Abstract: Methods, systems, and devices are disclosed for using optical modes in optical waveguides to carry different optical communication signals. In one aspect, an optical device for optical MDM in optical communications includes an optical waveguide configured to support multiple optical waveguide modes and to carry light of different optical communication channels in different optical waveguide modes, respectively, of the multiple optical waveguide modes. The optical device includes an optical resonator configured to be capable of carrying an optical communication channel in one optical resonator mode and optically coupled to the optical waveguide to selectively couple the optical communication channel in the optical resonator into the optical waveguide to add a channel into the optical waveguide via optical mode division multiplexing. In another aspect, an optical mode division demultiplexing can be performed by coupling an optical waveguide and an optical resonator.

Abstract: A mode-multiplexing control method, and a transmission apparatus and reception apparatus for the same, the mode-multiplexing control method performed by the transmission apparatus, the mode-multiplexing control method including measuring data traffic, determining a transmission mode count to be used based on the measured data traffic, and transmitting data to a reception apparatus through an optical line in transmission modes corresponding to the determined transmission mode count.

Abstract: A remote radio head disposed between a baseband unit and a host unit. The remote radio head may transmit and receive a digital optical signal to the baseband unit, transmit and receive an analog optical signal to the host unit, and convert the digital optical signal and the analog optical signal, a frequency of the analog optical signal transmitted and received by the remote radio head and the host unit may be an intermediate frequency of a baseband, the host unit may be disposed between the remote radio head and a radio unit, the host unit and the radio unit may transmit and receive the analog optical signal, and the frequency of the analog optical signal transmitted and received by the host unit and the radio unit may be the intermediate frequency with a baseband signal.

Abstract: There is provided a method of transmitting a visible light signal in visible light communication, including binarizing data to be transmitted into a binary bit representation, encoding the data for transmission by modulating one or more of a plurality of light emitting regions between a first state and a second state based on the binary bit representation of the data, and transmitting the visible light signal in the form of light emitted by one or more of the plurality of modulated light emitting regions, the visible light signal being decodable to obtain the data. There is also provided a method of transmitting a visible light signal in visible light communication which includes modulating one or more second sets of light emitting regions within the capture region between a first state and a second state based on the bit representations of one or more previous data for enabling error detection. Corresponding methods of receiving a visible light signal and systems are also provided.

Abstract: The present disclosure relates to a method for decoding a combined AM/FM encoded signal, comprising the steps of: combining said encoded optical signal with light from a local oscillator configured with a local oscillator frequency; converting the combined local oscillator and encoded optical signal into one or more electrical signals by means of at least one opto-electrical converter having a predefined frequency bandwidth, thereby providing an amplified and encoded electrical signal having one or more encoded signal current(s), where one type of states have a higher oscillation frequency than other type of states; rectifying the encoded signal current(s), thereby obtaining an encoded power spectrum, wherein said power spectrum has different states, such as “0”-states and “1”-states, with different power levels such that they can be discriminated, said local oscillator frequency is defined by a positive local oscillator frequency-offset from the frequency of one of the states in said encoded optical signal,

Abstract: A digital instruction is generated regarding one or more electrical-to-optical conversion impairments induced at the transmitter of an optical communication system. The digital instruction may be used by the transmitter to reduce the impairments. Alternatively, or additionally, the digital instruction may be used by the receiver of the optical communication system to compensate for the impairments.

Abstract: An optical transmitter includes an optical modulator configured to modulate an optical signal, a dual-stage space switch configured to receive, as an input, the modulated optical signal from the optical modulator, and output ports configured to control light outputs based on an operation of the dual-stage space switch.

Abstract: A bidirectional optical element in optical network units (ONUs) of a passive optical network (PON) includes a main filter configured to pass an upstream signal having an upstream-channel wavelength and a downstream signal having a downstream-channel wavelength, a drop filter configured to pass the downstream signal having the downstream-channel wavelength and reject the upstream signal having the upstream-channel wavelength, and an add filter configured to pass the upstream signal having the upstream-channel wavelength and reject the downstream signal having the downstream-channel wavelength, wherein the main filter, the drop filter, and the add filter are configured to share a single optical waveguide, and the optical waveguide is configured to connect input ports of the main filter and the drop filter and an output port of the drop filter and is provided in a straight line shape.

Abstract: A Data Over Cable Service Interface Specifications (DOCSIS) Passive Optical Network (PON) system (DPON) makes optical subscribers appear as cable subscribers. In one embodiment, a Cable Modern (CM) proxy is located in an Optical Line Termination (OLT). The OLT implements a cable modem protocol stack that operates as the CM proxy and communicates with a back office system. The OLT translates the data retrieved by the CM proxy into Optical Network Unit (ONU) recognizable commands, and sends the translated data to the ONU. In a second embodiment, the CM proxy is located in the ONU. The ONU implements the cable modern protocol stack that operates as the CM proxy and communicates with the back office system. The ONU translates the data retrieved by the CM proxy into ONU recognizable commands and sends the translated data to the ONU.

Abstract: Embodiments of the present invention provide a method and an apparatus for transmitting and receiving a client signal, and relate to the field of communications technologies. The method includes mapping the client signal into channels of a parallel transmission frame, where the parallel transmission frame includes at least two channels; adding an overhead for the channels of the parallel transmission frame after the mapping, to form transmission channels of the parallel transmission frame, where bit rates of the transmission channels of the parallel transmission frame are fixed; and modulating the transmission channels of the parallel transmission frame onto one or more optical carriers in a same optical fiber, and transmitting the optical carrier after the modulation.

Abstract: A fiber optic network (10) includes a mobile switching center (MSC) (12) which distributes fiber optic signals to one or more remote cabinets (40, 42, 44). The remote cabinets (40, 42, 44) distribute signals to one or more customers. The cabinets (40, 42, 44) receive service from the MSC (12) or from a temporary service provider, such as a vehicle (500), in the event of a catastrophic failure of the MSC (12). The cabinets (40, 42, 44) include equipment which allows patching to a temporary service provider through a patch panel (200), and sub-racks (154, 156, 158) and supporting cabling (134, 136) to provide service to each of the cabinets in the network.

Abstract: A bidirectional data communications cable is disclosed. The cable includes first connector, second connector, and cable housing coupled to the first and second connectors. The first connector includes a controller configured to determine whether the first connector is connected to a data source or data sink. If connected to a data source, the controller configures a switch circuit to route a data signal from the data source to an optical modulator for modulating an optical signal for transmission from the first to the second connector via an optical fiber. If connected to a data sink, the controller configures the switch circuit to route a data signal from an optical demodulator to the data sink, the optical demodulator receiving an optical signal modulated with the data signal from the second connector via an optical fiber. The second connector is configured similar to the first connector. The cable housing encloses the optical fibers.

Abstract: In some embodiments, a non-transitory processor-readable medium storing code representing instructions to be executed by a processor comprises code to cause the processor to determine, during a calibration of a coherent optical transmitter, a set of parameters associated with each tributary channel by sending a first signal to a digital signal processor (DSP) to adjust a scale factor of that tributary channel. The scale factor is associated with a tap characteristic of a finite impulse response (FIR) filter of the DSP. The code further causes the processor to determine a power imbalance between two tributary channels based on the set of parameters associated with each tributary channel. The code further causes the processor to send a second signal to the coherent optical transmitter to adjust a set of operational settings of the coherent optical transmitter based on the power imbalance and the set of parameters associated with each tributary channel.

Abstract: The present disclosure discloses a method for eliminating nonlinear effects, a transmitter and a receiver. The method includes: setting signals to be transmitted and redundant signals, where the redundant signals are symmetrical to the signals, which are to be transmitted, about Y axis; and after the setting is completed, respectively executing dispersion pre-compensation on the signals to be transmitted and the redundant signals, and executing signal modulation after the dispersion pre-compensation is completed.

Abstract: A method may include causing a signal to be transmitted that includes a plurality of wavelengths. The signal may be transmitted via an optical fiber that is associated with a particular wavelength. The particular wavelength may be included in the plurality of wavelengths. The method may include filtering the signal, based on the particular wavelength, to generate a filtered signal. The filtered signal may include the particular wavelength. The method may include detecting the filtered signal in association with the optical fiber. The method may include determining the particular wavelength based on the filtered signal. The method may include storing or providing information identifying at least one of the particular wavelength, the optical fiber, or a transmitter that transmitted the signal.

Abstract: A method is provided for detecting intrusion into optical fibers of a Passive Optical Network (PON) of the type which includes a multiplexing system at the head end for separating a data signal output at the head end to the plurality of fibers for supply to user end terminals and a data transmission system at each of the user end terminals for entering onto the fiber data as an optical signal. The method includes providing a monitor system having a transmitter at the head end and a monitor signal analysis system for analyzing changes in the optical monitor signal after transmission along the fiber for detecting an intrusion event. A monitor signal analysis system is provided at one or more user end terminals for detection and conversion of data from the analysis into a digital signal which is then transmitted from the user end terminals back to the head end using the data transmission system through the PON system or separately from the PON system.

Abstract: An optical carrier selector system is provided for selecting a wanted carrier signal from a multi-carrier signal comprising a plurality of carrier signals. The optical carrier selector system comprises a series of optical filter devices. Each optical filter device of the series comprises an input port for receiving a signal comprising two or more carrier signals, each optical filter device being configured to filter out an unwanted carrier signal. Each optical filter device also comprises an output port for outputting at least the wanted carrier signal and any remaining signals that have not been filtered out by that particular optical filter device, and a drop port for outputting the unwanted carrier signal that is being filtered out by the respective optical filter device.

Abstract: A system for reducing the cost and increasing the rate and reliability of data transmission from space to ground includes a network of relay satellites in low Earth orbit (LEO). Each relay satellite is configured to receive data from one or more client satellites, and configured to transmit data from LEO to ground using optical communications. The system may also include multiple optical ground stations configured to receive the data and transmit the received data using terrestrial networks to client locations. The network may provide an alternative to downlinking large amounts of data for new satellite operators without an existing ground network and for established satellite operators seeking higher data rates, lower latency, or reduced ground system operating costs.

Abstract: A method of determining a path in an optical server network (31) comprises obtaining an indication of an amount of premium traffic from a client network (21). The method further comprises considering paths (48) utilising an elastic capability of one or more network elements (30) of the optical server network, and selecting a path from the considered paths, wherein the path is selected based at least partially on having at least a capacity to carry the amount of premium traffic.

Abstract: A method decodes an optical signal transmitted over an optical channel from a transmitter to a receiver. The receiver receives the transmitted optical signal to produce a digital signal which is filtered in the frequency domain for compensating static effects and/or dynamic effects. The filtering is performed in the frequency domain, while the frequency coefficients of the filter are updated in the time domain by updating at least some of time coefficients of the filter and transforming the time coefficients into the frequency domain.