WO2005102014A2 - Bloqueur de tonalites idler - Google Patents

Bloqueur de tonalites idler Download PDF

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Publication number
WO2005102014A2
WO2005102014A2 PCT/US2005/013717 US2005013717W WO2005102014A2 WO 2005102014 A2 WO2005102014 A2 WO 2005102014A2 US 2005013717 W US2005013717 W US 2005013717W WO 2005102014 A2 WO2005102014 A2 WO 2005102014A2
Authority
WO
WIPO (PCT)
Prior art keywords
optical
filters
idler
signal
line interface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2005/013717
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English (en)
Other versions
WO2005102014A3 (fr
Inventor
Stephen G. Evangelides, Jr.
Michael J. Neubelt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Red Sky Systems Inc
Original Assignee
Red Sky Systems Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Red Sky Systems Inc filed Critical Red Sky Systems Inc
Publication of WO2005102014A2 publication Critical patent/WO2005102014A2/fr
Anticipated expiration legal-status Critical
Publication of WO2005102014A3 publication Critical patent/WO2005102014A3/fr
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29392—Controlling dispersion
    • G02B6/29394—Compensating wavelength dispersion
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/27—Optical coupling means with polarisation selective and adjusting means
    • G02B6/2753—Optical coupling means with polarisation selective and adjusting means characterised by their function or use, i.e. of the complete device
    • G02B6/278—Controlling polarisation mode dispersion [PMD], e.g. PMD compensation or emulation
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
    • G02B6/29305—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
    • G02B6/2931—Diffractive element operating in reflection
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
    • G02B6/29316—Light guides comprising a diffractive element, e.g. grating in or on the light guide such that diffracted light is confined in the light guide
    • G02B6/29317—Light guides of the optical fibre type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G02B6/29382—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM including at least adding or dropping a signal, i.e. passing the majority of signals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29389—Bandpass filtering, e.g. 1x1 device rejecting or passing certain wavelengths
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29395—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device configurable, e.g. tunable or reconfigurable
    • 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
    • H04J14/0202—Arrangements therefor
    • H04J14/0206—Express channels arrangements

Definitions

  • the present invention relates generally to WDM optical transmission systems, and more particularly to an optical interface for providing communication between terrestrial optical terminal equipment and an undersea optical transmission path.
  • WDM and DWDM systems employ signals consisting of a number of different wavelength optical signals, known as carrier signals or channels, to transmit information on optical fibers. Each carrier signal is modulated by one or more information signals. As a result, a significant number of information signals may be transmitted over a single optical fiber using WDM and DWDM technology.
  • WDM and DWDM technology when the optical signals are transmitted over long distances, periodic amplification of the optical signals is necessary.
  • amplification is accomplished by using optical amplifiers, e.g. Erbium Doped Fiber Amplifiers (EDFAs) or Raman amplifiers.
  • EDFAs Erbium Doped Fiber Amplifiers
  • Raman amplifiers Raman amplifiers.
  • Optical amplifiers have the advantage of being relatively low in cost while being able to amplify all wavelengths without the need for demultiplexing and optoelectronic regeneration.
  • WDM systems currently under development are anticipated to have thirty or more channels, i.e., modulated optical signals with different wavelengths.
  • These WDM systems place stringent demands on the optical amplifiers that are employed, especially when two or much such amplifiers are distributed along the transmission path of the WDM system, resulting in only very limited tolerances in certain parameters.
  • gain flatness and gain tilt are of special importance.
  • Gain tilt arises when there are dynamic changes in operating conditions such as the input power and wavelengths of the transmitted channels. For example, when a channel is added or subtracted, thus changing the input power and spectrum of the optical signal, a gain fluctuation occurs that depends on the channel's wavelength, effectively "tilting" the gain of the amplifier.
  • WDM systems are often initially deployed at less than their maximum capacity. That is, a system designed to transmit 30 channels or more, for instance, initially may be more lightly loaded with only 2, 4, or 8 channels. Since the power and wavelength distribution of the optical signal will vary as the system is upgraded to increase its channel capacity, a problem arises when a system designed for a given capacity is operated at less than that capacity. This problem occurs because, as mentioned, the changes in power and wavelength distribution of the optical signal give rise to variations in gain flatness and gain tilt, which are undesirable because the system is generally designed to operate with a specific degree of gain flatness and a particular gain tilt.
  • idler channels are sometimes inserted along with the data-carrying channels.
  • the idler channels are often provided as unmodulated or cw tones. As the WDM system is upgraded, idler channels can be removed and replaced with data-carrying channels.
  • One type of highly specialized optical WDM system is an undersea or submarine optical transmission system in which a cable containing optical fibers is installed on the ocean floor.
  • the design of such optical transmission systems is generally customized on a system-by-system basis and employ highly specialized terminals to transmit data over the undersea optical transmission path. Since the specialized terminals are produced in small volumes they are relatively expensive in comparison to the optical terminals that are designed to communicate over terrestrial optical layer protocols, which are typically produced in relatively high volume for terrestrial optical transmission networks.
  • U.S. Appl. Serial No. 10/621,028 discloses an undersea optical WDM system in which the highly specialized terminals are replaced with less expensive, readily available terrestrial optical terminals that communicate with the undersea transmission path, which is often referred to as the "wet plant.”
  • An optical line interface (OLI) is provided between each terminal and the wet plant so that the wet plant is transparent to the terminals.
  • the OLI provides high compatibility between the proprietary interface of terrestrial optical terminals available from multiple vendors and the wet plant. That is, the OLI is designed to be terminal independent and serves as an interface between terrestrial optical layer transport protocols and an undersea optical layer transport protocol.
  • the terrestrial optical transmission equipment performs any necessary optical-to-electrical conversion, FEC processing, electrical-to-optical conversion, and optical multiplexing.
  • the terrestrial optical transmission equipment may also perform optical amplification, optical monitoring that is designed for the terrestrial optical network, and network protection.
  • the optical line interface in turn provides the signal conditioning necessary to transmit the traffic over an undersea optical transmission cable.
  • the optical line interface receives the optical signals from the terrestrial optical transmission equipment either as individual wavelengths on separate fibers or as a WDM signal on a single fiber.
  • the interface device provides the optical layer signal conditioning that is not provided by the terrestrial equipment, but which is necessary to transmit the optical signals over the undersea transmission path.
  • the signal conditioning that is provided may include, but is not limited to, gain equalization, bulk dispersion compensation, optical amplification, multiplexing, Raman amplification, dispersion slope compensation, polarization mode dispersion (PMD) compensation, performance monitoring, signal load balancing (e.g., idler channel insertion), or any combination thereof.
  • the optical line interface may also include line monitoring equipment such as a COTDR arrangement, an autocorrelation arrangement, or other techniques that uses in-band or out-of band probe signals to determine the status and health of the transmission path. Additionally, the optical line interface may supply pump power to the transmission path so that Raman amplification can be imparted to the optical signals.
  • an optical line interface for communicating between terrestrial terminal equipment and an undersea optical transmission path a WDM optical signal having a plurality of wavelength components.
  • the optical line interface includes a signal processing unit for transforming WDM optical signals between optical layer transport protocols employed by the terrestrial terminal equipment and undersea optical layer transport protocols employed over the undersea optical transmission path.
  • the optical line interface also includes an idler tone generator for generating idler tones at wavelengths corresponding to selected wavelengths components of the WDM signal that are not information-carrying wavelength components.
  • An idler tone blocker is located within a signal path of the signal processing unit for selectively transmitting and blocking wavelength components of the WDM optical signal corresponding to the idler tones.
  • the idler tone blocker includes a first plurality of narrow band filters each having an input port, a reflection port, and a transmission port. Each filter has a transmission band corresponding to a different one of the wavelength components of the WDM optical signal.
  • the reflection port of a first of the first plurality of filters is optically coupled to the input port of a second of the first plurality of filters.
  • a second plurality of narrow band filters each having an input port, a reflection port, and a transmission port each have a transmission band corresponding to a different one of the wavelength components of the WDM optical signal.
  • the reflection port of a first of the second plurality of filters is optically coupled to the input port of a second of the second plurality of filters.
  • a plurality of lxl optical switches each have an input coupled to a transmission port of a different one of the filters in the first plurality of filters and an output coupled to the transmission port of a filter in the second plurality of filters.
  • the filters in the first and second plurality of filters that have transmission ports optically coupled to one another by one of the switches have the same transmission band.
  • At least one of the narrow band filters comprises a fiber Bragg grating.
  • At least one of the narrow band filters comprises a multilayer dielectric thin film.
  • the idler tone blocker includes a first dispersive element for spatially displacing each of the wavelength components of the WDM signal with respect to one another.
  • the idler tone blocker also includes a spatial modulator for selectively transmitting and blocking each of the spatially displaced wavelength components.
  • a second dispersive element is provided for spatially recombining those wavelength components received from the spatial modulator.
  • At least one of the first and second dispersive elements is a grating.
  • the grating is selected from the group consisting of a blazed fiber grating, a ruled grating, a holographic grating, and an arrayed waveguide router.
  • the spatial modulator is selected from the group consisting of a liquid crystal cell array, a MEMs based shutter arrangement, and a MEMs based mirror arrangement.
  • the signal processing unit is configured to perform at least one signal conditioning process selected from the group consisting of gain equalization, bulk dispersion compensation, optical amplification,
  • Raman amplification Raman amplification, dispersion slope compensation, PMD compensation, and performance monitoring.
  • FIG. 1 shows an undersea optical WDM transmission system that employs conventional terrestrial terminal equipment that operates independently of the wet plant.
  • FIG. 2 shows an exemplary spectrum across the bandwidth of the channel wavelengths employed in the WDM system.
  • FIGs. 3(a) and 3(b) show the functionality to be provided by an idler tone blocker 300 constructed in accordance with principles of the present invention.
  • FIGs. 4 and 5 show the functionality of a narrow band pass filter that may be employed in an idler tone blocker constructed in accordance with the principles of the present invention.
  • FIG. 6 shows one embodiment of an idler tone blocker constructed in accordance with the principles of the present invention.
  • FIG. 7 shows an alternative embodiment of the inventive idler tone blocker.
  • FIG. 8 shows a block diagram of one embodiment of an optical line interface in which the present invention can be employed.
  • FIG. 1 shows an undersea optical WDM transmission system that employs conventional terrestrial terminal equipment that operates independently of the wet plant.
  • Terminal equipment 100i and 100 2 communicate with one another over wet plant 140 in a transparent manner via optical line interfaces (OLIs) 130 ⁇ and 130 2 , respectively.
  • Optical line interface may be of the type described in U.S. Appl. Serial No. 10/621,028, filed July 16, 2003.
  • the present invention encompasses other OLIs that provide transparency between the terminal equipment and the wet plant.
  • OLIs 130 ⁇ and 130 2 generate idler tones at unused channel wavelengths.
  • idler tones serve to increase the total optical power into the amplifiers to that of a fully loaded system in which all channel wavelengths are used to transmit information.
  • FIG. 2 shows an exemplary spectrum across the bandwidth of the channel wavelengths employed in the WDM system. As shown, idler tones are periodically spaced across the bandwidth. In order to maintain transparency between the terminal equipment and the wet plant, the idler tones added by each of the OLIs 130 ⁇ and 130 2 on their transmit sides must remove on their receive sides the idler tones generated by the other OLI so that the idler tones do not reach the terminal equipment 100 ⁇ and IOQ2.
  • FIGs. 3(a) and 3(b) show the functionality to be provided by an idler tone blocker 300 constructed in accordance with the present invention, which can be incorporated into the OLIs 130 ⁇ and 130 2 shown in FIG. 1.
  • a WDM signal directed to the input of the idler tone blocker 300 has channel wavelengths ⁇ i, ⁇ 8 , ⁇ 5 , ⁇ 2 and ⁇ 29 that are depicted as idler tones.
  • the idler tone blocker 300 removes the idler tones so that they do not appear at its output.
  • the idler tone blocker 300 must transmit those signal channels that it previously blocked. That is, the idler tone blocker 300 must be able to block an idler tone at a given wavelength and then at a later time transmit signals at that same wavelength.
  • FIG. 3(b) for example, a number of signal channels have been added to the WDM signal shown in FIG. 3(a), including at wavelengths ⁇ 5 and ⁇ 2 , which in FIG. 3(a) were idler tone channels.
  • the idler tone blocker 300 allows all signal wavelengths to appear on its output, which now includes wavelengths ⁇ 5 and ⁇ 2 that were previously blocked.
  • the idler tone blocker 300 comprises narrow band filters and a series of lxl optical switches.
  • the filters are three port devices designed in accordance with well-known principles to transmit one particular wavelength and reflect all others. As illustrated in FIGs. 4 and 5, each filter can operate in a reciprocal manner so that the transmitted wavelength may be added or dropped from the WDM signal.
  • the narrow band filters may be, for example, filter Bragg gratings or multilayer dielectric thin films.
  • FIG. 4 and 5 show the functionality of such a filter when used in a drop mode (FIG. 4) and an add mode (FIG. 5).
  • a WDM signal comprising wavelengths ⁇ i , ⁇ 2 , ... ⁇ n is directed along input port 410 of filter 400.
  • the filter 400 transmits a particular wavelength, in this case ⁇ i, to the transmission port 430 and reflects the remaining wavelengths to the reflection port 420. That is, the wavelength ⁇ i is dropped to the transmission port 430.
  • a WDM signal comprising wavelengths ⁇ 2 , ⁇ 3 , ... ⁇ n is directed along input port 510 of filter 500.
  • the wavelength ⁇ i is added along the transmission port 530 so that the wavelengths ⁇ i, ⁇ 2 , ⁇ 3 , ... ⁇ n appear on the reflection port 520. It should be emphasized that the filters 400 and 500 are identical to one another, only the manner in which the wavelengths are directed to them differ.
  • the filter shown in FIGs. 4 and 5 transmits a wavelength ⁇ i
  • other filters may be configured to transmit other wavelengths.
  • the idler tone blocker employs a series of filters that each transmit a successive wavelength with respect to one another
  • FIG. 6 shows one embodiment of the idler tone blocker 600 that employs the narrow band pass filters shown in FIGs. 4 and 5.
  • the idler tone blocker 600 comprises a first series of filters 610 ⁇ , 610 2 , 610 3 , ... 610 n , where n is equal to the number of channels in the WDM signal. In the particular example depicted in FIG. 6, n is equal to 8.
  • the idler tone blocker 600 also comprises a second series of filters 620 ⁇ , 620 2 , 620 3 , ... 620 n .
  • Each filter 610 drops a wavelength ⁇ j on its transmission port.
  • each filter 620i adds a wavelength ⁇ j on its transmission port.
  • filter 610j is the same as filter 620,. and thus the first series of filters are the same as the second series of filters.
  • the reflection port 604, of filter 610i is optically coupled to the input port 602j + ⁇ of filter 610j + ⁇ .
  • its input port 602 1 serves as the input port on which the WDM signal is received.
  • its reflection port 604 8 is optically coupled to the input port 622 ⁇ of filter 620 ⁇ in the second series of filters.
  • the transmission port 606j of each filter 610j in the first series of filters is coupled to the input port of a lxl optical switch 630j.
  • the filters 620 in the second series of filters are interconnected with one another in the same manner as the filters 610 in the first series of filters. That is, the reflection port 624; of filter 620j is optically coupled to the input port 622j + ⁇ of filter 620j + ⁇ . In the case of the final filter 620 8 , its reflection port 624 8 serves as the output port from the idler tone blocker 600.
  • the transmission port 626j of each filter 620j in the second series of filters is coupled to the output port of the lxl optical switch 630j.
  • each filter 610j drops the wavelength ⁇ ; to its transmission port 606, and transfers the remaining wavelengths from its reflection port 6041 to the input port 602j ⁇ f the filter 610j + ⁇ .
  • filter 610 ⁇ drops wavelength ⁇ i to its transmission port 606] and transfers wavelengths ⁇ 2 , ⁇ 3 , ... ⁇ 8 from its reflection port 604 ⁇ to the input port 602 2 of filter 610 2 .
  • filter 610 2 drops wavelength ⁇ 2 to its transmission port 606 2 and transfers wavelengths ⁇ 3 , ⁇ 4 , ... ⁇ 8 from its reflection port 604 2 to the input port 602 3 of filter 610 3 .
  • signal wavelengths ⁇ 4 , ⁇ s, ⁇ 6 , and ⁇ 7 are directed to the transmission port of the filters 620 4 , 620 5 , 620 6 , and 620 7 , respectively.
  • the signal wavelengths are then directed by their respective filters from the transmission port to the reflection port, which then communicates the signal wavelengths to the input port of the successive filter. In this way the signal wavelengths propagate through the second series of filters 620 and finally appear on the reflection port 624 8 of the final filter 620 8 .
  • the filters 610 and 620 have some net loss for both the transmitted and reflected signals, the accumulated losses on the dropped wavelengths are balanced by arranging the filters so that the first wavelength dropped in the first series of filters is also the first wavelength added in the second series of filters. Likewise, the second wavelength dropped in the first series of filters should also be the second wavelength added in the second series of filters.
  • FIG. 7 shows one alternative embodiment of the inventive idler tone blocker that employs a free space dispersive arrangement to selectively transmit and block the idler tones.
  • a first dispersive element 710 disperses the spectrum of the incoming WDM signal in free space.
  • the dispersive element 710 may be a grating such as a blazed fiber grating, a ruled grating, a holographic grating, or an arrayed waveguide router, for example.
  • the first dispersive element 710 spatially displaces the different wavelengths.
  • a spatial modulator 730 is located within the beam path of the spatially displaced wavelengths that can selectively transmit or block any desired wavelength or wavelengths.
  • the spatial modulator 730 is formed from a series of apertures, one for each wavelength.
  • the spatial modulator can encompass any appropriate arrangement including, but not limited to, a liquid crystal cell array, a MEMs based shutter arrangement, and a MEMs based mirror arrangement.
  • Those wavelengths that traverse the spatial modulator 730 will be reflected off a second dispersive element 720 that spatially recombines the wavelengths so that the resulting signal can be directed to the output port of the idler tone blocker.
  • FIG. 8 shows a block diagram of one embodiment of an optical line interface 800 in which the present invention can be employed.
  • the optical signal received from the terminal equipment is monitored for optical performance by optical performance monitor 802, then optically amplified by amplifier 806, and passed through a dispersion compensation device 808 such as a dispersion compensating fiber or a grating-based dispersion compensation device, after which the optical signal is ready to traverse the undersea optical transmission path.
  • a dispersion compensation device 808 such as a dispersion compensating fiber or a grating-based dispersion compensation device, after which the optical signal is ready to traverse the undersea optical transmission path.
  • the optical signal received by the interface device 800 from the undersea optical transmission path is optically amplified by amplifier 810, passed through a dispersion compensation device 812, and monitored for performance by optical performance monitor 818.
  • Optical performance monitors 802 and 818 monitor signal quality between the terminal equipment and the optical line interface 800. In some cases the optical performance monitors 802 and 818 may also monitor the health and status of the wet plant.
  • Idler tone generator 820 generates idler tones that are coupled with the optical signal received from the terminal equipment for transmission along the wet plant.
  • Idler tone blocker 822 is located in the transmission path of the optical line interface 800 that receives optical signals from the wet plant and forwards them to the terminal equipment. In FIG. 8 the idler tone blocker 822 is located between dispersion compensator 812 and the optical performance monitor 818. However, the idler tone blocker 822 may be situated at other points along the path that returns the optical signals to the terminal equipment. For example, idler tone blocker 822 may be located downstream from the optical performance monitor 818.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

Cette invention se rapporte à une interface des ligne optique servant à faire communiquer entre un équipement terminal terrestre et un canal de transmission optique sous-marin un signal optique WDM ayant plusieurs composantes de longueurs d'ondes. Cette interface de lignes optique comprend une unité de traitement de signaux servant à transformer les signaux optiques WDM entre des protocoles de transport de couche optique utilisés par l'équipement terminal terrestre et des protocoles de transport de couche optique utilisés sur le canal de transmission optique sous-marin. Cette interface de ligne optique comprend également un générateur de tonalités idler destiné à produire des tonalités idler aux longueurs d'onde correspondant aux composantes de longueurs d'ondes sélectionnées du signal WDM qui ne sont pas des composantes de longueurs d'ondes porteuses d'informations. Un bloqueur de tonalités idler est placé dans le canal des signaux de l'unité de traitement de signaux pour transmettre et bloquer sélectivement les composantes de longueurs d'ondes du signal optique WDM correspondant aux tonalités idler.
PCT/US2005/013717 2004-04-23 2005-04-22 Bloqueur de tonalites idler Ceased WO2005102014A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US83133604A 2004-04-23 2004-04-23
US10/831,336 2004-04-23

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WO2005102014A2 true WO2005102014A2 (fr) 2005-11-03
WO2005102014A3 WO2005102014A3 (fr) 2007-05-18

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006132927A3 (fr) * 2005-06-03 2007-12-27 Red Sky Subsea Ltd Traducteur de canal superviseur optique
WO2019179320A1 (fr) * 2018-03-20 2019-09-26 Huawei Technologies Co., Ltd. Procédé et système de commande de remplacement de canal et d'occupation spectrale

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Publication number Priority date Publication date Assignee Title
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US6704511B1 (en) * 2000-03-27 2004-03-09 Tyco Telecommunications (Us) Inc. Optical fiber transmission system with noise loaded idler channels
JP4495388B2 (ja) * 2002-04-01 2010-07-07 富士通株式会社 波長多重伝送システムにおける信号伝送方法並びに波長多重伝送システムに使用される波長多重送信装置，光分岐／挿入装置及び伝送装置

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WO2006132927A3 (fr) * 2005-06-03 2007-12-27 Red Sky Subsea Ltd Traducteur de canal superviseur optique
WO2019179320A1 (fr) * 2018-03-20 2019-09-26 Huawei Technologies Co., Ltd. Procédé et système de commande de remplacement de canal et d'occupation spectrale
US10530516B2 (en) 2018-03-20 2020-01-07 Huawei Technologies Co., Ltd. Method and system for controlling channel replacement and spectral occupancy

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