181results about "Optical mode multiplex systems" patented technology

An optical communication system comprises a transmitter optically coupled to a single-mode optical channel, and a multimode optical fibre configured to support transmission of a plurality of guided modes. The plurality of guided modes comprises a target mode. The system further comprises an optical mode converter configured to optically couple the mode of the channel to the target mode of the multimode fibre by gradually changing a transverse profile of propagating light received from the channel to match a transverse profile of the target mode of the multimode fibre.

The invention discloses a method of an optical anti-turbulence device for polarization multiplexing spatial optical communication. The mode demultiplexer is connected with the optical fiber; the single-mode optical fiber array is respectively coupled with each spatial intrinsic mode decomposed by the mode demultiplexer; the polarization CBC chip is connected with the other end of the single-mode optical fiber array; the driving control module is connected with the polarization CBC chip; the polarization multiplexing optical communication digital coherent receiver (Rx) is connected with the polarization CBC chip through a single-mode optical fiber; through the arrangement of the polarization CBC chip, the compatibility of a polarization multiplexing technology and a mode multiplexing coherent beam combination technology is realized, the problem of polarization dimension information loss or strong crosstalk caused by the use of a polarization state rotator (PSR) and a polarization maintaining optical fiber in the prior art is solved, modulation information of two orthogonal polarization dimensions is completely reserved, the communication bandwidth is improved, and the communication efficiency is improved. And the communication efficiency is greatly improved.

The invention relates to the technical field of multi-plane light conversion, in particular to a multi-dimensional demultiplexing and frequency mixing system based on an MPLC and an optimization design method of the multi-dimensional demultiplexing and frequency mixing system. The system comprises an input module used for inputting multimode signal light and local oscillation light; the MPLC module is used for realizing unitary transformation of light in any space, comprises N cascaded phase transformation areas and is integrated on the reflecting mirror or the transmitting mirror; the phase transformation regions are phase plates or metasurfaces, and at least one phase transformation region is a metasurface; and the output module is used for receiving the single-mode Gaussian light spots after demultiplexing and frequency mixing. According to the invention, different phases of different wavelengths and different polarization states are regulated and controlled through the metasurface; parallel demultiplexing of wavelengths, polarization and modes in multimode signals can be realized.

The invention discloses a wavelength division and mode division multiplexing multiply-adder which loads first data to be calculated on a first group of optical signals, and the first group of optical signals comprises a plurality of optical signals with different powers. The wavelength mode multiplexing module then converts the first set of optical signals into a first optical signal. The first optical signal is divided into a plurality of second optical signals through a power beam splitting module. Converting the plurality of second optical signals into a plurality of groups of second group optical signals through a mode demultiplexing module; then, the modulation module loaded with the partial data of the second data outputs a third group of optical signals after adjusting the light intensity of the second group of optical signals. And finally, combining the plurality of third groups of optical signals into a plurality of third optical signals through a beam combining module, wherein the product of the first group of data and the second group of data is indicated. According to the invention, the calculation power consumption can be saved, in addition, the optical signals are distinguished by using modes and wavelengths, the increase of calculation dimensions is facilitated, and large-scale matrix vector multiplication is realized.

The invention discloses a relay device and method for long-distance few-mode optical fiber communication, and belongs to the field of optical communication. According to the device, firstly, optical signals transmitted in a few-mode optical fiber are separated into a plurality of independent mode channels through a mode decomposition multiplexer; then, an adjustable light delay unit is configured in each channel, and compensation is carried out according to a difference mode group delay difference pre-calculated or actually measured by a few-mode optical fiber parameter; furthermore, a dimmable amplifier is used for amplifying the signal, power monitoring is carried out at the output end of the amplifier through an optical fiber beam splitter and a photoelectric detector, closed-loop feedback control is formed, and gain of each channel is adjusted in a self-adaptive mode to eliminate mode-dependent loss. According to the invention, signal distortion can be effectively suppressed in an optical domain, the complexity of digital signal processing of a receiving end is reduced, and the transmission distance and the transmission capacity of a few-mode optical fiber mode division multiplexing communication system are remarkably improved.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitter of orbital angular momentum (OAM) multiplexing based communication may transmit, to a receiver of the OAM multiplexing based communication, a configuration message that indicates a configured set of transmitter circles. The transmitter may transmit, to the receiver, at least one data stream using the configured set of transmitter circles. Numerous other aspects are provided.

An optical communication system can include a multiplexer / demultiplexer. The multiplexer / demultiplexer can transfer a first optical data signal between a first single-mode fiber and a first propagation mode of a few-mode fiber. The first propagation mode can have a first effective refractive index. The multiplexer / demultiplexer can transfer a second optical data signal between a second single-mode fiber and a combination of a second propagation mode of the few-mode fiber and a third propagation mode of the few-mode fiber. The second propagation mode and the third propagation mode can have a same effective refractive index that differs from the first effective refractive index. During propagation within the few-mode fiber, the second optical data signal can couple bidirectionally between the second propagation mode and the third propagation mode, while being substantially isolated from the first optical data signal in the first propagation mode.

Methods, systems, and devices for connection setup in an orbital angular momentum (OAM)-based communication system are described. A first device and a second device may establish an OAM communications connection between the devices. The first device and the second device may exchange a series of messages over a downlink communications link and an uplink communications link according to an OAM mode. Based on OAM related parameters or OAM related information included in the messages, the first device and the second device may achieve a successful directional alignment (co-axial alignment) between the first device and the second device. The first device and the second device may determine one or more orbital angular momentum modes for communication between the first device and the second device based on the establishing the directional alignment.

A method and apparatus are provided. The method includes receiving, at a TE0 mode add / drop filter, a TE0 mode optical signal having a first wavelength and a second wavelength, and transmitting, from the TE0 mode add / drop filter, the TE0 mode optical signal having the first wavelength and the second wavelength towards a Bragg grating, without converting the TE0 mode optical signal having the first wavelength and the second wavelength to another mode. The method further includes receiving, at the TE0 mode add / drop filter, a reflected TE1 mode optical signal having the first wavelength from the Bragg grating, and transmitting, from the TE0 mode add / drop filter, the reflected TE1 mode optical signal having the first wavelength towards a photodetector, without converting the reflected TE1 mode optical signal having the first wavelength to another mode.

The invention discloses a multi-mode optical switch and a multi-mode optical transmission system, and relates to the technical field of optical switchs.The multi-mode optical switch comprises a first beam splitter, an optical signal modulation assembly and a second beam splitter, and the first beam splitter is provided with an input port, a first output port and a second output port; the signal input end of the optical signal modulation assembly is connected to the first output port. The second beam splitter is provided with a third input port, a fourth input port, a third output port and a fourth output port, the third input port is connected to the second output port, and the fourth input port is connected to the signal output end of the optical signal modulation assembly; according to the technical scheme provided by the invention, the integrity of the multi-mode signal can be maintained, and meanwhile, the sub-millisecond-level high-speed switching is realized.

The invention relates to an underwater point cloud data transmission system and method based on vortex light mode division multiplexing, and the system comprises a point cloud data transmission module which is used for modulating the three-dimensional point cloud data of a measured target into two paths of laser signals, carrying out the first preprocessing of the two paths of laser signals, and transmitting an underwater space light signal; and the point cloud data receiving module is used for receiving the underwater space optical signal, performing second preprocessing on the underwater space optical signal, and generating user service data. According to the invention, a double-path vortex optical space division multiplexing technology is adopted, synchronization of target detection and data return is realized, and key technical problems of poor real-time performance, weak anti-interference capability and the like in the aspect of underwater three-dimensional point cloud data acquisition are effectively solved.

Intensity control units 40A and 40B acquire the intensity of backscattered light when inputting signal light of two or more modes for each core in a multicore optical fiber 10, which has two or more cores and in which two or more modes propagate to each of the cores, so that the transmission direction of light differs between adjacent cores, and output a control signal for reducing the input optical power of a high-order mode other than a basic mode of the signal light by a predetermined amount so as to reduce the influence of the high-order mode on the basic mode.

The invention discloses a mode division multiplexing optical fiber communication phase calibration method based on CNN-LSTM, and belongs to the technical field of optical fiber communication. By constructing a double-input CNN-LSTM hybrid neural network architecture, MIMO input signals and original target signals of mode division multiplexing optical fiber communication are obtained, data preprocessing is carried out, and the spatial feature extraction capability of a convolutional neural network and the time sequence modeling capability of a long-short-term memory network are combined, so that the MIMO input signals and the original target signals of mode division multiplexing optical fiber communication are obtained. Effective compensation of phase noise in long-distance strong-coupling mode division multiplexing optical fiber communication is realized, and a double-branch network comprising an image input layer, a convolutional layer, an LSTM layer, a deep connection layer and a user-defined phase calibration layer is constructed by separating complex MIMO signals into real and imaginary parts and generating a sliding window training sample. The problems that a traditional algorithm is limited in phase noise compensation capacity and poor in convergence performance under the strong coupling condition are effectively solved, and the balance performance and the transmission quality of a mode division multiplexing optical fiber communication system are remarkably improved.

The invention discloses a free space optical communication system based on a structured optical frequency comb, and belongs to the field of optical communication. Comprising an optical frequency comb generation system, a signal coding system, a spatial light modulation and demodulation system and a signal receiving system. The optical frequency comb generation system is used for modulating input continuous laser into an adjustable optical frequency comb with high repetition frequency, short pulse width and high power; the signal coding system is used for separating the light with different wavelengths in the optical frequency comb, independently coding the light with each wavelength, and finally combining the light with different wavelengths again; the spatial light modulation and demodulation system is used for coupling the Gaussian beam in the optical fiber into a free space and converting the Gaussian beam into structured light, demodulating the structured light after the structured light is transmitted to a receiving end and re-coupling the structured light back to the optical fiber; the signal receiving system is used for receiving and analyzing the optical signals. According to the invention, the optical frequency comb and the structured light are combined, and the problem that optical signals are easily influenced by atmospheric turbulence in free space optical communication can be effectively solved on the premise of ensuring large communication capacity.

To make it possible to design a multi-core optical fiber having a standard cladding diameter taken in consideration of manufacturability.SOLUTION: The present disclosure provides a multi-core optical fiber comprising: two or more cores through which two or more lightwave modes propagate; a cladding a refractive index of which is lower than that of the cores and which is disposed so as to include all the cores; and an outermost layer a refractive index of which is equal to or more than that of the cladding and less than that of the cores and which is disposed on a concentric axis so as to surround the cladding. A crosstalk between the cores in the highest order propagation mode propagating through the cores is -39 dB / km or less.SELECTED DRAWING: Figure 1

A multimode combiner is disclosed. In one aspect, a multimode combiner includes a first input waveguide, a second input waveguide, and an output waveguide disposed between the first and second input waveguides. The first input waveguide, the second input waveguide, and the output waveguide are arranged such that an optical signal transmitted through the multimode combiner has substantially the same optical power at an output of the output waveguide as the optical signal does at an input of either of the first and second input waveguides. A multiplexer and an apparatus including multimode combiners are also disclosed.

Aspects relate to photonic computing systems and methods of optically performing matrix vector multiplication. A photonic computing system includes a light source configured to generate a plurality of input optical signals having mutually different wavelengths, a plurality of optical encoders configured to encode the plurality of input optical signals with respective input values, a first wavelength division multiplexer (WDM) configured to spatially combine the encoded plurality of input optical signals into an input waveguide, a photonic multiplier coupled to the input waveguide and configured to generate a plurality of output optical signals each encoded with a respective output value representing a product of the respective input value and a common weight value, and a second WDM coupled to the photonic multiplier and configured to spatially separate the plurality of output optical signals.

Aspects of this technical solution are directed to multiplexed transmission by optical beam transmission. A method can include generating a first beam having a first frequency in an optical frequency range, generating a second beam including data and having a second frequency in the optical frequency range, converting the first beam and the second beam into a third beam including the data and having a third frequency based on a difference between the first frequency and the second frequency, and transforming the third beam into a fourth beam having a first angular distribution and including a first portion of the data, and into a fifth beam having a second angular distribution corresponding to the first angular distribution and including a second portion of the data.

The application relates to a unique optoelectronic module configured to operate simultaneously at high-speed bit rate and low speed bit rate, thanks to a reconfigurable system on a chip, i.e. a programmable unit on a chip. This reconfigurable system embeds the electronic circuitry of the low-speed channel(s), i.e. at least the driver when the link is a transmission channel, or at least the amplifier when the link is a receiver channel.

One aspect of the present invention is an optical transmission system including a transmitter connected to a transmission line having M spatial channels, and a receiver that receives a signal transmitted from the transmitter via the transmission line, wherein the transmitter includes: an allocator that allocates a transmission bit string transmitted to the transmission line into a bit string serving as a basic signal and a bit string serving as spatial channel information; a generator that generates N (M>N) signals from the bit string serving as the basic signal allocated by the allocator; and a selector that selects N spatial channels, through which the N signals generated by the generator are transmitted, from the M spatial channels on the basis of the bit string serving as the spatial channel information allocated by the allocator.

The application discloses a spatial-mode hybrid diversity receiving system for spatial laser communication. After a transmitting light beam passes through atmospheric turbulence, diffusion and distortion and other phenomena occur, spatial diversity and mode diversity are combined at a receiving end, an array of M receiving antennas is used to receive the diffused light beam to perform spatial diversity, a few-mode fiber supporting N modes is connected after each receiving antenna, high-order modes are converted into base modes by a mode demultiplexer and then output to a single-mode fiber to perform mode diversity, then a total of M*N branch signals are converted into electric signals by photoelectric detection modules, and finally, the branch signals are combined after digital signal processing. The application combines spatial diversity and mode diversity, can effectively compensate the influence of atmospheric turbulence on laser transmission, and is beneficial to spatial laser communication under more severe channel conditions.

Systems and methods are described for transmitting information optically in free space. For instance, a system may include an optical signal generator to generate an amplified beam of light. A telescope transmits the amplified beam through the medium and receives an inbound beam of light. A detector system may include one or more (or multiple) detectors and a routing system that transmits the inbound beam to a selected set of detectors. In some cases, the system can determine a re-configuration condition based on control parameters and perform a system re-configuration to direct the inbound beam to a different set of detectors. In some cases, the system includes a remote fiber head or wavelength division multiplexing.

Systems and methods include an optical transceiver configured to be connected to an optical cable (102) having multiple optical fiber cores, the optical transceiver including multiple transmitters (108) and multiple receivers (106), wherein the transmitters are connected to a first group of optical fiber cores in the optical cable and the receivers are connected to a second group of optical fiber cores in the optical cable. The optical transceiver includes an array of elements, wherein each element includes a pLED and a photodetector connected to a programmable conductor so that a training algorithm selects which conductors become active conductors in a data path. Associated circuitry such as a driver for the pLED and a TIA for the PD is also part of each element.

A spatiotemporal optical multiplexer includes a storage optical cavity having a plurality of storage-cavity modes that are transversely separated, a dump optical cavity having a plurality of dump-cavity modes that are transversely separated, and a phase modulator located in the dump cavity and overlapping all of the dump-cavity modes. Each dump-cavity mode is coupled to a respective storage-cavity mode. The storage-cavity modes have the same storage-cavity resonant frequency while the dump-cavity modes have dump-cavity resonant frequencies that are distinct. The phase modulator is driven to simultaneously tune the dump-cavity resonant frequencies. At any time, no more than one dump-cavity mode is resonant with its respective storage-cavity mode. When this resonance occurs, the energy of the respective storage-cavity mode is coupled out of the storage cavity and through the dump cavity as an output pulse.

The invention discloses a multi-channel low-crosstalk multi-layer stepped annular optical fiber and a design method thereof, and belongs to the field of optical communication, and the multi-layer stepped annular optical fiber comprises n (n is greater than or equal to 5 and less than or equal to 10) nested annular structure layers which are sequentially the first to nth annular structure layers from inside to outside; the refractive index of the outermost annular structure layer is smaller than or equal to that of silicon dioxide; the refractive indexes of the first to (n-3) th annular structure layers are greater than the refractive index of the outermost annular structure layer; the refractive index of the (n-2) th embedded structure layer is equal to that of the outermost annular structure layer; the refractive index of the (n-1) th annular structure layer is smaller than that of the outermost annular structure layer; the refractive indexes of the adjacent annular structure layers are different; the width range of the first annular structure layer to the (n-1) th annular structure layer is 1-6 [mu] m and is smaller than the width of the outermost annular structure layer. The number of orbital angular momentum modes which can be supported by the optical fiber and are good in effective refractive index separation can be increased, and therefore the optical communication capacity is improved.

The invention discloses an active mode demultiplexing module which comprises a mode converter, two optical circulators and a bidirectional semiconductor optical amplifier. The mode converter is used for converting a high-order mode into a fundamental mode to complete primary mode demultiplexing, fundamental mode signals after primary demultiplexing are injected into the bidirectional semiconductor optical amplifier through the two optical circulators from the positive direction and the negative direction respectively, and the signals after being shaped by the bidirectional semiconductor optical amplifier are output by the corresponding optical circulators. A bidirectional symmetrical injection structure is formed, different propagation is beneficial to separation of different signals, and mutual interference, namely mode crosstalk, between forward and reverse signals can be effectively reduced, so that a mode demultiplexing function is better completed, and an output signal has higher signal quality than a primary demultiplexing signal. Besides, by optimizing and adjusting the driving current of the bidirectional semiconductor optical amplifier or an auxiliary optical pumping mode, not only can the gain of the mode channel be dynamically adjusted, but also the power balance of the mode channel and the demultiplexing of a high extinction ratio mode can be realized; the method is especially suitable for receiving few-mode signals in a mode division multiplexing (MDM) optical transmission system and constructing optical switching nodes in a multi-dimensional multiplexing optical network.

The invention discloses a signal-to-noise ratio and mode coupling joint estimation method and device for mode division multiplexing optical fiber communication and a storage medium, and the method comprises the steps: obtaining a plurality of groups of communication signals of the mode division multiplexing optical fiber communication, and obtaining a spectrum correlation function of the communication signals, determining a cyclic correlation function according to the spectrum correlation function, determining a signal-to-noise ratio and an optical fiber length according to the cyclic correlation function, and determining a power coupling coefficient value according to the signal-to-noise ratio and the optical fiber length corresponding to each group of communication signals. According to the method, the signal-to-noise ratio and mode coupling can be monitored at the same time, the communication quality can be evaluated more comprehensively through the combined monitoring capacity, and a complex data acquisition or synthesis process is not needed, so that implementation and operation of a monitoring system are simplified, real-time monitoring can be achieved, and reliability and timely detection of the communication system can be guaranteed. The method is widely applied to the technical field of optical communication.

To provide an optical amplifier that can perform Raman amplification while reducing power consumption and size.SOLUTION: A fiber Raman amplifier 10 includes a light source 130 and a multi-core fiber 110. The light source 130 outputs pumping light PL used to amplify a multiplexed optical signal SIG. The multi-core fiber 110 constitutes a distributed amplifier for the multiplexed optical signal SIG by cladding pumping using pumping light PL. The light source 130 outputs multiplexed multimode laser light.SELECTED DRAWING: Figure 3

An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

An optical fiber comprises a core having an elliptical cross section and a cladding having a circular cross section. The core has an ellipticity between 2 and 40. The core and the cladding have a common central axis with the core being enclosed by the cladding. The difference of a refractive index of the cladding to a refractive index of the core is between 1 x 10-2 and 1.5 x 10-1. A trench is located between the core and the cladding. The trench has a uniform width and encircles the core. The refractive index of the trench is lower than the refractive index of the cladding.