4 results about "Wdm transmission" patented technology

The invention provides an optical fiber channel waveform level modeling method and system based on a low-complexity Transform. The method comprises the following steps: building a coherent optical wavelength division multiplexing transmission simulation system; generating and collecting input and output signal data under different optical fiber cross-section conditions; preprocessing the original data set to realize dispersion separation; constructing data sets A and B for two-stage training; a low-complexity Transform model including sliding window attention, rotation position coding, a feedforward neural network and a residual connection module is established; training the model; and modeling the optical fiber channel by using the trained model. According to the method, the problems of high calculation complexity and limited modeling capability of the existing Transform in optical fiber channel modeling are solved.

The application discloses a filter based on a multi-mode subwavelength grating. The filter comprises a mode demultiplexer for multiplexing and demultiplexing of a base mode and a high-order mode, a subwavelength grating for weakly binding regulation of a mode field of the base mode and the high-order mode, and a straight-through waveguide for output of the base mode. The application introduces a structure of the subwavelength grating and weakly binding regulation of the mode field, and by virtue of excellent flat dispersion regulation characteristics, the application realizes apodization of the grating while keeping consistent local refractive index of the grating, thereby obtaining the filter with high side mode suppression ratio and no free spectral range limitation, and the filter can realize flat and low-loss spectral response, meets the next-generation large-capacity and high-speed wavelength division multiplexing transmission demand, and has the advantages of simple structure, simple process, excellent performance and the like.

In a parallel optical communication system technology, there has been a problem that group delay times are generally different between wavelength channels and between spatial channels and that reception times of an optical clock signal and an optical main signal are misaligned.　An optical communication system 301 according to the present invention performs wavelength multiplexing and transmission of an optical main signal Lsig and an optical sub-signal (clock signal) Lclk to an optical transmission line 50. The optical communication system is characterized in that the optical main signal Lsig and the optical sub-signal Lclk are respectively assigned to a wavelength in a normal dispersion wavelength region and a wavelength in an abnormal dispersion wavelength region of the optical transmission line 50.

The present invention relates to a method for dual-polarisation WDM transmission over optical fibre. The transmission method uses specific I / Q coding for combating the effects of PDL. The modulation symbols to be transmitted on the 2N polarisation states of the N wavelengths are broken down into real values and imaginary values (220). A first orthogonal linear transformation (230-1) is applied to the vector of the real values thus obtained and a second orthogonal linear transformation (230-2), separate from the first, is applied to the vector of the imaginary values thus obtained. A complex scalar solving an irreducible polynome of [X] in is multiplied with the first or second transformed vector before the two transformed vectors are summed (240) in order to provide a vector of transmission symbols for modulating the different states of polarisation of the WDM channels.