摘要:
A selective frequency extractor is disclosed which forwards one or more selected frequencies of a wavelength division multiplex input signal consisting of N channels to one output port and all the other frequencies to another output port. A reconfigurable frequency add and drop multiplexer is also disclosed. The input signal is divided up by a first demultiplexer and routed to a plurality of interleaved stages of optical switches for selectively feeding a plurality of input ports of a multiplexer, whose routing properties are then used for extracting one or more frequencies from the input signal or for reconfigurable frequency add and drop multiplexing.
摘要:
The invention relates to a reconfigurable optical switching system for selectively coupling one or more frequencies of first and second input wavelength division multiplex signals (WDM1, WDM2) consisting of N channels to first and second output ports (O1, O2). The invention also relates to a variable and reconfigurable optical delay circuit comprising said optical switching system associated with an optical delay loop. The input frequency division multiplex optical spectra (WDM1, WDM2) are therefore divided by a first demultiplexer (Demux) to a plurality of interleaved stages of optical switches (D, C, A and B) which selectively feed a plurality of input ports (Mi) of a multiplexer (Mux), which then uses its routing properties to implement in particular the complex reconfigurable multiple 2×2 frequency switching function.
摘要:
A device for reducing time distortion generated in light pulses by an optical frequency converter including at least one nonlinear optical component (4) having a nonlinear optical susceptibility χ of about 2 or 3, the converter being capable of receiving at least one incident pulse light beam (2), the incident light pulses having a duration Δt0, an optical frequency ω0±Δω0 and an intensity I0(t), and of generating, by frequency conversion, at least one output pulse beam (3), the output light pulses having a duration Δt1, an optical frequency Δ1±Δω1 different from ω0±Δω0, and an intensity I1(t). The time distortion-reducing device includes a pre-compensation linear time filter (5) provided on the path of the incident beam (2), and capable of reducing the intensity time distortions generated in the frequency-converted output light pulses to at least one pre-compensation intensity Icomp.
摘要:
The invention concerns a polarization-maintaining fiber-optic transmission system. The invention concerns a fiber-optic transmission system comprising at least one polarization maintaining fiber coupling an input device to an output device. The fiber comprises at least a first (F1) and a second (F2) polarization maintaining fiber section having each a slow propagation axis and a fast propagation axis. One end of the first fiber section is coupled to one end of the second fiber section such that the slow propagation axis of the first fiber section coincides with the fast propagation axis of the second fiber section and inversely. The invention is applicable in particular to lasers.
摘要:
A method and a device for compensating the polarization mode dispersion (PMD) of a transmitted optical signal comprise means of a polarization controller (3) coupled to a differential group delay (DGD) generator (5). The polarization controller (3) is controlled by a feedback loop, said feedback loop implementing an optimisation algorithm to optimize a feedback parameter of the output signal of the DGD generator (5). The algorithm takes into account the state of polarization (SOP) of an optical signal determined from the output signal of the polarization controller (3)) or from the output signal from the DGD generator (5).
摘要:
A method for spreading a spectrum of a narrowband signal, e.g. a monochromatic optical signal or a radiofrequency carrier. The method uses a phase modulation using a modulation signal that includes a plurality of sinusoidal components, the plurality including a component at a fundamental frequency and at least one component at a frequency that is a harmonic of the fundamental frequency, the sinusoidal components being synchronous and affected with phases respectively equal to consecutive multiples of π/2.
摘要:
The present invention relates to an optical communication network and to a network element for use in such a network. The network element comprises a plurality of receivers (70-76) for receiving optical communication signals, a plurality of transmitters (54-62, 82-86) for transmitting optical communication signals, and a plurality of network connections, each network connection having an individual signal impairment characteristic. The pluralities of receivers (70-76) and transmitters (54-62, 82-86) are adapted to employ a plurality of different modulation schemes (64, 66). Furthermore, the pluralities of receivers (70-76) and transmitters (54-62, 82-86) are assigned to the network connections as a function of the individual signal impairment characteristics.
摘要:
A decision system for a modulated electrical signal delivered by a converter in response to a received modulated optical signal compares the amplitude of the electrical signal to a reference level, measures an average amplitude of the electrical signal, and generates the reference level as a function of the result of such measurements so that the “reference level/average amplitude” ratio can be adjusted to a predetermined constant value different from 1. Applications include receivers for optical packet transmission systems.
摘要:
The optical switching device (100) includes: an optical switching matrix (1) including: input ports (A, B), output ports (a, b), switching means (3, 3′) between the input ports (A, B) and the output ports (a, b), and control means (2) for the switching matrix (1), and optical paths are defined between the input ports (A, B) and the output ports (a, b) so that data entering via one of the input ports (A, B) is switched by the matrix (1) to exit at one of the output ports (a, b). The device is characterized in that the control means (2) include at least one configuration table (14) in which are written authorized optical paths producing a transmission error rate lower than a predetermined value.
摘要:
In order to increase the distance over which binary data can be transmitted over an optical fiber, the device compensates for fiber-generated chromatic dispersion by modulating the emitted light wave both in power and in phase, in such a manner as to ensure that there is a phase shift of close to 180.degree. within each binary cell for which the optical power is low but not zero. The device comprises a Mach-Zehnder type interferometer made on a substrate of III-V elements and designed so that in the absence of electrical voltages being applied to its electrodes it establishes destructive interference. A control circuit applies control voltages to the electrodes which voltages have DC components that are substantially equal, with at least one of the control voltages being the result of superposing a bias voltage on a filtered signal obtained by lowpass filtering an input electrical signal. The invention is applicable to long distance transmission over standard optical fibers.