Abstract: A method for controlling a laser profiler, the laser profiler being configured for generating a laser line on a surface to be inspected, the method comprising: receiving an image of the laser line; determining an actual intensity of the laser line; calculating an amplification factor for the laser line based on the actual intensity of the laser line, a target intensity for the laser line, a power of the laser, a camera gain of the camera and an exposure time of the laser line on the surface to be inspected, the amplification factor allowing the actual intensity of the laser line to reach the target intensity while minimizing the power of the laser; and based on the calculated amplification factor, adjusting at least one parameter of the laser profiler so that the actual intensity of the laser line corresponds to the target intensity.

Abstract: A method for controlling a laser profiler, the laser profiler being configured for generating a laser line on a surface to be inspected, the method comprising: receiving an image of the laser line; determining an actual intensity of the laser line; calculating an amplification factor for the laser line based on the actual intensity of the laser line, a target intensity for the laser line, a power of the laser, a camera gain of the camera and an exposure time of the laser line on the surface to be inspected, the amplification factor allowing the actual intensity of the laser line to reach the target intensity while minimizing the power of the laser; and based on the calculated amplification factor, adjusting at least one parameter of the laser profiler so that the actual intensity of the laser line corresponds to the target intensity.

Abstract: Measuring a distance to a surface while compensating for variations in a transverse position and/or low speed displacement of the instrument. One method includes retrieving a predetermined transversal distance from a longitudinal feature at which to extract a relevant distance; retrieving a distance set; retrieving a position of the longitudinal feature relative to the distance set; extracting a range point at the predetermined transversal distance from the longitudinal feature; adding the extracted point to a longitudinal distance set. In another method, if two sensors are provided with an overlap in the transversal direction, extracting a range point at a predetermined transversal position; adding the extracted range point to a longitudinal distance set; retrieving a pitch angle of the instrument; calculating a local slope of the surface using an overlapping transversal point, the pitch angle and the separation length; calculating a height variation using the local slope and a longitudinal separation.

Abstract: A method and a system for the detection of Foreign Object Debris (FOD) on a surface of a transport infrastructure are described. The method comprises receiving 3D profiles of the surface from at least one 3D laser sensor, the 3D laser sensor including a camera and a laser line projector, the 3D laser sensor being adapted to be displaced to scan the surface of the transport infrastructure and acquire 3D profiles of the surface; analyzing the 3D profiles using a parametric surface model to determine a surface model of the surface; identifying pixels of the 3D profiles located above the surface using the surface model; generating a set of potential FOD by applying a threshold on the pixels located above the surface model to identify a set of at least one protruding object; providing detection information about the potential FOD.

Abstract: Measuring a distance to a surface while compensating for variations in a transverse position and/or low speed displacement of the instrument. One method includes retrieving a predetermined transversal distance from a longitudinal feature at which to extract a relevant distance; retrieving a distance set; retrieving a position of the longitudinal feature relative to the distance set; extracting a range point at the predetermined transversal distance from the longitudinal feature; adding the extracted point to a longitudinal distance set. In another method, if two sensors are provided with an overlap in the transversal direction, extracting a range point at a predetermined transversal position; adding the extracted range point to a longitudinal distance set; retrieving a pitch angle of the instrument; calculating a local slope of the surface using an overlapping transversal point, the pitch angle and the separation length; calculating a height variation using the local slope and a longitudinal separation.

Abstract: A protected light source for generating seed light for at least two wavelength division multiplexed passive optical networks (WDM-PONs). The protected light source includes an optical coupler having N?2 input ports and M?2 output ports, each output port being optically connected to supply seed light to a respective set of one or more WDM-PONs. A respective multi-wavelength light source (MWLS) is optically coupled to supply seed light to each input port of the optical coupler. A controller unit controls operation of each multi-wavelength light source (MWLS).

Abstract: A protected light source for generating seed light for at least two wavelength division multiplexed passive optical networks (WDM-PONs). The protected light source includes an optical coupler having N?2 input ports and M?2 output ports, each output port being optically connected to supply seed light to a respective set of one or more WDM-PONs. A respective multi-wavelength light source (MWLS) is optically coupled to supply seed light to each input port of the optical coupler. A controller unit controls operation of each multi-wavelength light source (MWLS).

Abstract: A protected light source for generating seed light for at least two wavelength division multiplexed passive optical networks (WDM-PONs). The protected light source includes an optical coupler having N?2 input ports and M?2 output ports, each output port being optically connected to supply seed light to a respective set of one or more WDM-PONs. A respective multi-wavelength light source (MWLS) is optically coupled to supply seed light to each input port of the optical coupler. A controller unit controls operation of each multi-wavelength light source (MWLS).

Abstract: A system for overlaying an analog broadcast channel in a Wavelength Division Multiplexed Passive Optical Network (WDM-PON). A remote node of the WDM PON includes a MUX/DEMUX for demultiplexing a Wavelength Division Multiplexed (WDM) signal and supplying respective wavelength channels to each one of a plurality of channel fibers; an optical power splitter for supplying the analog broadcast channel to each one of a plurality of distribution paths; and a respective optocoupler connected to each distribution path, each opticoupler coupling the analog broadcast channel into one of the channel fibers. The analog broadcast channel has a wavelength that is outside a wavelength band of the WDM signal. An Optical Network Terminal (ONT), which is connected to one of the channel fibers, includes a triplexer for separating the analog broadcast channel from at least a downlink wavelength channel of the WDM-PON.

Abstract: A protected light source for generating seed light for at least two wavelength division multiplexed passive optical networks (WDM-PONs). The protected light source includes an optical coupler having N?2 input ports and M?2 output ports, each output port being optically connected to supply seed light to a respective set of one or more WDM-PONs. A respective multi-wavelength light source (MWLS) is optically coupled to supply seed light to each input port of the optical coupler. A controller unit controls operation of each multi-wavelength light source (MWLS).

Abstract: The invention relates to optical communications using techniques for providing efficient high speed polarization bit interleaving. One common architecture for high-speed time-division-multiplexing employs two modulators having a same bit rate, wherein two separately modulated streams of data bits are combined into a high-speed single serial stream of data bits, instead of providing a single higher-cost higher-speed modulator. The present invention has found with the availability of fast data modulators, that polarization bit interleaving can be employed more efficiently for higher speed data transmission in optical network systems by providing an optical modulator including a single data modulator, rather than multiplexing different data streams from different modulators.

Abstract: In a method of compensating polarization dependent loss (PDL) in a wave division multiplex (WDM) optical communications system, a performance parameter is monitored at a predetermined monitoring point. The performance parameter is indicative of respective channel PDL for each one of a plurality of channels of the optical communications system. A error function is calculated as a function of wavelength across a wavelength spectrum of interest, using the measured performance parameter values. Finally, a broadband PDL compensator is controlled based on the calculated error function.

Abstract: In a method of compensating polarization dependent loss (PDL) in a wave division multiplex (WDM) optical communications system, a performance parameter is monitored at a predetermined monitoring point. The performance parameter is indicative of respective channel PDL for each one of a plurality of channels of the optical communications system. A error function is calculated as a function of wavelength across a wavelength spectrum of interest, using the measured performance parameter values. Finally, a broadband PDL compensator is controlled based on the calculated error function.

Abstract: A control system is designed to control an optical cross-connect having a switch core defined by first and second independently movable beam deflectors capable of selectively defining an optical path between a pair of ports of the optical cross-connect. An optical element having optical power is arranged in a propagation path of light beams between the first and second beam deflectors. The control system includes a pilot light source, an optical sensor associated with each beam deflector, and a feedback path. The a pilot light source inserts a pilot light into the switch core colinearly with live traffic. The optical sensor detects a predetermined geometric property of the pilot light emerging from the switch core. This predetermined geometric property is unambiguously associated with an angular position of the associated beam deflector. The feedback path actively controls a position of the associated beam deflector based on the detected geometric property.

Abstract: A control system is designed to control an optical cross-connect having a switch core defined by first and second independently movable beam deflectors capable of selectively defining an optical path between a pair of ports of the optical cross-connect. An optical element having optical power is arranged in a propagation path of light beams between the first and second beam deflectors. The control system includes a pilot light source, an optical sensor associated with each beam deflector, and a feedback path. The a pilot light source inserts a pilot light into the switch core colinearly with live traffic. The optical sensor detects a predetermined geometric property of the pilot light emerging from the switch core. This predetermined geometric property is unambiguously associated with an angular position of the associated beam deflector. The feedback path actively controls a position of the associated beam deflector based on the detected geometric property.

Abstract: The invention relates to optical communications using techniques for providing efficient high speed polarization bit interleaving. One common architecture for high-speed time-division-multiplexing employs two modulators having a same bit rate, wherein two separately modulated streams of data bits are combined into a high-speed single serial stream of data bits, instead of providing a single higher-cost higher-speed modulator. The present invention has found with the availability of fast data modulators, that polarization bit interleaving can be employed more efficiently for higher speed data transmission in optical network systems by providing an optical modulator including a single data modulator, rather than multiplexing different data streams from different modulators.

Abstract: A method and apparatus for embedding control information in an optical signal transporting optical data, consisting of encoding the control information as a control signal having an amplitude proportional to a controllable modulation depth. The optical signal is then optically modulated in accordance with the amplitude of the control signal. The control signal is subsequently detected and the control information is decoded. A major feature of the invention lies in determining a level of similarity between the encoded and decoded control information and varying the modulation depth according to this level of similarity. Hence, the modulation depth yielding a given bit-error rate (BER) or signal-to-noise ration (SNR) can be minimized, in order to reduce the degradation of the optical channel data. The invention also provides a means for modulating the control information about a carrier frequency, and varying this carrier frequency if the SNR is below a certain tolerance value.

Abstract: The power of an optical signal (s1) travelling on a channel (&lgr;1) of a WDM transmission system, is measured using a signature bit pattern (sBP1) which is inserted in the frame of the optical signal (s1). The power level of sBPL is adjusted at the launching point to a predetermined ratio (m) with the power of the optical signal. At a point of interest, the fiber is tapped and a fraction of the tapped signal, that includes a corresponding fraction of sBP1, is converted to an electrical signal. The fraction of sBP1 is extracted from a the electrical signal and power of sBPL is measured. This gives the optical power of s1 as (m) is known and also the calibration constant for the respective channel (&lgr;1) is known. The method can be applied for any and all channels of the WDM transmission system.

Abstract: The variables and parameters previously understood to affect the gain spectrum of an optical amplifier 13 were: (1) the wavelengths to be amplified; (2) the input power levels at those wavelengths; (3) the characteristics of the amplifying medium 20; (4) the insertion loss spectra of the amplifier's components, including any filter(s) used for gain flattening; (5) the pump band chosen to pump the amplifying medium 20; and (6) the total amount of pump power supplied in the chosen pump band. An additional fundamental variable has been identified which can be used to control the gain spectrum of an optical amplifier 13, namely, the center wavelength of the spectrum of the pump's output power within the chosen pump band. Methods and apparatus for using this variable for this purpose are disclosed.For example a, transmission system is disclosed having a transmitter 11 and a receiver 10 connected by an optical fiber 12.

Abstract: An add/drop multiplexer/demultiplexer (ADM) for switching, modulating and attenuating optical signals in a fiber optic network employing wavelength division multiplexing (WDM) is disclosed. The ADM is equipped an optical multiplexer for splitting an input WDM signal into individual optical signals, leading to respective 2.times.2 switches. Each switch has another input originating from a plurality of "add lines", and selects one of its inputs to be dropped and the other to continue along a main signal path. The retained signals may be modulated and attenuated prior to being tapped and finally multiplexed together by a WDM multiplexer. The tapped signals are optoelectronically converted and fed back to a controller, preferably a digital signal processor running a software algorithm, which controls the switching, modulation and attenuation.