53results about "Optical mode multiplex systems" patented technology

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.

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.

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.

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 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.

An optical power adjustment system includes a multi-mode light source, a mode demultiplexer, and an optical power adjustment apparatus. The multi-mode light source is configured to output a multi-mode optical signal, where the multi-mode optical signal includes N transverse-mode optical signals, N=2M, and M is an integer greater than 1. The mode demultiplexer is configured to convert the N transverse-mode optical signals into N fundamental-mode optical signals, and output the N fundamental-mode optical signals. The optical power adjustment apparatus includes M optical power adjustment modules and a control apparatus, each optical power adjustment module includes a plurality of phase shifters, and the control apparatus is electrically connected to the M optical power adjustment modules. A Kth optical power adjustment module includes 2K-1 multi-mode interferometers MMIs.

The application relates to the technical field of multi-plane light converters, and more particularly to an on-chip multi-plane light conversion device and an optimization design method thereof. A grating coupling unit, a multi-plane phase sheet and a mirror are integrated on the same glass substrate, three-dimensional monolithic integration of input coupling, light path folding and light field transformation functions is realized, precise mechanical alignment requirements among discrete components are completely eliminated, the integration degree is high, high-precision alignment is avoided, stability is improved, and the volume is reduced to a certain extent. The application realizes efficient conversion of a light field between an on-chip waveguide and free space through the grating coupling unit, and performs arbitrary unitary transformation in the free space by using an MPLC composed of the multi-plane phase sheet and the mirror, the two work cooperatively, the high mode capacity and low crosstalk advantages of the MPLC are combined with the on-chip integration advantages of the grating coupling unit, and high-performance and small-volume light field transformation can be realized.

A high-resolution image transmission system based on optical communication specifically relates to the technical field of image transmission, and comprises a mode multiplexing transmission module configured to modulate a high-resolution image signal into a plurality of orthogonal transmission actual modes, an interference parameter acquisition module configured to acquire actual interference parameters of the actual modes, and a mode multiplexing transmission module configured to transmit the actual interference parameters to the mode multiplexing transmission module. The actual multiplexing efficiency calculation module is configured to calculate actual mode multiplexing efficiency by taking actual interference parameters as a deducting part of interference loss, and the detail transmission capability evaluation module is configured to calculate actual spatial frequency response bandwidth in combination with detail transmission capability influence, and evaluate the actual mode multiplexing efficiency according to the actual spatial frequency response bandwidth. And the dynamic phase adjustment module is configured to calculate a phase modulation gradient adjustment amount and drive the phase modulator to correct a phase deviation of an actual mode in real time until an image transmission balance condition is met. The purpose of stable, undistorted and detail-complete transmission of the high-resolution image is achieved.

This invention enables reduction of power consumption while ensuring the waveform quality of a received signal.　Provided is an optical communication system wherein a transmitter and a receiver are connected by an optical waveguide and communicate with each other using light of a second wavelength. Herein, the optical waveguide only propagates a fundamental mode at a first wavelength, and the second wavelength is a wavelength at which the optical waveguide can propagate at least a primary mode together with the fundamental mode. An inter-mode propagation delay difference adjusting unit makes an adjustment such that the primary mode lags by one unit interval relative to the fundamental mode in an optical communication path for the light of the second wavelength including the optical waveguide. Furthermore, for example, a mode ratio adjusting unit adjusts the ratio between the fundamental mode and the primary mode in the light of the second wavelength incident on the optical waveguide from the transmitter.

An optical communication system 1 comprising: a single-mode optical channel 21 having an optically coupled transmitter 9; a multimode optical fibre 5 configured to support transmission of a plurality

One aspect of the present invention is a signal detection device including a mode demultiplexer configured to convert N (N is a natural number) spatial mode signals including a plurality of higher modes excited in a transmission path fiber into N base modes and output the N basis modes, a frequency conversion unit configured to convert N optical signals into frequencies different from each other, a multiplexing unit configured to multiplex the N optical signals having frequencies that have been converted, and a reception unit configured to photoelectrically convert a multiplexed optical signal while maintaining modulation information for a phase and polarization, perform digital signal conversion and signal processing, and demodulate an original information sequence.

The application provides a self-adaptive UCA array arrangement method for generating a multi-mode vortex electromagnetic wave, which comprises the following steps: determining the number of concentric rings; determining the radius of a first concentric ring with the smallest radius; arranging every two adjacent concentric rings at equal intervals, and the interval is equal to the radius of the first concentric ring; dividing all the concentric rings into N equal parts according to the number N of array elements of the first concentric ring, and taking the N division points of the first concentric ring as the positions of the array elements of the first concentric ring; for each N division part of all the concentric rings, respectively placing array elements according to the positions of the array elements of the first concentric ring; taking all the concentric rings except the first concentric ring as the kth concentric ring, and dividing the N division part of the kth concentric ring into k equal parts, and taking the boundary points of the N division part and the k division points as the positions of the array elements of the kth concentric ring to place the array elements. The method can generate a high-quality OAM beam and has strong universality.

The invention discloses an adiabatic low-loss vortex structure optical multiplexing and demultiplexing device and an optical communication system, and belongs to the field of optical communication, and the optical multiplexing and demultiplexing device comprises a plurality of optical fiber vortex mode selection couplers with different orders, which are respectively used for exciting vortex mode groups with different orders; the optical fiber vortex mode selection coupler is formed by parallel fused biconical taper of a multimode optical fiber with a transition cladding and a single-mode optical fiber subjected to pre-tapering, the multimode optical fiber and the single-mode optical fiber form a directional coupling structure, and a fundamental mode in the single-mode optical fiber is matched with a vortex mode group in the multimode optical fiber in phase; the multimode optical fiber with the transition claddings comprises a fiber core and a plurality of transition claddings, the width of each layer is gradually increased from the fiber core to the outermost transition cladding, and the refractive index difference between every two adjacent layers is gradually decreased; and a plurality of optical fiber vortex mode selection couplers with different orders are cascaded to form a multi-stage multiplexing and demultiplexing structure. The heat insulation loss of the optical fiber mode selection coupler can be reduced, so that the optical fiber mode selection coupler supports more vortex mode numbers.

An optical input / output chip and distributed computing system, including: output sub-chip includes first light processing module to form N first light branches output from laser source, divide and modulate each first light branch into M first light sub-branches according to M wavelengths, form second optical branches containing N different modes from N modulated first optical branches before being output in first polarization state; input sub-chip includes second optical processing module, to form N third optical branches containing same mode from N second optical branches containing different modes, divide out part of light in each third optical branch having been converted from first polarization state to second, and form first polarization state again, combine and demodulate light in the first polarization state without conversion in original third optical branch after having been divided into M second optical sub-branches according to M wavelengths respectively. Thus increasing both communication rate and bandwidth effectively.

To provide a method for obtaining an optical processing condition, which can be corresponded to a high-speed signal, and can be corresponded to a transmission channel of which a mode scattering amount is large for compensating a mode scattering in a small calculation time and a small power consumption for a mode dispersion compensation.SOLUTION: A method for acquiring information for a mode dispersion compensation in order to obtain an optical processing condition for compensating a mode scattering in a mode division multiplex transmission using a multimode fiber, contains: an optical transmission step of transmitting an optical probe signal from a mode multiplexer in each mode of the first mode to Mth mode of the mode division multiplex transmission, and transmitting the multimode fiber; a frequency response measurement step of measuring a frequency response of a complex amplitude of the optical probe signal that has transferred the multimode fiber; and an information acquisition step for the mode dispersion compensation for acquiring the information for the mode dispersion compensation containing a group delay difference and a loss difference between the modes in the mode division multiplex transmission by using the frequency response of the complex amplitude of the first mode to the Mth mode.SELECTED DRAWING: Figure 2

A power splitter may include a single-core optical fiber, a beam-splitting optical fiber, and a multicore optical fiber. The beam-splitting optical fiber may include a polygonal core configured to output a multimode interference beam pattern including a plurality of beam spots, an input end coupled to the single-core optical fiber, and an output end coupled to the multicore optical fiber. In embodiments, a difference between a mode field diameter of the cores of the multicore optical fiber and a mode field diameter of the core of the single-core optical fiber may be less than or equal to 50%. In embodiments, when the power splitter is in operation, a difference between a distance between neighboring beam spots of the multimode interference beam pattern output by the beam-splitting optical fiber and a core pitch of the cores of the multicore optical fiber may be less than or equal to 10%.

The invention discloses a photon lantern mode crosstalk characterization device and method in a mode division multiplexing system, and belongs to the field of optical communication. The method can be used for performance evaluation and optimization of the multimode photon lantern in a mode division multiplexing system. According to the method, a wavelength mapping measurement method is used, and modes are in one-to-one correspondence with wavelengths, namely multiplexing and demultiplexing of the modes are converted into multiplexing and demultiplexing of the wavelengths; the specific method comprises the steps that light with different wavelengths emitted by the three lasers is input through the single-mode input end of the first photon lantern and output through the few-mode end of the first photon lantern, then the light is input through the few-mode end of the second photon lantern, and the received light is decomposed at the single-mode port of the second photon lantern through the wavelength division multiplexer according to different wavelengths; optical power meters are respectively used for optical power measurement, and crosstalk conditions of different modes of the photon lantern under the combined action of multiple channels can be obtained through calculation.

The invention provides a column vector light beam dynamic multiplexing and demultiplexing system based on ferroelectric liquid crystal and a use method thereof. The system comprises a transmitting end, a transmission section, a receiving end and an electric control driving control unit, the transmitting end generates and switches a column vector light beam topology through multi-path light source modulation, polarization setting and a ferroelectric liquid crystal Q wave plate, and the column vector light beam topology is coaxially superposed into a multiplexing light beam through a beam combiner; the transmission section bears light beam propagation; and a receiving end realizes selective demultiplexing through cascade inverse transformation of the ferroelectric liquid crystal Q wave plate and the liquid crystal variable delayer, and completes signal detection after polarization separation and single-mode coupling. And the electric control unit synchronously controls the state switching and channel addressing of each module. The system switching speed is remarkably increased, the stability is better, the system can work under the low driving voltage, the available channel set and the mapping relation can be adjusted according to needs, the resource scheduling requirement of burst traffic of a data center is better met, the system can be directly connected to a commercial receiver, and large-scale deployment is facilitated.

The invention discloses a broadband parallel information processing device and a broadband parallel information processing method for high-dimensional photon multiplexing driving, which are characterized in that three key parallel processing processes of frequency comb generation, time domain discretization and speed reduction decomposition are degenerated by utilizing joint multiplexing of M different wavelengths and N different modes; uniform multiplexing and in-phase driving in the same optical path are realized, receiving and processing of M * N paths of different analog signals are cooperatively completed, and orthogonality of each dimension is kept for subsequent reversible decoupling while amplitude-phase consistency and high synchronization among channels are ensured; an optical domain parallel processing architecture is utilized, time domain parallel decomposition is directly carried out on broadband signals in an analog optical domain, a single-path high-speed data stream is decomposed into 2K paths of parallel low-speed sub-channels, and the data volume and rate of each path are reduced to 1 / 2K of the original data volume and rate. According to the invention, a high-speed data transmission interface and a large-capacity storage unit required by traditional parallel computing are avoided, and the method is an effective scheme for realizing high-performance array broadband multi-dimensional signal receiving and processing in the future.

This makes it possible to mitigate performance degradation caused by mode-dependent losses without significantly increasing computational complexity. [Solution] The signal processing circuit includes a MIMO demodulation unit that includes a first MIMO filter and performs MIMO demodulation processing on multiple signals; a signal extraction unit that extracts a signal of a predetermined time slot from the output signal of the MIMO demodulation unit; a removal component generation unit that includes a second MIMO filter and generates a signal component to be removed, including interference components that occur between multiple modes, based on the signal output from the MIMO demodulation unit; an interference removal unit that generates a signal from which the signal component to be removed has been removed from the signal extracted by the signal extraction unit; and a coefficient control unit that uses the magnitude of the difference between the signal from which the signal component to be removed has been removed and a reference signal as a loss function, and adaptively controls the coefficients of the first MIMO filter and the second MIMO filter, respectively, using backpropagation and gradient descent.

The application discloses a kind of space division optical switching method and system based on optical mode label, the method with optical mode structure distribution characteristics as label (bridge), through optical wavefront phase multi-plane transformation, realize the arbitrary interconnection between multiple input ports / modes and multiple output ports / modes, the optical mode is various space mode, for example, Hermite-Gaussian, Laguerre-Gaussian, vortex, linear polarization, vector and so on mode;The multi-plane transformation can be loaded on spatial light modulator, for the light of each input port / mode is modulated according to the wavefront phase of space / mode phase distribution Multi-level (multiple) transformation, so that the light of each space port / mode is transformed to the space port / mode needed.The system structure is simple, can match various input / output interface, supports wide spectrum communication, compatible with wavelength division multiplexing system, can be used to constitute super large multi-dimensional optical switching system.

Aspects of the disclosure provide a device and method of adjusting received signals to correct for errors resulting from mode mixing in a multimode fiber (20,410,510) using an optical phased array (OPA) photonic integrated circuit (PIC) (112, 132, 500a, 500b) based device. The method including receiving, at an OPA PIC (112, 132, 500a, 500b), a first signal from the multimode fiber (20,410.510); receiving, at the OPA PIC (112, 132, 500a, 500b), a plurality of control wavelengths, wherein each of the plurality of control wavelengths is encoded with a distinct spatial mode and wherein the first signal and the plurality of control wavelengths are co-propagating signals; determining, by one or more processors (512,512b) of the OPA PIC (112, 132, 500a, 500b), a cross-coupling matrix based on the control wavelengths, the cross-coupling matrix being indicative of errors in the first signal; and adjusting, by the one or more processors (512,512a, 512b) of the OPA PIC (112, 132, 500a, 500b), the first signal based on the cross-coupling matrix.

This invention discloses a low-crosstalk mode-division multiplexing optical amplification device, comprising: a mode discrimination module, a beam combiner, a beam splitter, a monitoring module, and a few-mode semiconductor optical amplification module. The mode-division multiplexed signal to be amplified is split into two paths by a mode selection coupler. One path is coupled to a single-mode fiber with different mode coupling efficiencies and converted into an electrical signal, which is then sent to the monitoring module. Based on the signal level, the monitoring module identifies the mode combination information at different times in the input mode-division multiplexed signal and generates control light with corresponding power. The other path is still a mode-division multiplexed signal, which is input to the few-mode semiconductor optical amplification module along with the input signal through the beam combiner. After amplification, the output is sent to the beam splitter to separate the amplified control light and the mode-division multiplexed signal, which are used as the gain control signal and the output signal of the entire device, respectively. In this invention, the sum of the power of the controlled light and the power of the mode multiplexed signal to be amplified is always kept at the same level, so that the carrier concentration is always kept at the same level and the input signal gain at different times can be kept consistent, thereby effectively suppressing the cross-gain modulation effect, while amplifying the optical signals of multiple modes, and can also automatically adjust the mode gain, which can meet the needs of low crosstalk optical amplification modules in long-distance mode division multiplexing systems and mode division multiplexing switching nodes.