WO2002091027A2 - Procede et systeme de regulation de puissance d'amplificateur dans un reseau de communication optique dote d'une fonction d'insertion-extraction - Google Patents

Procede et systeme de regulation de puissance d'amplificateur dans un reseau de communication optique dote d'une fonction d'insertion-extraction Download PDF

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WO2002091027A2
WO2002091027A2 PCT/US2002/014183 US0214183W WO02091027A2 WO 2002091027 A2 WO2002091027 A2 WO 2002091027A2 US 0214183 W US0214183 W US 0214183W WO 02091027 A2 WO02091027 A2 WO 02091027A2
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Prior art keywords
amplifier
output power
determining
signal
composite
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WO2002091027A3 (fr
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James E. Degrange, Jr.
Sridhar Balakrishnan
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Ciena Corp
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Ciena Corp
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Priority claimed from US09/917,042 external-priority patent/US6600596B2/en
Priority claimed from US09/916,859 external-priority patent/US6614589B2/en
Application filed by Ciena Corp filed Critical Ciena Corp
Priority to AU2002340763A priority Critical patent/AU2002340763A1/en
Publication of WO2002091027A2 publication Critical patent/WO2002091027A2/fr
Anticipated expiration legal-status Critical
Publication of WO2002091027A3 publication Critical patent/WO2002091027A3/fr
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/29—Repeaters
    • H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
    • H04B10/293—Signal power control
    • H04B10/2933—Signal power control considering the whole optical path
    • H04B10/2935—Signal power control considering the whole optical path with a cascade of amplifiers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0221—Power control, e.g. to keep the total optical power constant
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H04B10/0775—Performance monitoring and measurement of transmission parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation

Definitions

  • the invention relates generally to a method and system for controlling amplifier power in an optical communications network.
  • Wavelength division multiplexing has been used to increase the capacity of existing fiber optic networks.
  • WDM Wavelength division multiplexing
  • Such systems typically include a plurality of receivers, each detecting a respective channel by effectively filtering out the remaining channels.
  • Optical channels in a WDM system are frequently transmitted over silica based optical fibers, which typically have relatively low loss at wavelengths within a range of 1525 nm to 1580 nm.
  • WDM optical signal channels at wavelengths within this low loss "window" can be transmitted over distances of approximately 50 km without significant attenuation. For distances beyond 50 km, however, optical amplifiers are used to compensate for optical fiber loss.
  • Optical amplifiers have been developed which include an optical fiber doped with erbium known as erbium-doped fiber amplifiers or EDFAs.
  • the erbium-doped fiber is "pumped" with light at a selected wavelength, e.g., 980 nm, to provide amplification or gain at wavelengths within the low loss window of the optical fiber.
  • Other types of optical amplifiers include erbium-doped waveguide amplifiers (EDWA), semiconductor optical amplifiers (SO A).
  • FIG. 1 is a block diagram of a conventional optical communications network having a plurality of amplifiers 10 l5 10 2 and 10 3 positioned along transmission fiber 12], 12 2 and 12 3 .
  • the output of each amplifier includes noise in the form of amplified spontaneous emissions (ASE) and at least one signal as shown in FIG. 1.
  • ASE amplified spontaneous emissions
  • the ASE increases due to the amplification of ASE input to the amplifier and ASE added at the amplifier. If, however, the output power of the amplifiers 10 l5 10 and 10 3 are equal, then the signal component is decreased to accommodate for the increase in ASE. For example, if the total output power of each amplifier is 8mw, the power available for the signal is reduced as the ASE power increases from one amplifier to the next. As shown in FIG. 1, setting the output power of each amplifier equal results in a decreased signal-to-noise ratio (SNR) as the signal passes through multiple amplifiers.
  • SNR signal-to-noise ratio
  • FIG. 1 is a block diagram of a portion of a conventional optical communications network
  • FIG. 2 is a block diagram of a portion of an optical communications network in an embodiment of the invention.
  • FIG. 3 is a block diagram of a portion of an optical communications network in an alternate embodiment of the invention.
  • FIG. 4 depicts the effect of adding and dropping channels along the optical communications network
  • FIGs. 5A and 5B illustrate two different techniques for dropping channels
  • FIG. 6 is a flowchart of a method of controlling amplifier power in a first embodiment of the invention.
  • FIG. 7 is a flowchart of a method of controlling amplifier power in a second embodiment of the invention.
  • FIG. 8 is a flowchart of a method of determining channel power in an exemplary embodiment of the invention.
  • the invention includes a method for controlling amplifier output power in an optical communications network having channel add/drop capability.
  • a first transmission parameter and a second transmission parameter are determined at a first amplifier.
  • the first transmission parameter is a composite express signal-to- noise ratio and the second transmission parameter is a composite signal-to-noise ratio.
  • the total output power of a downstream amplifier is adjusted in response to the first transmission parameter and second transmission parameter.
  • a system for implementing the method is also disclosed.
  • the invention includes a method for controlling amplifier output power in an optical communications network.
  • a first transmission parameter is determined at a first amplifier.
  • the first transmission parameter is a composite express signal to noise ratio.
  • the total output power of a downstream amplifier is adjusted in response to the first transmission parameter.
  • a system for implementing the method is also disclosed.
  • optical communicates refers to any connection, coupling, link or the like by which optical signals carried by one optical system element are imparted to the "communicating” element. Such “optically communicating” devices are not necessarily directly connected to one another and may be separated by intermediate optical components or devices. Likewise, the expressions “connection” and “operative connection” as used herein are relative terms and do not require a direct physical connection.
  • FIG. 2 is a block diagram of a portion of an optical communications network in an embodiment of the invention.
  • the optical communications network provides communications between transmitter 80 and receiver 82.
  • the optical communications system is a WDM system in which the transmitter 80 generates a plurality of signals, each on a separate wavelength or channel.
  • Receiver 82 detects the individual channels as known in the art.
  • the optical communications network includes a number of amplifiers 50 l5 50 2 and 50 3 which may be implemented using EDFAs.
  • the amplifiers 50 serve as signal regeneration points along sections of transmission fiber 52 ⁇ , 52 2 , 52 3 . It is understood that other components may be included in the transmission span such as switches, couplers, etc.
  • Each amplifier 50 is in communication with a communications device 62 and an associated node control processor (NCP) 64.
  • NCP 64 may be a microprocessor-based controller executing a computer program to determine the total output power for one or more amplifiers 50. It is understood that a one-to-one correspondence between amplifiers 50 and NCPs 64 is not required.
  • An NCP 64 may interface with a plurality of amplifiers 50 or a single master NCP may interface with all amplifiers.
  • the communications device 62 may be implemented using a service channel modem (SCM).
  • SCM service channel modem
  • Service channel modems may provide for communications between network elements as described in further detail in U.S. Patents 6,163,392, 5,978,115 and 5,532,864, the entire contents of which are incorporated herein by reference.
  • the NCPs 64 monitor transmission parameters at each amplifier 50 and communicate with amplifiers 50 and other NCPs 64 via communication devices 62.
  • the NCPs communicate over a service channel defined by one or more wavelengths (e.g., 1625 nm) carried on transmission fiber 52.
  • the communications devices 62 use this wavelength to communicate without interfering with the signals carried on separate wavelengths.
  • the NCPs may communicate over another communications network separate from transmission fiber 52.
  • the NCPs 64 adjust the output power at each amplifier 50 so that the SNR for each channel remains substantially constant over the entire transmission span.
  • Each NCP shares transmission parameters with other NCPs to adjust the output power at each amplifier.
  • each NCP 64 stores a network profile identifying the network elements in the transmission span. Thus, each NCP 64 knows its position in the communications network along with other transmission parameters such as the number of channels input and output at each amplifier, SNR at each amplifier, etc.
  • each NCP 64 adjusts the total output power of a corresponding amplifier 50 based on at least one transmission parameter obtained from an upstream amplifier.
  • upstream refers to a direction opposite the transmitter- receiver path.
  • downstream refers to a direction consistent with the transmitter- receiver path.
  • the NCP 64 determines the signal output power and the composite express output power. These values are used to determine the total output power for the amplifier.
  • the signal output power may be calculated based on channel count, channel plan information, and power adjustments (e.g., fiber type adjustment, user-defined power adjustment).
  • the composite express output power may be determined by the sum of the signal output power, the upstream ASE power and the current amplifier ASE power. Alternatively, one or both of the signal output power and the composite express output power can be measured.
  • a composite express signal-to-noise ratio may be calculated at each NCP 64 which is communicated to downstream NCPs (and optionally upstream and downstream NCPs) in the transmission span via communication devices 62.
  • the composite express signal-to-noise ratio at an amplifier output may be calculated by dividing the signal output power by the composite express output power.
  • the composite express output power may be calculated based on knowledge of the immediate upstream amplifier's composite express signal-to-noise ratio.
  • the upstream composite express signal-to-noise ratio may be defined as 1 for the first amplifier (e.g., amplifier 50 ⁇ ) in a transmission span.
  • a derivation of the calculation performed to determine the appropriate output power at an amplifier is provided below. The following variables are used in the derivation.
  • Pin j Total Input Power of amp j (not including power associated with communication device 62).
  • Pout,- Total Output Power at amp j (not including power associated with communication device 62).
  • Pout_express j Total Output Power at amp j assuming no blocks (not including power associated with communication device 62).
  • Psig_out j Composite Signal Output Power at amp j.
  • Snr_rati ⁇ j Ratio of the composite signal power to total output power at Amp j calculated as if there were no added/dropped channels in the transmission span.
  • Pase_expresSj Total ASE power at output of Amplifier j assuming no blocks Pas ⁇ j : Total ASE power at output of Amplifier j.
  • Padded_as ⁇ j Added ASE power at Amplifier j. This ratio may be defined at the output of the amplifier.
  • Equation (11) is used to determine the total output power Pout_express; for the i n amplifier so that the signal-to-noise ratio along the transmission span remains substantially constant. Equation (11) is derived as follows.
  • the signal output power is defined as shown in equation (1) where Padj; is a user-defined power adjustment factor for the 1 th amplifier.
  • the quantity linearValue(REFl) designates a signal output power based on a predetermined channel power multiplied by the number of output channels. In an exemplary embodiment, this value is 0.6 mw multiplied by the number of output channels.
  • the channels may be weighted to define channel units in which case the signal output power is the per channel unit power multiplied by the number of channel units. Defining channel power based on channel units provides more accurate power allocation. A channel is assigned a number of channel units based on transmission factors such as transmission rate and transmission format. The power allocated that channel is then determined based on the number of channel units.
  • the power adjustment value Padj is a user-defined power adjustment.
  • the amplifiers are specified to output the signal at some predefined level (e.g., -2dBm per channel).
  • the power adjustment value Padj allows the user to adjust this level.
  • the power adjustment value may be 1 dB causing the amplifier to output the signal at -ldBm per channel.
  • the total output power is represented as shown in equation (2). As can be seen, the total output power is a sum of the signal output power Psig_out;, ASE power from the preceding (i-l th ) amplifier which is amplified at the i l amplifier and any ASE power added at the i amplifier.
  • Pout_express; Psig_out; + Pase_expressi- ⁇ *(Gaini/Loss;) + Padded_ase;
  • the composite express signal-to-noise ratio may be defined as the ratio of output signal power to the total output power. Again, with reference to FIG. 2, it is assumed that no add/drop multiplexers (ADMs) are located in the transmission span. This provides a direct measure of the added ASE power between two amplifiers in the transmission span.
  • the (Pase_expressi- ⁇ *(Gaini/LosSi)) term may be represented using the following:
  • Pase_expressj -1 Pout_expressi. ⁇ -
  • Gain; (Psig_out;/Nouti) / (Psig_inj/Ninj).
  • Pout_express Psig_outi/snr_rati ⁇ i -1 + Padded_ase; (11)
  • F as e(gain) is the ASE gain for the i th amplifier. This value may be retrieved from a table indexed by the per-channel gain as calculated by
  • Pir ent_vai measured input power level (current value) of amplifier i in mW
  • Nout; number of output channel at amplifier i.
  • the number of input channels equals the number of output channels at each amplifier along the transmission span.
  • each channel may be weighted to define channel units in which case the signal output power is the per channel unit power multiplied by the number of channel units. Defining channel power based on channel units provides more accurate power allocation.
  • the composite express signal-to-noise ratio from the i-l th amplifier is used to determine the output power for the i amplifier. It is understood that transmission parameters other than composite express signal-to-noise ratio may be used to determine the output power of downstream amplifiers. For example, the channel count N may be used by downstream amplifiers to establish the signal power.
  • the calculation of output power in equation (11) does not include power used to provide a service channel for the communications devices 62 if present on the transmission fiber 52.
  • This service channel for the communications devices 62 may be outside the amplification band of amplifiers 50 and thus is not included in equations (1)- (11).
  • An additional power offset (e.g., 2 w) may be added to the output power determined in equation (11) to provide for the service channel utilized by communications devices 62.
  • the service channel utilized by communications devices 62 is preferably an "out- of-band channel", meaning that this communications channel is distanced from the channels carrying the transmission signals.
  • the out-of-band service channel is 1625 nm. This wavelength is preferable because it is not affected by amplifiers 50 and may still be utilized even if amplifiers 50 are inoperative.
  • NCP 64 ⁇ sets the output power of amplifier 50 ⁇ based on equation (11). Because amplifier 50j is the first amplifier in the transmission span, the value of the upstream composite express signal-to-noise ratio (snr_rati ⁇ o) is set to 1. NCP 64 ⁇ determines the composite express signal-to-noise ratio (snr__ratioi) and broadcasts this transmission parameter to at least the immediate downstream NCP 64 2 , if not multiple upstream and downstream NCPs.
  • NCP 64 2 determines the appropriate output power based on equation (11).
  • the value for the composite express signal-to-noise ratio (snr_rati ⁇ ) has been received from NCP 64 ⁇ .
  • NCP 64 2 determines the composite express signal-to-noise ratio (snr_ratio 2 ) and broadcasts this value to at least the immediate downstream NCP 64 3 , if not all NCPs.
  • the output power of each successive amplifier is increased as the signal proceeds along the transmission span to maintain the signal-to-noise ratio for each channel substantially constant.
  • the first transmission parameter e.g., composite express signal-to-noise ratio
  • this transmission parameter is broadcast to other network elements at step 102.
  • signal output power for the second amplifier is determined and at step 106, amplified spontaneous emission generated at the second amplifier is determined.
  • the proper amount of output power for the second amplifier is determined at step 108 is response to the first transmission parameter, the signal output power for the second amplifier and amplified spontaneous emission generated at the second amplifier. This determined value is then used to control output power of the second amplifier at step 110.
  • the communication network has the ability to add and/or drop channels along the transmission span. This may be accomplished through an add/drop multiplexer 54 which may be implemented using an optical add/drop multiplexer (OADM). Alternatively, amplifiers 50 may include components to provide the add/drop function.
  • OADM optical add/drop multiplexer
  • the ASE may vary for each channel depending on whether the channel has been added or dropped and the type of drop.
  • a drop where a section of the bandwidth is attenuated (including ASE and signal) and thus prevented from continuing down the span is referred to as a block.
  • Such a block may be accomplished through gratings, filters, etc.
  • the block substantially eliminates all power (ASE, signal, etc) for a section of bandwidth downstream of the OADM.
  • the degree of attenuation is limited by the efficiency of the component performing the block.
  • FIG. 3 depicts a single signal being carried on one channel.
  • the signal and ASE are depicted below each corresponding amplifier 50.
  • the signal is blocked (e.g., delivered to a recipient) and a new signal is added on the same channel.
  • the ASE associated with the newly added signal is zero.
  • the determination of amplifier output power will vary based on whether and where in the transmission span channels were added and/or blocked.
  • the block-type drop is contrasted with a drop-and-continue.
  • a drop-and- continue is performed, the signal and ASE are dropped from a first transmission path and routed to a second transmission path without attenuation.
  • the downstream amplifier in the second transmission path does not need to compensate for a reduction in ASE.
  • the NCPs adjust output power of a respective amplifier to accommodate for ASE power reduction due to blocked channels.
  • a downstream amplifier determines the amount of ASE blocked by upstream network elements. This determination may be performed by receiving transmission parameters (e.g., signal-to-noise values, channel counts, etc.) from upstream elements and determining the amount of ASE power blocked upstream. Alternatively, ASE power may be measured at points along the transmission path. Based on the amount of ASE power blocked upstream, the downstream amplifier output power is adjusted accordingly.
  • transmission parameters e.g., signal-to-noise values, channel counts, etc.
  • each NCP determines signal output power, composite express output power and composite output power. Alternatively, one or more of these powers may be measured.
  • the signal output power and composite express output power are determined as described above with reference to FIG. 2.
  • the composite output power is the amplifier output power taking into account the effects of ASE power being blocked by one or more ADMs upstream in the transmission span.
  • a composite express signal-to-noise ratio and a composite signal-to-noise ratio are determined.
  • the composite express signal-to-noise ratio (snr_ratio) is determined as described above with reference to FIG. 2.
  • the composite signal-to-noise ratio (sig_ratio) at an amplifier output is calculated by dividing the signal output power by the composite output power.
  • the composite express signal-to- noise ratio (snr_ratio) and the composite signal-to-noise ratio (sig_ratio) may be calculated at each NCP 64 and then communicated to downstream NCPs (and optionally all NCPs) in the transmission span.
  • each NCP 64 determines amplifier total output power based on the upstream amplifier's composite signal-to-noise ratio (sig_ratio) as well as the composite express signal-to-noise ratio (snrjratio) at all upstream amplifier's at ADM sites.
  • the upstream composite signal-to-noise ratio (sig_ratio) and the composite express signal-to-noise ratio (snrjratio) used by the first amplifier in a transmission span are implicitly defined as 1.
  • a derivation of the calculation performed to determine the total output power at an amplifier, including adjustments for adds/blocks, is provided below.
  • the following variable is used in the derivation.
  • Sigjratio j Ratio of Composite Output Signal Power to Total Output Power at Amp j. This ratio may be defined at the output of the amplifier.
  • Equation (22) is used to determine the proper signal output Pout; for the i th amplifier so that the signal-to-noise ratio for each channel along the transmission span remains substantially constant. Equation (22) is derived as follows. The output power at the i th amplifier is first established as shown in equations (12)-(14).
  • Pout; Psig_out; + Pasei. ⁇ *(Gaini/LosSj) + Padded_ase;. (14)
  • Pout; Psig_out; * (1 + (Nm;/Nouti) * (l/sig_rati ⁇ i- ⁇ - 1)) + Padded_asej. (18)
  • equation (18) is reduced to:
  • Pout; Psig_outi/sig_rati ⁇ i- ⁇ + Padded_ase;. (19)
  • Pout; Pouti - ⁇ C h (Pase_expressj. ⁇ * (Gainj/Lossi) - Pase_express k )*filt_bw Ch . (20)
  • Subscript ch designates each channel on the current amplifier that has been blocked.
  • Variable Pas ⁇ k is the total ASE power at the output of amplifier "k” which is the amplifier positioned after the first upstream element blocking channel ch.
  • the subscript "k” is used with variables corresponding to the first amplifier upstream of amplifier "i" where channel ch has been blocked. For example, referring to FIG. 4, amplifier “k” is amplifier 50 ⁇ which is positioned immediately after the first upstream element, ADM 54 1 ⁇ blocking channel ch.
  • Variable filt_bw c h is a variable dependent on the type of block used in the ADM.
  • Equation (20) allows the proper amount of ASE to be subtracted from the amplifier total output power.
  • Figure 4 depicts the subtraction of ASE provided by equation (20) for determining the output power at amplifier 50 3 .
  • a channel is blocked (e.g., delivered to a recipient) and added back in (e.g., a new signal is submitted) at ADM 54].
  • the ASE- for that channel substantially zero.
  • the ASE is increased for all channels, including the added channel.
  • ADM 54 3 the channel is again blocked and added to place the ASE power for that channel substantially equal to zero.
  • the output power of the amplifier 50 3 needs to be compensated to reflect the loss of ASE power for this channel between the output of amplifier 50 2 and the input of amplifier 50 3 .
  • equation (20) dictates that the amplified ASE power from the previous amplifier, Pase_expresSi- ⁇ * (Gain Loss;), is reduced by the ASE power at the first network element where the channel was blocked, Pase_express k . Relating to FIG. 4, this corresponds to subtracting the ASE power at amplifier 50 ⁇ from the ASE power at amplifier 50 2 . This determines the amount of ASE power (shown cross-hashed in FIG. 4) reduced through the block at ADM 54 3 .
  • the ASE power adjustment variable filt_bw c adjusts the amount of ASE power subtracted due to blocked channels.
  • the ASE power adjustment variable may take on different values depending on the type of channel block that is employed. As shown in FIG.
  • a first type of block used in the art is a channel-by-channel block. This type of block attenuates the signal and associated ASE in individually, spaced channels. Thus, some ASE power remains un-blocked between the blocked channels.
  • a second type of block is a band block in which an entire range of wavelengths is removed. As shown in FIG. 5B, all signals and all associated ASE within a band are removed.
  • the ASE power adjustment variable filt_bw Ch has a value smaller than if a band block is used. This is due to the fact that more ASE power should be subtracted when a band block is used.
  • the ASE power adjustment variable filt_bw c h is about .005 if a channel-by-channel block is used and about .010 if a band block is used. It is understood that other values may be used depending on a variety on network characteristics such as channel spacing, etc.
  • the number of signals can vary from one amplifier to the next given the add/drop functionality.
  • Noutk and Nout represent the number of channels output at the amplifier where the channel was first blocked and the current amplifier, respectively.
  • the number of channels may be represented as channel units to effectively weight the channels and accurately allocate power to each channel.
  • Padj k and Padj are user-defined power adjustment factors (e.g., measured in dB) for the amplifier where the channel was first blocked and the current amplifier, respectively.
  • the power at the i th amplifier is dependent on a first transmission parameter (composite signal-to-noise ratio sig_ratio) and a second transmission parameter (composite express signal-to-noise ratio snr atio) from the i-l th amplifier.
  • the output power at the X amplifier is also dependent on whether channels have been blocked along the transmission span and the type of block (band or channel) performed through ASE power adjustment variable filt_bw Ch .
  • the number of channels output at each amplifier is broadcast to the NCPs 64.
  • additional power e.g. 2 mw
  • this communications channel is an out-of-band channel as described above with reference to FIG. 2.
  • the first transmission parameter e.g., composite express signal-to-noise ratio
  • second transmission parameter e.g., composite express signal-to-noise ratio and composite signal-to-noise ratio
  • first transmission parameter e.g., composite express signal-to-noise ratio
  • second transmission parameter e.g., composite express signal-to-noise ratio and composite signal-to-noise ratio
  • signal output power for the second amplifier is determined and at step 206, amplified spontaneous emission generated at the second amplifier is determined.
  • the output power for the second amplifier is determined at step 208 is response to the first transmission parameter, the second transmission parameter, the signal output power for the second amplifier and amplified spontaneous emission generated at the second amplifier. This determined value is then used to control output power of the second amplifier at step 210.
  • the channel count variable N used in the above equations may be dependent upon transmission parameters such as transmission rate and transmission format of the signal.
  • a channel may be weighted as multiple channel units depending on transmission rate and transmission format.
  • FIG. 8 is a flowchart of a process for determining the number of channel units corresponding to channel. The method may be implemented by an NCP 64 in response to a computer program in a storage medium accessible by the NCP.
  • the process begins at step 300 where at least one transmission parameter is determined for a channel.
  • Transmission parameters may relate to transmission rate (e.g., bps) or transmission format (e.g., the use of forward error correction).
  • the number of channel units for the channel are determined. The determination of the number of channel units may be based on any number of transmission parameters.
  • the power for the channel is determined at step 304. The channel power may be determined based on the number of channel units multiplied by a power per channel unit value. The channel power can then be controlled as shown at step 306. In an exemplary embodiment, a signal having a transmission rate of 2.5 Gbps is weighted as 1 channel unit.
  • a signal having a 10 Gbps transmission rate using forward error correction is weighted as 2 channel units.
  • a signal having a 10 Gbps transmission rate without forward error correction is weighted as 4 channel units.
  • Table A below depicts exemplary channel units and the associated channel power for different transmission rates and transmission formats.
  • the variable x represents a power per channel unit value.
  • the processing performed to determine the total output power may be implemented by a microprocessor-based NCP.
  • the invention may be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention.
  • the computer program code segments configure the microprocessor to create specific logic circuits.

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  • Computer Networks & Wireless Communication (AREA)
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Abstract

L'invention concerne un procédé destiné à réguler une puissance de sortie d'amplificateur dans un réseau de communication optique doté d'une fonction d'insertion-extraction. Un premier paramètre de transmission et un second paramètre de transmission sont déterminés au niveau d'un premier amplificateur. Dans un mode de réalisation, le premier paramètre de transmission est un rapport signal sur bruit exprès composite, le second paramètre de transmission étant un rapport signal sur bruit composite. La puissance de sortie totale d'un amplificateur aval est ajustée en réponse au premier paramètre de transmission et au second paramètre de transmission. L'invention concerne également un système destiné à la mise en oeuvre de ce procédé.
PCT/US2002/014183 2001-05-09 2002-05-03 Procede et systeme de regulation de puissance d'amplificateur dans un reseau de communication optique dote d'une fonction d'insertion-extraction Ceased WO2002091027A2 (fr)

Priority Applications (1)

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AU2002340763A AU2002340763A1 (en) 2001-05-09 2002-05-03 Method and system for controlling amplifier power in an optical communications network having add/drop capability

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US28967201P 2001-05-09 2001-05-09
US60/289,672 2001-05-09
US09/917,042 US6600596B2 (en) 2001-05-09 2001-07-27 Method and system for controlling amplifier power in an optical communications network having add/drop capability
US09/916,859 US6614589B2 (en) 2001-05-09 2001-07-27 Method and system for controlling amplifier power in an optical communications network
US09/917,042 2001-07-27
US09/916,859 2001-07-27

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005041451A1 (fr) * 2003-10-25 2005-05-06 Marconi Communications Gmbh Reseau optique et noeud amplificateur associe
EP1439646A3 (fr) * 2003-01-14 2005-12-14 ECI Telecom Ltd. Technique de réglage de puissance dans des réseaux optiques

Family Cites Families (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5229876A (en) * 1990-03-26 1993-07-20 At&T Bell Laboratories Telemetry for optical fiber amplifier repeater
US5471334A (en) * 1992-10-21 1995-11-28 Nippon Telegraph And Telephone Corporation Method and apparatus for monitoring noise figure of optical amplifier
FR2703531B1 (fr) * 1993-03-30 1995-05-19 Cit Alcatel Dispositif d'évaluation de la qualité de transmission d'un équipement amplificateur optique.
GB2280560B (en) * 1993-07-31 1997-09-03 Northern Telecom Ltd Communications system
CA2155693C (fr) * 1994-08-25 1999-12-14 Daniel A. Fishman Methode et dispositif de controle de systemes de transmission optique et de localisation de defaillance
JP3306693B2 (ja) * 1995-01-19 2002-07-24 富士通株式会社 光増幅装置，光波長多重通信システム，光端局装置及び光中継装置
US5532864A (en) * 1995-06-01 1996-07-02 Ciena Corporation Optical monitoring channel for wavelength division multiplexed optical communication system
JPH0964819A (ja) * 1995-08-23 1997-03-07 Fujitsu Ltd 光システム
US5673129A (en) * 1996-02-23 1997-09-30 Ciena Corporation WDM optical communication systems with wavelength stabilized optical selectors
JPH09321701A (ja) * 1996-05-31 1997-12-12 Fujitsu Ltd 光通信システム及び光増幅器
JPH10229386A (ja) * 1997-02-17 1998-08-25 Nec Corp 光ファイバアンプとこれを用いた光通信システム
US6163392A (en) * 1997-05-23 2000-12-19 Ciena Corporation Distributed intelligence wavelength division multiplexed network
WO1998054863A1 (fr) * 1997-05-27 1998-12-03 Ciena Corporation Systeme de gestion d'une liaison destine a un reseau multiplexe en longueur d'onde
US5986782A (en) * 1997-05-29 1999-11-16 Ciena Corporation Signal-to-noise monitoring in WDM optical communication systems
US6344915B1 (en) * 1997-06-20 2002-02-05 Ciena Corporation System and method for shutting off an optical energy source in a communication system having optical amplifiers
JP3549716B2 (ja) * 1997-11-28 2004-08-04 日本電気株式会社 光ａｄｍ装置
US6115157A (en) * 1997-12-24 2000-09-05 Nortel Networks Corporation Methods for equalizing WDM systems
US6441955B1 (en) * 1998-02-27 2002-08-27 Fujitsu Limited Light wavelength-multiplexing systems
JPH11331127A (ja) * 1998-05-19 1999-11-30 Fujitsu Ltd 波長分割多重システム、及びその端局
US6163399A (en) * 1998-12-08 2000-12-19 Nortel Networks Limited Method and apparatus for suppressing transients in optical amplifiers
US6433903B1 (en) * 1999-12-29 2002-08-13 Sycamore Networks, Inc. Optical management channel for wavelength division multiplexed systems
US6313940B1 (en) * 1999-12-31 2001-11-06 Lucent Technologies Inc. System based control of optical amplifier transmission functions
US6421167B1 (en) * 2000-03-03 2002-07-16 General Dynamics Advanced Technology Systems, Inc. Multiple function bandwidth management systems
JP3242095B2 (ja) * 2000-05-16 2001-12-25 矢崎総業株式会社 ヒューズ
IT1320596B1 (it) * 2000-08-18 2003-12-10 Marconi Comm Spa Sistema di trasmissione ottico.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1439646A3 (fr) * 2003-01-14 2005-12-14 ECI Telecom Ltd. Technique de réglage de puissance dans des réseaux optiques
US7242864B2 (en) 2003-01-14 2007-07-10 Eci Telecom Ltd. Technique for power control in optical networks
WO2005041451A1 (fr) * 2003-10-25 2005-05-06 Marconi Communications Gmbh Reseau optique et noeud amplificateur associe
US7831148B2 (en) 2003-10-25 2010-11-09 Ericsson Ab Optical network and amplifier node therefore
CN1918829B (zh) * 2003-10-25 2010-12-29 爱立信股份有限公司 光网络和用于它的放大器节点

Also Published As

Publication number Publication date
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WO2002091027A3 (fr) 2009-06-11

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