while new optical communication networks continue to be added. With expanding communication system infrastructures, there is often a need to add optical amplifiers to enable data propagation over a span of optical fibers. 
     When trucks are rolled out in the field to install line amplifiers (e.g., Intermediate Line Amplifiers or ILAs) at certain installation sites, the installers typically need to make sure the optical fibers and patch panels are properly connected to a newly installed amplifier module at the sites. When long optical links are built between two nodes in the optical communication network, truck-rolls may be deployed asynchronously. In other words, when a line amplifier (e.g., ILA) is being installed at one site, there is no guarantee that line amplifiers have already been installed at upstream or downstream sites. Therefore, installers may not be able to determine if a line amplifier is properly connected to the optic fibers at the installation site, but instead may only rely on local visibility regarding fiber connectivity. 
     In conventional installation processes, fibers may be tested using Optical Time-Domain Reflectometry (OTDR) traces. Once upstream nodes from a section head are connected with each other, light is able to flow through from section head (or from some other upstream source) to complete a local ILA node calibration for a given direction. Then, the fibers may be cleaned before being connected to the line amplifiers. However, since end-to-end light connectivity may or may not be present at this point, the installers may not be able to test the connectivity and would thus leave the site. 
     In addition to connectivity issues, other issues may arise at an installation site that may be not detected using conventional processes. For example, if connectors along the patch panels are dirty or loose, the line amplifier may experience high back-reflection, which may lead to non-linear multi-path interference issues. In response, the amplifier may typically reduce the total output power automatically (e.g., to less than about 10 dBm). However, at this level, it would not be possible to calibrate the amplifier and the amplifier would be unable to carry traffic beyond a certain limit. 
     Therefore, in such case when issues are later detected in a newly installed line amplifier, the installers would be required to return to the field to fix potential fiber issues at the site. Of course, deploying installers multiple times to install a line amplifier would be very costly to vendors. Not only would operational expenditures increase with multiple deployments, but also there would be a delay in powering up and utilizing the amplifier (e.g., turn-up). Therefore, there is a need in the field of line amplifier installation to provide systems and methods for overcoming the deficiencies currently experienced in the field today. 
     BRIEF SUMMARY 
     The present disclosure is directed to systems, methods, and non-transitory computer-readable media associated with line amplifiers and external control devices for executing bootstrap and/or power-up procedures when a line amplifier or optical amplifier card is first installed along an optical link joining two adjacent nodes in a communications network. According to one implementation, an optical amplifier includes one or more gain units each configured to amplify an optical signal; a processing device; and a memory device configured to store a bootstrap program having instructions that, when executed, enable the processing device to block an input to the one or more gain units, and cause the optical amplifier to operate in an Amplified Spontaneous Emission (ASE) mode. The instructions can further enable the processing device to, in response to a detection of a valid power level, switch the optical amplifier from the ASE mode to a regular operating mode, and unblock the input to the one or more gain units to allow operation of the optical amplifier in the regular operating mode. Detection of the valid power level can include one or more of determining that an input optical power is above a shutoff threshold, and confirming connectivity with an upstream Optical Supervisory Channel (OSC) device. Detection of the valid power level can further include determining that a back-reflection detected at an output of the optical amplifier is below a predetermined threshold. 
     The instructions can further enable the processing device to automatically power up the optical amplifier to operate in the ASE mode in absence of any instructions from higher layer controller or processing device. The processing device can be configured to automatically power up the optical amplifier to operate in ASE mode independent of any upstream or downstream connectivity and fault conditions. The optical amplifier can be one of an intermediate line amplifier newly installed in the optical line system intermediately between two adjacent nodes and connected to a channel multiplexer or demultiplexer. The optical amplifier can further include a light blocking device connected to the input to the one or more gain units, wherein blocking the input to the one or more gain units includes controlling the light blocking device to shut off optical power to the one or more gain units. The one or more gain units can include one or more controllable gain units, and wherein blocking the input to the one or more gain units includes shutting off the one or more controllable gain units. The one or more gain units can further include one or more ASE-generating units configured to enable the optical amplifier to operate in the ASE mode. Operating in the ASE mode can include providing a power level below a fiber damage threshold level and above a level configured to enable detection of back-reflection at an output of the optical amplifier. 
     In other embodiments, a method includes steps and a mon-transitory computer-readable medium configured to store computer logic includes instructions that, when executed, cause one or more processing devices to perform the steps. The steps include, responsive to executing a bootstrap program for an optical amplifier having one or more gain units each configured to amplify an optical signal, causing a block of an input to the one or more gain units; and causing the optical amplifier to operate in an Amplified Spontaneous Emission (ASE) mode. The steps can further include, in response to a detection of a valid power level, switching the optical amplifier from the ASE mode to a regular operating mode; and causing an unblock of the input to the one or more gain units to allow operation of the optical amplifier in the regular operating mode. The executing can include automatically powering up the optical amplifier to operate in the ASE mode in absence of any instructions from higher layer controller or processing device. The causing the block can include controlling a light blocking device to shut off optical power to the one or more gain units. The causing the block can include shutting off one or more controllable gain units. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is illustrated and described herein with reference to the various drawings. Like reference numbers are used to denote like components/steps, as appropriate. Unless otherwise noted, components depicted in the drawings are not necessarily drawn to scale. 
         FIG.  1    is a diagram illustrating a portion of an optical communication network, according to various embodiments. 
         FIG.  2    is a schematic diagram illustrating an installation site where a first type of line amplifier is installed along a link between two adjacent nodes, according to various embodiments. 
         FIG.  3    is a schematic diagram illustrating an installation site where a bi-directional test is performed for testing the first type of line amplifier shown in  FIG.  2   , according to various embodiments. 
         FIGS.  4 A and  4 B  are diagrams illustrating portions of an optical communication network in which another test is performed for testing line amplifiers from a section head, according to various embodiments. 
         FIG.  5    is a diagram illustrating a portion of an optical communication network in which another bi-directional test is performed to test line amplifiers, according to various embodiments. 
         FIG.  6    is a block diagram illustrating an on-board controller arranged on an optical amplifier card for controlling a bootstrapping process when a line amplifier is installed, according to various embodiments. 
         FIG.  7    is a block diagram illustrating a supervisory device for controlling operations associated with the installation of a line amplifier, according to various embodiments. 
         FIG.  8    is a schematic diagram illustrating an optical amplifier card where the on-board controller of  FIG.  6    is arranged thereon, according to various embodiments. 
         FIG.  9    is a schematic diagram illustrating an optical amplifier card controllable by the supervisory device of  FIG.  7   , according to various embodiments. 
         FIG.  10    is a schematic diagram illustrating another optical amplifier card configured with the on-board controller of  FIG.  6   , according to various embodiments. 
         FIG.  11    is a schematic diagram illustrating yet another optical amplifier card configured with the on-board controller of  FIG.  6   , according to various embodiments. 
         FIG.  12    is a flow diagram illustrating a process for controlling a bootstrapping procedure for a line amplifier newly installed in an optical communication network, according to various embodiments. 
         FIG.  13    is a diagram illustrating a portion of an optical communication network including amplifiers on the local add/drop, according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates to optical communication networks and systems and methods for controlling a bootstrapping or turn-up process when a line amplifier is newly installed along an optical communication link between two adjacent nodes in the optical communication network. With the control features described with respect to the various embodiments of the present disclosure, it is possible to automatically power-up and test a newly-installed amplifier module to ensure that the amplifier module is properly installed. The control aspects described here allow the amplifier module to be installed essentially as a plug-and-play device. As a result of controlling the start-up process and testing the amplifier modules during installation regarding proper local connectivity, as defined in the present disclosure, it is possible to reduce the number of truck-roll deployments, thereby reducing the waste of time and money to vendors caused by repeated deployments. The amplifier testing can be performed independently of the condition of fiber connectivity at upstream or downstream sites. 
       FIG.  1    is a diagram illustrating an embodiment of an optical communication network  10 . In this embodiment, the optical communication network  10  includes nodes A, B, C, D, which are located at various distances from each other. The nodes A, B, C, D are connected with each other via a number of optical communication links  12 . Attenuation of optical signals is based on the length of the optical communication links  12 , among other things. If the length is too great, the optical signals may be attenuated to an undesirable degree. Thus, it may be necessary to install Intermediate Line Amplifiers (ILAs)  14  or repeaters along the length of the optical communication links  12  to boost the signals as needed for transmission from one node to another. 
     As shown in  FIG.  1   , nodes A and B are close enough to each other where no ILA  14  is needed between them. However, one ILA  14  is positioned along the link  12  between nodes A and C and one is positioned between nodes B and C. Two ILAs  14  are positioned between nodes C and D, and three ILAs  14  are positioned between nodes B and D. 
     According to the embodiments of the present disclosure, portions of the optical communication network  10  may be a newly installed. For example, one or more nodes may be newly added, one or more optical communication links  12  may be added between new or existing nodes, and one or more ILAs  14  may be added to new or existing optical communication link  12 . In these cases where an ILA  14  is to be installed, the embodiments of the present disclosure may be utilized to automatically power up and test the connectivity of the ILA  14  in the optical communication network  10 . 
       FIG.  2    is a schematic diagram illustrating an embodiment of an installation site  20  where a first type of line amplifier  22  (e.g., ILA) is installed along a link (e.g., optical communication link  12 ) between an upstream fiber coil  24  and a downstream fiber coil  26 . The upstream fiber coil  24  may be connected to a first node and the downstream fiber coil  26  may be connected to a second node in a network. 
     In this embodiment, a Point-to-Point Link (PPL)  28  may be connected between the upstream fiber coil  24  and the line amplifier  22 . The PPL  28  is connected to the upstream fiber coil  24  via connector  30  and is connected to the optical amplifier card  22  via connector  32 . The connector  32 , for example, may at least partially reside on an input faceplate of the optical amplifier card  22 . The PPL  28  may be monitored by a first Fault Management System (FMS). 
     Additional PPLs  34 ,  36 ,  38  are connected between the line amplifier  22  and the downstream fiber coil  26 . The PPL  34  is connected to the line amplifier  22  via connector  40  and is connected to the PPL  36  via connector  42 . The connector  40 , for example, may at least partially reside on an output faceplate of the optical amplifier card  22 . Also, the PPL  36  is connected to the PPL  38  via connector  44 , and the PPL  38  is connected to the downstream fiber coil  26  via connector  46 . The PPLs  34 ,  36 ,  38  may be monitored by a second FMS. 
     The line amplifier  22  receives input optical signals from connector  32 , amplifies the optical signals, and transmits (repeats) the amplified optical signals as output via connector  40 . According to this embodiment of  FIG.  2   , the line amplifier  22  includes a gain unit  48  (e.g., amplifier), a Variable Optical Attenuator (VOA)  50 , a first monitor  52  for measuring total optical power, and a second monitor  54  for measuring back-reflection. 
     Various techniques may be executed for testing connectivity of a line amplifier (e.g., ILA  14 , line amplifier  22 , etc.), such as during an amplifier installation process. Of course, one technique includes making an initial installation and then revisiting the site for follow-up maintenance if faults are discovered at a later period as calibration runs and lights show up from upstream. Another technique includes manually disconnecting fibers and putting optical loopback connectors to verify amplifier connectivity, as described below with respect to  FIG.  3   . Still another technique may include running Optical Time-Domain Reflectometry (OTDR) traces in a co-propagating direction, as described below with respect to  FIG.  4   . However, since trace detected events could be unreliable without following explicit setup and fiber patch recommendations, a technician may need to manually inspect the traces to understand if any loss or reflection from the trace can potentially cause any trouble for Erbium-Doped Fiber Amplifiers (EDFAs) in future use. Also, existing hardware designs do not guarantee a smooth installation process and may force vendors to send installers multiple times to the field for a successful turn-up. 
       FIG.  3    is a schematic diagram illustrating an embodiment of the installation site  20  of  FIG.  2    where a bi-directional test is performed for testing the line amplifier  22  shown in  FIG.  2   . In  FIG.  3   , the same references numerals (with single prime and double prime characters) are used to designate the same elements shown in  FIG.  2   , whereby the top set of elements is marked with single prime characters to represent transmission in one direction (i.e., shown from left to right on the page) and whereby the bottom set of elements is marked with double prime characters to represent transmission in the opposite direction (i.e., shown from right to left on the page). 
     According to this setup, the optical amplifier card  22  (i.e.,  22 ′ and  22 ″) can be tested at the stand-alone ILA site (e.g., installation site  20 ) for Optical Return Loss (ORL) using a fiber disconnect process. The ORL may be equal to the total optical power (e.g., measured by the monitor  52 ) minus the back-reflection (e.g., measured by the monitor  54 ) and may be expressed in units of dB. The fiber disconnect process includes installing the line amplifier  22  in the field, disconnecting an input fiber, making a loopback connection at an output, and then generating power from the gain unit  48  (e.g., EDFA) to test the faceplate output connectors  40 . 
     More specifically, the fiber disconnect process shown in  FIG.  3    may include the following eight steps: 
     1. Select one direction, where a first direction points from the upstream fiber coil  24 ′ to the downstream fiber coil  26 ′ (top set) and a second direction points from the downstream fiber coil  26 ″ to the upstream fiber coil  24 ″ (bottom set). In this example, the top set (upstream to downstream) is selected. 
     2. Disconnect the input connector  30 ′ from the upstream fiber coil  24 ′ (to create disconnection  60 ) and disconnect the input connector  46 ″ from the downstream fiber coil  26 ″ (to create disconnection  62 ) for disconnecting inputs from both directions. 
     3. For the selected direction (top set), disconnect the output connector  46 ′ from the downstream fiber coil  26 ′ (to create disconnection  64 ) and connect a pad  66  between connectors  46 ′ and  46 ″. The pad  66  may be configured to provide an attenuation of about 20 dB. 
     4. For the selected amplifier (e.g., gain unit  48 ′) for which the upstream fiber coil  24 ′ is disconnected, put the gain unit  48 ′ into “power” mode. This is an important step to ensure that the input fiber coil  24 ′ is disconnected before the gain unit  48 ′ is put into power mode. Otherwise, damage may be caused to fiber tips of the upstream fiber coil  24 ′. 
     5. Do not disconnect the output connector  30 ″ from the upstream fiber coil  24 ″ for the other direction. 
     6. Verify that there is enough light to achieve satisfactory ORL conditions on both directions before leaving the site. 
     7. If ORL is reported to be greater than 25 dB for both directions, remove the pad  66  and reconnect input and output connectors  30 ′,  46 ′,  46 ″ to fiber coils  24 ′,  26 ′,  26 ″, respectively. 
     8. Once the ORL test is done, the optical amplifier card  22  can be set back to a gain mode or gain-clamp mode. 
     One issue with the embodiment of  FIG.  3    is that the installer is required access to the optical amplifier card information after commissioning of a controller module (or other device for controlling or supervising the line amplifier) and manipulating the fiber plants (disconnecting and reconnecting multiple times). However, this does not guarantee that the fibers will be clean when the artificial loopback connector (e.g., pad  66 ) is removed. Also, the procedures described with respect to  FIG.  3    may be considered to add an extra burden to installers since they would need to follow rigorous step-by-step procedures of disconnecting and reconnecting fiber spans, creating a loopback at an output, etc. 
       FIGS.  4 A and  4 B  are diagrams illustrating an optical communication network  70  in which another test is performed for testing line amplifiers from a section head  72 . The optical communication network  70  may include a plurality (N) of line amplifiers connected by a number (N−1) fiber coils. The tests described with respect to  FIGS.  4 A and  4 B  include generating Amplified Spontaneous Emission (ASE) signals at or near the section head  72 . For example, the ASE signals may be configured as channel holders for filling up the channels in an optical spectrum. The ASE tests may have some benefits over the loopback test described above with respect to  FIG.  3   . For example, in the ASE generation test of  FIG.  4   , ASE is generated from a section-head instead of requiring actions at the installation site. Two possible ASE generation processes may be followed. 
     As shown in  FIG.  4 A , a first process includes generating ASE before a section multiplexer switching element  74  and then using the spectrum switching feature of the section multiplexer switching element  74  to generate channelized ASE holders. For example, this may be incorporated in an optical line system with ASE-loading capabilities. 
     According to a second process,  FIG.  4 B  includes generating ASE from a first optical amplifier (or first optical amplifier card) in the section. The process includes ensuring that all pixels at the section multiplexer switching element  74  are at a blocked state to prevent any light at an input to the first optical amplifier  76  while doing ASE generation to prevent Q-switching impact. 
     The processes of  FIGS.  4 A and  4 B  allow a line amplifier or optical amplifier card for a given direction to be lit following the installation process and configuration processes of all upstream spans and amplifier (e.g., Reconfigurable Optical Add/Drop Multiplexer (ROADM)) sites. When an amplifier is out of a shut-off state, it can detect high back-reflections and generate alarms for installers for debugging. 
       FIG.  5    is a diagram illustrating the optical communication network  70  of  FIGS.  4 A and  4 B  in which a bi-directional test is performed to test one or more line amplifiers. Both methods for section-head ASE generation depend on upstream connectivity. However, as discussed above, it is likely that this connectivity is not available when installers are initially sent in the field for installation. 
     In addition, both methods provide directional turn-up in both directions (east-to-west and west-to-east). This means that when installers are at a line amplifier installation site and one direction is able to light up, there is no guarantee when the line amplifier for the other direction will light up, since the light-up process to calibrate line amplifiers from one span to the next is sequential and may take a substantial amount of time. For example, with a 50× span Optical Multiplex Section (OMS), the last span may take about two hours before seeing light in a success path (e.g., no fault in upstream nodes) in an ASE-loaded system. 
     The process is also dependent on line-fiber faults in upstream spans. That means, for a given direction, until all upstream amplifier nodes are declared non-faulted and calibrated, the local amplifier keeps waiting until enough power is received to come out of the shut-off state and trigger a calibration process. For example, the calibration process may include setting a target gain, gain-tilt, power, etc. Hence, this uncertainty effectively may force installers to use the process of  FIG.  3    that involves disconnecting fiber and testing the line amplifier locally regardless of sectional turn-up approaches. 
     Also, the installation process may include using OTDR traces to detect fiber issues in the co-propagating direction that can potentially cause the line amplifiers (e.g., ILAs  14 , optical amplifier cards  22 , EDFAs, etc.) to move into an Automatic Power Reduction (APR) state, which may be due to high back-reflection. However, scanning using external OTDR may not guarantee that the faceplate ports and connectors would be clean. Even using a built-in OTDR system (equipped within the optical amplifier card), it can be difficult to successfully detect all loss and reflection events. 
     For example, it can be difficult to detect loss and back-reflection if there are back-to-back amplifier cards (e.g., two cascaded EDFAs, a combination of an EDFA and a Raman amplifier, etc.) and there is not enough fiber patch cord between them to detect faceplate events. The length of any patch panel cord from the faceplate to the fiber spool, for instance, may be below the OTDR trace deadzone. In this case, the OTDR may fail to detect an event. For example, a 30 ns OTDR trace having a 35 m deadzone would mean that events within 35 m before or after the faceplate (or any patch panel connector event shorter than 35 m) are not detected. 
     Since the high reflection issue for EDFA is a booster direction issue (co-propagating direction), there is no such recommendation for installers to follow an explicit minimum length for each patch panels. Hence, the built-in OTDR detection system may not be useful in this case for detecting future APR conditions for EDFAs. 
       FIG.  6    is a block diagram illustrating an embodiment of an on-board controller  80  arranged on an optical amplifier card for controlling a bootstrapping process when a line amplifier is installed. As the name suggests, the on-board controller  80  may be housed on the optical amplifier card itself to allow a self-initiated turn-up process. In this embodiment, the on-board controller  80  includes a processing device  82 , a memory device  84 , and Input/Output (I/O) interfaces  86  in communication with each other via a local interface  90 . 
     The on-board controller  80  also includes a bootstrap program  92 . The bootstrap program  92  may be configured in software and/or firmware and stored in the memory device  84 . In other embodiments, the bootstrap program  92  may additionally or alternatively be configured in hardware of the processing device  82 . The bootstrap program  92  is configured to automatically power up a line amplifier (or optical amplifier card) when it is initially installed in an optical line to allow the amplifier to operate in an optical network. 
     The I/O interfaces  86  in this embodiment may include buttons, switches, etc. to allow an installer to indicate to the on-board controller  80  that the device (e.g., line amplifier, optical amplifier card, etc.) has been installed and is ready for the bootstrap process. In other embodiments, the line amplifier may automatically perform the bootstrap process. Also, the I/O interfaces  86  may include one or more indicators (e.g., LEDs, etc.) for indicating when the progress of the bootstrap process. For example, when the bootstrap process is complete, the I/O interfaces  86  may illuminate a green LED indicating completion. 
       FIG.  7    is a block diagram illustrating an embodiment of a supervisory device  100  for controlling operations associated with the installation of a line amplifier. As opposed to the on-board controller  80  described with respect to  FIG.  6   , the supervisory device  100  may be housed externally to the line amplifier or optical amplifier card. Nevertheless, the supervisory device  100  may be configured to communicate with the line amplifier or optical amplifier card to control power-up, turn-up, or bootstrap processes of the amplifier that is newly installed in the optical network. 
     In this embodiment, the supervisory device  100  includes a processing device  102 , a memory device  104 , I/O interfaces  106 , and an interface device  108 . The components  102 ,  104 ,  106 , and  108  may be configured in communication with each other via a local interface  110 . The supervisory device  100  may further include a line amplifier installation manager  112 , which may be configured in hardware, software, and/or firmware in the processing device  102  and/or the memory device  104 . The line amplifier installation manager  112  is configured to control installation processes when a line amplifier is newly installed in an optical system. 
     The interface device  108  may be configured to allow the supervisory device  100  to communicate with one or more external devices and may be connected directly or indirectly to these one or more external devices. As such, one of these external devices may be a newly-installed line amplifier to be controlled by the supervisory device  100  during the installation process. In other embodiments, the interface device  108  may be connected to a communication network (e.g., optical communication network  10 ) for communicating with a local or remote newly-installed line amplifier. 
     In the illustrated embodiments of  FIGS.  6  and  7   , the on-board controller  80  and supervisory device  100  may be a digital computer that, in terms of hardware architecture, generally includes processing devices  82 ,  102 , memory devices  84 ,  104 , Input/Output (I/O) interfaces  86 ,  106 , and interface device  108 . The memory devices  84 ,  104  may include a data store, database, or the like. It should be appreciated by those of ordinary skill in the art that  FIGS.  6  and  7    depict the on-board controller  80  and supervisory device  100  in a simplified manner, where practical embodiments may include additional components and suitably configured processing logic to support known or conventional operating features that are not described in detail herein. The components (i.e.,  82 ,  84 ,  86 ) are communicatively coupled via the local interface  90  in  FIG.  6    and the components (i.e.,  102 ,  104 ,  106 ,  108 ) are communicatively coupled via the local interface  110  in  FIG.  7   . The local interfaces  90 ,  110  may be, for example, but not limited to, one or more buses or other wired or wireless connections. The local interfaces  90 ,  110  may have additional elements, which are omitted for simplicity, such as controllers, buffers, caches, drivers, repeaters, receivers, among other elements, to enable communications. Further, the local interfaces  90 ,  110  may include address, control, and/or data connections to enable appropriate communications among the components. 
     The processing devices  82 ,  102  are hardware devices adapted for at least executing software instructions. The processing devices  82 ,  102  may be any custom made or commercially available processor, a Central Processing Unit (CPU), an auxiliary processor among several processors associated with the on-board controller  80  and supervisory device  100 , a semiconductor-based microprocessor (in the form of a microchip or chip set), or generally any device for executing software instructions. When the on-board controller  80  and supervisory device  100  are in operation, the processing devices  82 ,  102  may be configured to execute software stored within the memory devices  84 ,  104 , to communicate data to and from the memory devices  84 ,  104 , and to generally control operations of the on-board controller  80  and supervisory device  100  pursuant to the software instructions. 
     It will be appreciated that some embodiments of the processing devices  82 ,  102  described herein may include one or more generic or specialized processors (e.g., microprocessors, CPUs, Digital Signal Processors (DSPs), Network Processors (NPs), Network Processing Units (NPUs), Graphics Processing Units (GPUs), Field Programmable Gate Arrays (FPGAs), and the like). The processing devices  82 ,  102  may also include unique stored program instructions (including both software and firmware) for control thereof to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more Application Specific Integrated Circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic or circuitry. Of course, a combination of the aforementioned approaches may be used. For some of the embodiments described herein, a corresponding device in hardware and optionally with software, firmware, and a combination thereof can be referred to as “circuitry” or “logic” that is “configured to” or “adapted to” perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc., on digital and/or analog signals as described herein for the various embodiments. 
     The I/O interfaces  86 ,  106  may be used to receive user input from and/or for providing system output to one or more devices or components. User input may be provided via, for example, a keyboard, touchpad, a mouse, and/or other input receiving devices. The system output may be provided via a display device, monitor, Graphical User Interface (GUI), a printer, and/or other user output devices. I/O interfaces  86 ,  106  may include, for example, one or more of a serial port, a parallel port, a Small Computer System Interface (SCSI), an Internet SCSI (iSCSI), an Advanced Technology Attachment (ATA), a Serial ATA (SATA), a fiber channel, InfiniBand, a Peripheral Component Interconnect (PCI), a PCI eXtended interface (PCI-X), a PCI Express interface (PCIe), an InfraRed (IR) interface, a Radio Frequency (RF) interface, and a Universal Serial Bus (USB) interface. 
     The interface device  108  may be used to enable the supervisory device  100  to communicate over a network, such as the optical communication network  10 , the Internet, a Wide Area Network (WAN), a Local Area Network (LAN), and the like. The interface device  108  may include, for example, an Ethernet card or adapter (e.g., 10BaseT, Fast Ethernet, Gigabit Ethernet, 10 GbE) or a Wireless LAN (WLAN) card or adapter (e.g., 802.11a/b/g/n/ac). The interface device  108  may include address, control, and/or data connections to enable appropriate communications on the optical communication network  10 . 
     The memory devices  84 ,  104  may include volatile memory elements (e.g., Random Access Memory (RAM)), such as Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Static RAM (SRAM), and the like, nonvolatile memory elements (e.g., Read Only Memory (ROM), hard drive, tape, Compact Disc ROM (CD-ROM), and the like), and combinations thereof. Moreover, the memory devices  84 ,  104  may incorporate electronic, magnetic, optical, and/or other types of storage media. The memory devices  84 ,  104  may have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processing devices  82 ,  102 . The software in memory devices  84 ,  104  may include one or more software programs, each of which may include an ordered listing of executable instructions for implementing logical functions. The software in the memory devices  84 ,  104  may also include suitable Operating Systems (O/Ss) and one or more computer programs. The O/Ss essentially control the execution of other computer programs, and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The computer programs may be configured to implement the various processes, algorithms, methods, techniques, etc. described herein. 
     The memory devices  84 ,  104  may include a data store used to store data. In one example, the data store may be located internal to the on-board controller  80  and supervisory device  100  and may include, for example, an internal hard drive connected to the local interfaces  90 ,  110  in the on-board controller  80  and supervisory device  100 . Additionally, in another embodiment, the data store may be located external to the on-board controller  80  and supervisory device  100  and may include, for example, an external hard drive connected to the Input/Output (I/O) interfaces  86 ,  106  (e.g., SCSI or USB connection). In a further embodiment, the data store may be connected to the on-board controller  80  and supervisory device  100  through a network and may include, for example, a network attached file server. 
     Moreover, some embodiments may include a non-transitory computer-readable storage medium having computer readable code stored in the memory devices  84 ,  104  for programming the on-board controller  80  and supervisory device  100  or other processor-equipped computer, server, appliance, device, circuit, etc., to perform functions as described herein. Examples of such non-transitory computer-readable storage mediums include, but are not limited to, a hard disk, an optical storage device, a magnetic storage device, a Read Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), and Electrically Erasable PROM (EEPROM), Flash memory, and the like. When stored in the non-transitory computer-readable medium, software can include instructions executable by the processing devices  82 ,  102  that, in response to such execution, cause the processing devices  82 ,  102  to perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for the various embodiments. 
     The bootstrap program  92  and line amplifier installation manager  112  may include similar processes as described with respect to the various embodiments of the present disclosure for conducting installation or set-up steps when a line amplifier or optical amplifier card is being installed or has newly been installed in an optical communication link (e.g., optical communication link  12 ). 
       FIG.  8    is a schematic diagram illustrating an optical amplifier card  120 , which may be part of a line amplifier device installed at an installation site. The optical amplifier card  120  in this embodiment includes the on-board controller  80  of  FIG.  6    arranged thereon. The optical amplifier card  120  also includes an input faceplate connector  122  configured for connecting the optical amplifier card  120  to an upstream fiber coil (not shown) and an output faceplate connector  124  configured for connecting the optical amplifier card  120  to a downstream fiber coil (not shown). 
     Furthermore, the optical amplifier card  120  includes an Optical Supervisory Channel (OSC) receiver filter  126  for detecting external OSC control signals from an external control device and providing these OSC control signals to the on-board controller  80 . An input total power monitor  128  is configured to detect the total optical power at the input of the optical amplifier card  120 . The optical amplifier card  120  further includes an optical blocking device  130  configured to block light to a gain unit  132  as needed and to allow light to pass to the gain unit  132  as needed. The gain unit  132  amplifies the optical signals propagating through the optical amplifier card  120 . In this embodiment, the gain unit  132  may include a fixed amplification level. Also, the gain may be adjusted using a Variable Optical Attenuator (VOA) device  134 , which, in some embodiments, may also be controlled by the on-board controller  80 . 
     The optical amplifier card  120  further includes a OSC transmitter filter  136  for providing OSC control signals from the on-board controller  80 . Also, the optical amplifier card  120  includes an output total power monitor  138 , which is configured to detect the total optical power at the output of the optical amplifier card  120 . A back-reflection monitor  140  is configured to detect optical back-reflections that are reflected back from the output of the optical amplifier card  120 . In addition, one or more indicators  142  may be arranged on the optical amplifier card  120  and/or on a housing in which the optical amplifier card  120  resides. The one or more indicators  142  may be configured to provide visual and/or audible indications to a user (e.g., installer) regarding the status of installation, boot-up, power-up, turn-up processes. These processes may be executed as a result of the optical amplifier card  120  being newly installed or based on other situations where optical amplifier card  120  may be re-booted or re-introduced into an optical link. 
     Therefore, the optical amplifier card  120  includes a modification of conventional amplifier card designs by introducing an optical blocker (i.e., the optical blocking device  130 ) or switch at the input of the amplifier gain block (i.e., the gain unit  132 ). The optical blocking device  130  is configured to block any incoming light to the amplifier. The on-board controller  80  is configured to introduce a novel bootstrap process for the card turn-up by putting the gain unit  132  (e.g., EDFA) in an Amplified Spontaneous Emission (ASE) generation mode in which an ASE source is configured to provide ASE channel holders into the line of the optical amplifier card  120 , such as at the input of the gain unit  132  (as shown) or elsewhere in the line. 
     The main input remains blocked until a “connectivity” factor and a “cleanliness” factor have been verified. For example, the connectivity factor may be related to the proper connectivity between the optical amplifier card  120  and an upstream fiber coil (via the input faceplate connector  122 ) and/or the proper connectivity between the optical amplifier card  120  and a downstream fiber coil (via the output faceplate connector  124 ). The cleanliness factor may be related to proper cleanliness of fibers of the upstream and downstream fiber coils when being connected to the input faceplate connector  122  and output faceplate connector  124 , respectively. By providing automatic control of the turn-up process, the optical amplifier card  120  may be considered to be a “plug and play” device to allow the installers to simply install the optical amplifier card  120  without requiring manual testing. Also, an installer can receive relatively instant feedback regarding the status of the newly-installed optical amplifier card  120  such that the installation can be made right during this initial visit to the installation site, without any dependency on a controller module or upstream commissioning and fiber connectivity. 
       FIG.  9    is a schematic diagram illustrating another embodiment of an optical amplifier card  150 . In this embodiment, the optical amplifier card  150  is configured to be controllable by the supervisory device of  FIG.  7   . The optical amplifier card  150  includes many of the same elements as described above with respect to the optical amplifier card  120  of  FIG.  8   . For example, the optical amplifier card  150  include the elements  122 ,  124 ,  126 ,  128 ,  130 ,  132 ,  134 ,  136 ,  138 ,  140 , and  142  described above. However, instead of an on-board controller (e.g., on-board controller  80 ), the optical amplifier card  150  is configured to be controlled by the supervisory device  100  described with respect to  FIG.  7    or controlled by another control device external to the optical amplifier card  150  using external communication interfaces  144 . 
     The optical amplifier cards  120 ,  150  are therefore equipped with an optical blocker or switch (i.e., optical block device  130 ) at the input of the gain unit  132  that can effectively block all or most of the light to the gain unit  132 . At installation time, when the optical amplifier card  120 ,  150  is turned up for the first time, the controller (e.g., on-board controller  80 , supervisory device  100 , etc.) is configured to keep the input to the gain unit  132  in a blocked state while powering up the optical amplifier card  120 ,  150  in an ASE generation mode. The ASE generation mode may be achieved by allowing an ASE source to generate ASE channel holder signals having enough power to allow detection of back-reflections (e.g., by the back-reflection monitory  140 ) at the output of the optical amplifier card  120 ,  150 , but nevertheless is low enough where the risk of fiber damage is minimized (e.g., below a threshold of 10 dBm). 
     After powering up in the ASE generation mode, the controller  80 ,  100  is configured to automatically unblock the input to the gain unit  132  (e.g., by allowing light to pass through the optical block device  130 , by “closing” a switch, etc.). Also, at this point, the controller  80 ,  100  is configured to flip the optical amplifier card  120 ,  150  from the ASE generation mode to a regular operating mode, such as a gain/gain-clamp or power mode. According to some embodiments, the controller  80 ,  100  is configured to flip the amplifier mode from ASE generation to regular operation mode  1 ) when the back reflection (e.g., detected by the monitor  140 ) at the amplifier output is below a certain threshold, and 2) when a valid input power (e.g., detected by the input total power monitor  128 ) is above a predetermined shut-off threshold of the optical amplifier card  120 ,  150  or when the OSC receiver filter  126  detects OSC connectivity from an upstream supervisory/control device or supervisory device  100 . It should be noted that the optical blocking device  130  is placed after the OSC receiver filter  126  and/or after the input total power monitor  128  at the input of the optical amplifier card  120 ,  150  to enable the automatic control processes described above. 
       FIGS.  10  and  11    are schematic diagrams illustrating additional embodiments of optical amplifier cards. It should be noted that although the optical amplifier cards as described in FIGS.  10  and  11  are controlled by on-board controllers, the optical amplifier cards, according to alternative embodiments, may be controlled by one or more external supervisory devices. 
       FIG.  10    shows an optical amplifier card  160  configured to be controlled by the on-board controller  80  of  FIG.  6    or other local control device. In this embodiment, the optical amplifier card  160  includes an input faceplate connector  162  configured for connecting the optical amplifier card  160  to an upstream fiber coil (not shown) and an output faceplate connector  164  configured for connecting the optical amplifier card  160  to a downstream fiber coil (not shown). 
     Furthermore, the optical amplifier card  160  includes an Optical Supervisory Channel (OSC) receiver filter  166  for detecting external OSC control signals from an external control device and providing these OSC control signals to the on-board controller  80 . An input total power monitor  168  is configured to detect the total optical power at the input of the optical amplifier card  160 . The optical amplifier card  160  further includes an adjustable gain unit  172 , which may include one or more optical amplifiers. The adjustable gain unit  172  may be controlled by the on-board controller  80  to adjust the amplification or gain of optical signals through the adjustable gain unit  172 . Therefore, the adjustable gain unit  172  may produce a variable amplification level and may therefore differ from the fixed amplification level provided by the gain unit  132  shown in  FIG.  8   . The adjustable gain unit  172  may be configured in various implementations to block (attenuate) light partially or completely and/or can provide no or positive amplification as needed. The optical amplifier card  160  may further include a VOA  174 , which may be controlled by the on-board controller  80  to adjust the gain or attenuation. 
     The optical amplifier card  160 , according to the embodiment of  FIG.  10   , further includes a 1×2 selector  176  (e.g., switch, splitter, etc.) configured to enable selection of one of two paths. A first path  177  is directed to another gain unit  178  and a second path  179  bypasses the gain unit  178 . The gain unit  178  may include one or more optical amplifiers. An ASE source may be used to provide ASE channel holders on the first path  177  to create an ASE generate mode similar to the ASE modes described above. A 2×1 coupler  180  is configured to couple the signals from the two paths  177 ,  179 . Furthermore, the optical amplifier card  160  includes another gain unit  182  (e.g., one or more optical amplifiers) and a VOA device  184  for adjusting the gain/attenuation of optical signals through the optical amplifier card  160 . 
     The optical amplifier card  160  further includes a OSC transmitter filter  186  for receiving OSC control signals from the on-board controller  80 . Also, the optical amplifier card  160  includes an output total power monitor  188 , which is configured to detect the total optical power at the output of the optical amplifier card  160 . A back-reflection monitor  190  is configured to detect optical back-reflections that are reflected back from the output of the optical amplifier card  160 . In addition, one or more indicators  192  may be arranged on the optical amplifier card  160  and/or on a housing in which the optical amplifier card  160  resides. The one or more indicators  192  may be configured to provide visual and/or audible indications to a user (e.g., installer) regarding the status of installation, boot-up, power-up, turn-up processes. These processes may be executed as a result of the optical amplifier card  160  being newly installed or based on other situations where optical amplifier card  160  may be re-booted or re-introduced into an optical link. 
     Therefore, the optical amplifier card  160  also includes a modification of conventional amplifier card designs by allowing one or more gain units  172  and VOAs  174  to provide a blocking function to block incoming light at the input. Again, the on-board controller  80  is configured to introduce novel bootstrap processes for the optical amplifier card  160  for allowing it to turn-up by blocking incoming light while transitioning to an Amplified Spontaneous Emission (ASE) generation mode in which the ASE source is configured to provide ASE channel holders into the first path  177  and essentially in an output line of the optical amplifier card  160 . 
     The main input remains blocked until the “connectivity” factor and the “cleanliness” factor have been verified, as described above. Again, the connectivity factor may be related to the proper connectivity between the optical amplifier card  160  and an upstream fiber coil (via the input faceplate connector  162 ) and/or the proper connectivity between the optical amplifier card  160  and a downstream fiber coil (via the output faceplate connector  164 ). The cleanliness factor, as mentioned above, may be related to proper cleanliness of fibers of the upstream and downstream fiber coils when being connected to the input faceplate connector  162  and output faceplate connector  164 , respectively. By providing automatic control of the turn-up process, the optical amplifier card  160  may be considered to be a “plug and play” device to allow the installers to simply install the optical amplifier card  160  without requiring manual testing. Also, an installer can receive relatively instant feedback regarding the status of the newly-installed optical amplifier card  160  such that the installation can be made right during this initial visit to the installation site, without any dependency on a controller module or upstream commissioning and fiber connectivity. 
       FIG.  11    is a schematic diagram illustrating yet another optical amplifier card  200  configured with the on-board controller  80  (or relying on external control from the supervisory device  100  or other external control devices). The optical amplifier card  200  include many of the same elements as described above with respect to  FIG.  10   . However, in this embodiment, the VOA  174  shown in  FIG.  10    is replaced with a switching element  202 . Also, the ASE source is arranged in this embodiment before the switching element  202 . This implementation also allows the controller (e.g., on-board controller  80 , supervisory device  100 , etc.) to provide the bootstrap, turn-up, power-up procedures described herein. 
     Instead of introducing the extra switch (e.g., optical blocking device  130 ) in the amplifier, as described with respect to  FIGS.  8  and  9   , the embodiments of  FIGS.  10  and  11    include alternative ways of providing input blocking functions. The blocking may be achieved by forcing shutoff to at least one or more internal gain-block stages (e.g., at least gain unit  172 ) and then generating ASE from one or more downstream gain-block stages (e.g., at least gain units  178 ,  182 , etc.) in the ASE generation mode. In some embodiments, the optical amplifiers (e.g., gain units  132 ,  172 ,  178 ,  182 , etc.) may be multi-stage amplifiers. In some cases, these amplifiers may include three stages, four stages, or more. 
       FIG.  12    is a flow diagram illustrating an embodiment of a process  210  for controlling a bootstrapping procedure for a line amplifier newly installed in an optical communication network. In this embodiment, the process  210  includes a step of blocking an input to one or more gain units of a line amplifier, as indicated in block  212 . The process  210  also includes causing the line amplifier to operate in an ASE mode, as indicated in block  214 . While operating in the ASE mode, the process  210  includes determining if a valid power level is detected, as indicated in decision diamond  216 . When a valid power level is detected, the process  210  proceeds to block  218 , which includes the step of switching the line amplifier from the ASE mode to a regular operating mode. Then, the process  210  includes unblocking the input to the one or more gain units to allow operation of the line amplifier in the regular operating mode, as indicted in block  220 . 
     The process  210  may be implemented by the line amplifier itself when equipped with a local controller (e.g., on-board controller  80 ). Otherwise, the process  210  may be implemented on the line amplifier by control instructions from a remote controller device (e.g., supervisory device  100 ). The controllers (e.g., on-board controller  80 , supervisory device  100 , etc.) may include a processing device  82 ,  102  and a memory device  84 ,  104  configured to store a bootstrap program  92 , line amplifier installation manager  112 , or other control processing logic. The logic may include instructions that, when executed, enable the processing device to perform the bootstrapping, turn-up, power-up, installation processes described in the present disclosure. 
     Furthermore, the process  210  may be configured such that, before causing the line amplifier to operate in the ASE mode, the logic may enable the processing device to automatically power up the line amplifier based on the line amplifier being newly installed in an optical line system. The processing device may be configured to automatically power up the line amplifier independent of upstream connectivity and upstream fault conditions. The line amplifier may be an intermediate line amplifier newly installed in the optical line system intermediately between two adjacent nodes. 
     The process  210  of  FIG.  12    may also be configured whereby detection of the valid power level may include one or more of 1) determining that an input optical power is above a shutoff threshold, and 2) confirming connectivity with an upstream Optical Supervisory Channel (OSC) device. Detection of the valid power level may further include determining that a back-reflection detected at an output of the line amplifier is below a predetermined threshold. 
     Also, the process  210  may include utilizing a light blocking device connected to the input to the one or more gain units, whereby blocking the input to the one or more gain units may include controlling the light blocking device to shut off optical power to the one or more gain units. The one or more gain units may include one or more controllable gain units whereby blocking the input to the one or more gain units may include shutting off the one or more controllable gain units. The one or more gain units may further include one or more ASE-generating units configured to enable the line amplifier to operate in the ASE mode. For example, operating in the ASE mode may include a step of providing a power level below a fiber damage threshold level and above a level configured to enable detection of back-reflection at an output of the line amplifier. 
     Therefore, the systems and methods of the present disclosure may provide a number of advantages over conventional methods of powering up an amplifier, particularly after the amplifier has been newly installed in an optical line. For example, one advantage may be realized whereby a high isolation switch or blocker prevents any incoming light while the amplifier is in an ASE generation mode. That, in turn, prevents any possibility of Q-switching impact that can possibly damage immediate downstream connectors. Q-switching, for example, causes a short giant pulse from amplifier when light shows up at input at ASE generation process. 
     Also, the embodiments of the present disclosure allow installers to make a worry-free installation and can reduce the number of re-visits to the installation sites. Instead of requiring the installers to test the installations, the present disclosure provides embodiments whereby, as soon as the optical amplifier card is powered up, it can be automatically checked for back reflection that can be used to guarantee output fiber connectivity. 
     Another advantage is that the systems and methods described herein do not necessarily require a full installation or commissioning of a controller module since the bootstrap process is effectively governed by the control software/firmware on the card or from a local supervisory device. Without a controller module, it is even possible for the card to visually indicate the back-reflection status for the corresponding output port (e.g., by lighting up an LED indicator for high vs low reflection). 
     The present embodiments also allow installers to verify connectivity in both directions locally during their first installation attempt without disrupting any fiber plants (e.g., no disconnecting and reconnecting procedures) or without worrying about controller module installation or commissioning processes. Although the additional hardware controller (e.g., on-board controller  80 ) on the amplifier card may cost a little more, the benefit is that it can effectively reduce the number of truck-rolls and save installers from the need to return to the installation site for second or subsequent visits to the site. Thus, there would likely be a substantial savings in operating expenses for vendors who may be willing to pay the extra cost for the value derived from controlling installation procedures as described herein. 
       FIG.  13    illustrates that any amplifier including amplifiers at the channel-mux and channel demux can be put into an ASE generation mode for validation fiber connectivity. That is, while the present disclosure makes reference to line amplifiers, the techniques described herein can be implemented at any optical amplifier in an optical line system, including optical amplifiers at ROADM sites as illustrated in  FIG.  13   . 
     Although the present disclosure has been illustrated and described herein with reference to exemplary embodiments providing various advantages, it will be readily apparent to those of ordinary skill in the art that other embodiments may perform similar functions, achieve like results, and/or provide other advantages. Modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the spirit and scope of the present disclosure. All equivalent or alternative embodiments that fall within the spirit and scope of the present disclosure are contemplated thereby and are intended to be covered by the following claims.