A distributed antenna system comprises: one or more access units configured to receive multiple downlink radio frequency signal sets, and further configured to convert the multiple downlink radio frequency signal sets into multiple downlink optical signal sets; a first wavelength division multiplexing unit configured to multiplex the multiple downlink optical signal sets to generate a first wavelength division multiplexing optical signals; a first wavelength division demultiplexing unit configured to demultiplex the first wavelength division multiplexing optical signals to obtain the multiple downlink optical signal sets; a first optical fiber, coupled between the first wavelength division multiplexing unit and the first wavelength division demultiplexing unit, and configured to transmit the first wavelength division multiplexing optical signal; and multiple first remote units coupled to the first wavelength division multiplexing unit, and configured to convert the multiple downlink optical signal sets into the multiple downlink radio frequency signal sets for transmission.

An optical system (100) is described including: a reconfigurable optical device (103) with multiplexing wavelength division, comprising a plurality of actuators (A1-AN) and having associated a number of optical channels (M) and a number of degrees of freedom (N) lower than the number of optical channels; an optical stimulus source (106) connected to said reconfigurable optical device (103) to provide an optical stimulation signal (S.sub.in) having a wavelength band including a plurality of wavelengths associated with the optical channels; an optical-electric conversion device (200) configured to receive from said reconfigurable optical device (103) an optical monitoring signal (S.sub.out) corresponding to the optical stimulation signal (S.sub.in) and to provide a group of electrical signals of intensity (S.sub.EL1-S.sub.ELK) each representative of an intensity of the optical monitoring signal (S.sub.out) evaluated at a relative wavelength included in said band. The system also includes a control device (110) configured to control the plurality of actuators (A1-AN) according to said group of electrical signals (S.sub.EL1-S.sub.ELK) and according to a control law.

Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: OCM that detects optical power of each wavelength channel in second node; processor that controls optical power of each wavelength channel based on detection by OCM in first node; optical circuit that adjusts optical power of each wavelength channel based on control signal from the processor in first node; and second processor that decides whether the optical powers of wavelength channels have converged to target level based on detection by OCM. When the optical powers of wavelength channels have not converged to the target level, the processor controls the optical circuit using the control signal in first cycle. When the optical powers of wavelength channels have converged to the target level, the processor controls the optical circuit using the control signal in second cycle longer than first cycle.

A transmission device includes a wavelength multiplexer that wavelength-multiplexes a plurality of optical signals having different wavelengths to generate a wavelength-multiplexed optical signal, an amplifier that outputs the wavelength-multiplexed optical signal to a transmission path, and a first processor that allocates wavelength bands to the plurality of optical signals to be wavelength-multiplexed into the wavelength-multiplexed optical signal and controls power of the wavelength-multiplexed optical signal in accordance with the wavelength bands allocated to the plurality of optical signals.

This disclosure describes digitally generating sub-carriers (SCs) to provide isolation and dynamic allocation of bandwidth between uplink and downlink traffic between transceivers that are communicatively coupled via a bidirectional link including one or more segments of optical fiber. Separate uplink and downlink communication channels may be created using digitally generated SCs and using the same transmitter laser. In some implementations, one or more of the nodes include a transceiver having at least one laser and one digital signal processing (DSP) operable for digitally generating at least two SCs and detecting at least two SCs. The transceiver can transmit selected SCs, and can receive other SCs. Accordingly, the transceiver can facilitate bidirectional communication, for example, over a single optical fiber link. In some instances, techniques can facilitate dynamic bandwidth assignment by facilitating adding or blocking of optical subcarriers from transmission in an uplink or downlink direction.

One aspect of the present invention is a communication device including: a first control unit that converts, when data including partial data obtained by fragmenting a user frame and a user frame is received via a passive optical network, the partial data into data that is not discarded in a transmission line through which the user frame is transmitted, and transmits the data through the transmission line through which the user frame is transmitted; and a second control unit that receives the data via the transmission line through which the user frame is transmitted from the first control unit, converts the received data into a user frame that is transmittable through the passive optical network, and transmits the user frame via the passive optical network.

According to an example, a transmitter transmits a plurality of optical signals of multiple wavelengths via an optical link to a receiver. An optical link tuner coupled to the optical link groups the plurality of optical signals into a first group of optical signals and a second group of optical signals, where the first group of optical signals has a first wavelength range and the second group of optical signals has a second wavelength range. The optical link tuner adjusts link tuning parameters associated with the first group of optical signals during a first phase, such that the second group of optical signals is propagated to the receiver without modifications to link tuning parameters associated with the second group, where during the first phase the receiver is to detect unplugging of the optical link based on the second group of optical signals.

This disclosure describes devices and methods related to multiplexing optical data signals. A method may be disclosed. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to a first circulator. The method may also comprise combining, by the WDM, the second optical data signal and one or more third signals, and outputting an egress optical data signal to an optical switch. The method may also comprise outputing, by the optical switch, the egress optical data signal on a primary fiber.

This disclosure describes devices and methods related to multiplexing optical data signals. A method may be disclosed. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to a first circulator. The method may also comprise combining, by the WDM, the second optical data signal and one or more third signals, and outputting an egress optical data signal to an optical switch. The method may also comprise outputing, by the optical switch, the egress optical data signal on a primary fiber.

A light amplification device according to an example aspect of the invention includes a wavelength demultiplexing unit configured to demultiplex the wavelength division multiplexed signal light into a plurality of wavelength bands; a plurality of light amplification media configured to amplify the plurality of pieces of demultiplexed multiplex signal light; a wavelength multiplexing unit configured to multiplex the amplified demultiplexed multiplex signal light; a plurality of excitation energy supply units configured to supply excitation energy to each of the plurality of light amplification media; and a control unit, wherein the control unit includes a wavelength multiplexing/demultiplexing control unit configured to control the wavelength demultiplexing unit and the wavelength multiplexing unit in such a way that a starting wavelength and a wavelength number become an optimum starting wavelength and an optimum wavelength number when a sum of power consumption of the plurality of excitation energy supply units is minimized.