Abstract: A method for bi-directionally transmitting digital optical signals over an optical transmission link in which a first optical transmit signal is created according to a first binary digital signal in such a way that the bit information of the first binary digital signal is included in first sections of the symbol interval of the first optical transmit signal. A second optical transmit signal is created by creating an optical wavelength reuse signal using the first optical transmit signal received at the second end of the optical transmission link, the optical wavelength reuse signal being modulated according to a second digital signal in such a way that the bit information of the second digital signal is included in second sections of the symbol interval of the first optical transmit signal received.

Abstract: An optical transmission system method including generating for a tunable laser a pilot tone having an adjustable pilot tone frequency identifying a wavelength division multiplexing channel used by the tunable laser; multiplying the pilot tone with pilot tone data to provide a pilot tone data signal; supplying the pilot tone data signal and a high frequency data signal to the tunable laser generating an optical laser signal output by the tunable laser responsive to the supplied signals; transporting the optical laser signal to a central wavelength to locker; converting the received optical laser signal to provide a pilot tone data signal for wavelength division multiplexing channels demodulated to detect the pilot tone and the pilot tone data for each individual wavelength division multiplexing channel; and identifying the wavelength division multiplexing channel on the basis of the pilot tone frequency of the detected pilot tone and evaluating the pilot tone data.

Abstract: A method for scaling traffic engineering, TE, routing in a network, having a plurality of network elements (nodes) connected in a given layer to each other via links TE domain segments of a TE domain of said network are collapsed into a virtual TE nodes (VNs). Each VN having an allocated DE domain unique identifier and a detailed connectivity matrix, DCM, to provide a hierarchically virtualized network topology of the network.

Abstract: Arrangement for transmitting an optical digital WDM signal over an optical transmission link or a passive optical network, the signal (SWDM) including N optical channels matching a given optical frequency grid. The scheme includes supplying the WDM signal (SWDM) to a near end of the optical transmission link or a near end of the passive optical network; receiving the WDM signal (SWDM) at a far end of the optical transmission link or at one or more far ends of the passive optical network; separating the optical channel signals (si(t)) by splitting and bandpass filtering the WDM signal (SWDM) received; and converting the optical channel signals (si(t)) into electrical channel signals using direct optical detection. The signal (SWDM) is created such that neighboring channel signals (si(t)) are orthogonally polarized and are conditioned with specific pre-distortion.

Abstract: A method for transmitting a binary digital transmit signal over an optical transmission link includes creating a differential optical duobinary signal, supplying the differential optical duobinary signal to a first end of the optical transmission link, transmitting the differential optical duobinary signal to a second end of the optical transmission link, and receiving the differential optical duobinary signal as a receive signal at the second end of the optical transmission link. The differential optical duobinary signal may be created by pre-coding the binary digital transmit signal having a given bit interval (T) in two pre-coding steps each with a signal delay of a single bit interval or in a single pre-coding step with a signal delay of twice the bit interval. In each case the pre-coding applies a non-XOR or equivalent operation.

Abstract: The invention relates to a method of operating a primary optical node, particularly an optical line terminal (OLT), for an optical communications system, wherein said OLT is configured to receive at least one upstream optical signal (uos) from at least one secondary optical node, particularly an optical networking unit (ONU), within at least a first wavelength range (wr1), and to transmit at least one downstream optical signal (dos) to said at least one ONU within at least a second wavelength range (wr2), wherein said OLT determines a currently unused wavelength subrange (wsr2) within said first wavelength range (wr1), assigns a specific target wavelength (?t) within said currently unused wavelength subrange (wsr2) to said ONU, signals said target wavelength (?t) to said ONU, receives an upstream signal (us) from said ONU, and provides feedback information to said ONU.

Abstract: An apparatus comprising high speed ports connected via an integrated high speed serial switch fabric and serializer/deserializer circuits to an internal processing logic, wherein said high speed serial switch fabric is adapted to switch a serial reception signal received by a high speed port to at least one other high speed port of said apparatus and/or to the serializer/deserializer circuit of the receiving high speed port.

Abstract: An optical frequency locking method tunes each of a plurality of narrow-band optical channel transmit signals (having arbitrary channel frequency spacings) to a dedicated optical channel frequency. The method includes tapping-off a portion of the optical power of the respective channel transmit signal and filtering the tapped-off channel transmit signal using at least one optical filter device. The method also includes monitoring, as an optical input signal, the optical power of the respective channel transmit signal supplied to the at least one optical filter device and, as an optical output signal, the optical power of the filtered channel transmit signal. The method further includes tuning, within a predetermined locking range for the dedicated optical channel frequency, the optical frequency of the respective channel transmit signal such that a predetermined value for the ratio of the output signal and the input signal is reached.

Abstract: A hybrid wavelength division multiplexing system wherein one or more intensity modulated signals generated by optical amplitude modulators are co-propagated with one or more phase modulated signals generated by optical phase modulators, wherein a drive voltage of said optical amplitude modulator is adapted to reduce an extinction ratio of the intensity modulated signal to minimize a cross-phase modulation impact on the co-propagating phase modulated signals.

Abstract: The invention relates to an optical network element, particularly an optical line terminal, OLT, for transmitting and receiving signals wire an optical network that comprises at least one optical fiber link and at least one further optical network element. The optical network element provides a primary optical pumping mean for emitting optical pump power to set at least one optical fiber link. The emitted optical pump power forms at least one gain medium outside the optical network element to provide optical pump power to the network for amplifying the singles to receive so that outside of the domain of the optical network element no electrical energy supply is needed.

Abstract: The invention relates to a method for monitoring a detachable fiber-optic connection, especially in a fiber-optic transmission device or system, comprising the steps of transmitting a wanted optical transmission signal carrying information data to be transmitted to at least one fiber-optic connection, a predetermined portion of the power of said optical transmission signal being reflected at the at least one fiber-optic connection depending on the status and properties of the at least one fiber-optic connection, creating a detection signal by detecting said reflected predetermined portion of the power of said optical transmission signal, monitoring and evaluating the detection signal as a function of time and creating a “DETECT” signal if the detection signal or a signal derived from the detection signal reveals a characteristic change in its course in time. Further, the invention relates to a corresponding device adapted to realize this method.

Abstract: The invention relates to a method for the transmission of a digital signal in inverse multiplexing, particularly via an Optical Transport Network (OTN), in which a digital signal to be transmitted, which is split into a certain number M of several sub-signals, where each sub-signal of a transmit side of a transmission line assigned exclusively to this sub-signal is transmitted to a reception side of the assigned transmission line, and in which, on the reception side of the transmission lines, the sub-signals are reassembled to a digital reception signal.

Abstract: A monitoring apparatus for detecting uncharacteristic short-term power level changes of an optical signal transmitted through an optical fiber, said monitoring apparatus comprising a power level variance calculation unit adapted to calculate a power level variance on the basis of a long-term power level and a current power level of said optical signal and a short-term variance filter adapted to filter transient changes indicated by the calculated power level variance and to generate a trouble occurrence indication indicating an uncharacteristic short-term power level change, if the filtered power level variance exceeds a predetermined power level variance.

Abstract: An optical line termination node has a first connection arrangement for connecting a working fiber, a second connection arrangement for connecting a protection fiber, a transceiver arrangement having first primary link and a first secondary link, and protection switching means configured for being switched either in a working operating state or in a protection operating state.

Abstract: The length of the optical fiber section under tension expands by a certain amount that is proportional to the level of tension applied to it. Monitoring the variations in the phase of the arriving signal allows to discover a fiber that is subject to a certain level of mechanical tension. With the method and apparatus according to the present invention it is possible to protect optical communication channels against failures in an optical transmission fiber that are caused by any kind of mechanical disturbances.

Abstract: A network with a network wide extended policy framework comprising: path computation clients (PCCs), associated with at least one local policy enforcement point (PEP); path computation servers (PCSs), associated with at least one policy decision point (PDP). The PEPs and PDPs adapted to exchange attributes determined by at least one PDP. PDPs are adapted to identify network elements/network services requiring identical configuration parameters by evaluating parameters advertised in the network and update policy related to identified groups in case of configuration error. Updated policy is distributed by PDP in policy notification to PEPs associated with network elements/network services of identified group. The PEPs receiving policy notification comprising updated policy from PDP adapted to translate the updated policy into configuration settings of network elements/network services the identified group.

Abstract: A network node of a synchronous network, wherein said network node comprises a timing circuit which recovers a reference clock from a reception signal received by said network node from an upstream network node of said synchronous network and uses the recovered reference clock for a transmission signal transmitted by said network node to a downstream network node of said synchronous network; and a clock stability monitoring circuit which monitors internal control parameters (CP) of said timing circuit to detect an instability of the reference clock distributed within said synchronous network.

Abstract: A holding device for holding cylindrical fiber optical components comprising at least one stackable body each having at least one recess adapted to receive cylindrical fiber optical components.

Abstract: An optical fiber transmission system adapted to provide a remote passive identification of components deployed in said transmission system, wherein each component comprises an associated passive optical identification unit adapted to provide identification of a component type of the respective component on the basis of a received optical identification signature carried in an optical identification signal to said component.

Abstract: Provided are systems and methods for adaptive, error-tolerant pattern recognition in the transmission of digital data packets, in which an actual data pattern, including several bits, is detected and is compared with a theoretical data pattern; erroneous and/or correctly recognized bits are detected; erroneous and/or correctly recognized bits are added up (in each case); and the error sum (number of the errors) of the added-up erroneous bits is compared with a specifiable and changeable admissible maximum number of errors.