The present disclosure relates to central units and remote units. One example central unit includes at least one digital-to-analog converter (DAC), at least one first electro-optical converter configured to convert an analog electrical signal output by the DAC into an analog optical signal, at least one first optical processor configured to process the analog optical signal output by the first electro-optical converter, where the first optical processor includes at least one of at least one first optical filter, at least one first optical phase shifter, and at least one first optical power amplifier, a first multiplexer configured to combine analog optical signals output by the first optical processor into one analog optical signal, and a first demultiplexer configured to decompose the one analog optical signal into multiple analog optical signals at different wavelengths.

Aspects described herein include an optical apparatus comprising a plurality of light-carrying media, a wavelength division multiplexing (WDM) device optically coupled with the plurality of light-carrying media, and a lens arranged between the WDM device and a multicore optical fiber. An arrangement of the plurality of light carrying media and the WDM device are selected to align each of the plurality of light-carrying media with a respective optical core of the multicore optical fiber.

Aspects described herein include an optical apparatus comprising a plurality of light-carrying media, a wavelength division multiplexing (WDM) device optically coupled with the plurality of light-carrying media, and a lens arranged between the WDM device and a multicore optical fiber. An arrangement of the plurality of light carrying media and the WDM device are selected to align each of the plurality of light-carrying media with a respective optical core of the multicore optical fiber.

Aspects of the subject disclosure may include, for example, receiving a first optical signal from a first optical network via a first port of the wavelength converter, receiving a second optical signal from a second optical network via a second port of the wavelength converter, modulating the first optical signal with the second light signal to generate a third optical signal, eliminating the first light signal from the third optical signal to generate a fourth optical signal, and transmitting the fourth optical signal through the second optical network. The first optical signal can include a first digital signal modulated onto a first light signal of a first wavelength, the second optical signal can include a second light signal can include a second wavelength different from the first wavelength, and the fourth optical signal can include the first digital signal modulated onto the second light signal. Other embodiments are disclosed.

This disclosure describes C and L band optical communications module link extender, and related systems and methods. An example method may include receiving, by a dense wave division multiplexer (DWDM) at a headend, one or more optical data signals over only an L band. The example method may also include combining the one or more optical data signals. The example method may also include outputting the combined one or more optical data signals to a first WDM at the headend. The example method may also include outputting, by a first WDM, the one or more optical data signals to an amplifier at the headend. The example method may also include amplifying, by the amplifier, the one or more optical data signals. The example method may also include outputting the amplified one or more optical data signals to a coexistence filter. The example method may also include outputting, by the coexistence filter, the amplified one or more optical data signals to an optical switch. The example method may also include outputting, by the optical switch, an egress optical data signal to a first fiber.

Provided is an optical transmitting and receiving system. The optical transmitting and receiving system may include: a Main Hub Unit (MHU) configured to perform wavelength division multiplexing on a plurality of downlink signals using a plurality of wavelengths and transmit the multiplexed downlink signal through a first optical cable; a first Remote Optical Unit (ROU) configured to perform demultiplexing on the multiplexed downlink signal received from the MHU and output a part of the plurality of downlink signals; and a second ROU configured to perform demultiplexing on the multiplexed downlink signal and output other part of the plurality of downlink signals.

The present disclosure relates to optical communications, and in particular, to a DWDM remote pumping system for improving an OSNR. The system includes remote pumping gain unit, preamplifier, and gain flattening filter sequentially connected. Remote pumping gain unit and the preamplifier are cascaded one behind the other as a whole amplifier. Gain flattening filter is disposed at the preamplifier's output end. In the system, the remote gain unit and preamplifier which have large impact on the OSNR of the entire system are optimally designed as a whole amplifier. In remote gain unit, gain flattening filter originally disposed between two erbium-doped fiber segments is moved back to preamplifier's output end for significant improvement of gain and noise figures of the remote gain unit while ensuring gain flatness of the entire transmission system, thus effectively improving the entire system's OSNR, improving operation stability and reliability, effectively reducing bit error rate, and facilitating system maintenance.

Provided are a next generation in-building relay system and method. The system includes: a 5G signal providing unit configured to down-convert a millimeter wave radio frequency signal to an intermediate frequency signal; a 5G master hub unit configured to convert the intermediate frequency signal into a radio over fiber (RoF) signal and transmit the RoF signal; an optical coupling unit configured to couple a digital optical signal output from a master hub unit and the analog optical signal output from the 5G master hub unit and transmit the coupled signal to an optical cable; and an optical distribution unit configured to separate the digital optical signal and the analog optical signal from the coupled signal, transmit the digital optical signal to a remote optical relay unit, and transmit the analog optical signal to distributed remote units.

An optical line terminal includes an optical comb generator, N downlink channels D.sub.k, and N uplink-photodetectors PD.sub.k. The optical comb generator is configured to generate a carrier signal having an optical-frequency-comb spectrum and including N optical tones T.sub.k and N optical tones R.sub.k, k={1, 2, . . . , N}. Each of the N downlink channels D.sub.k is optically coupled to the optical comb generator and is configured to generate a respective downlink signal DS.sub.k that includes optical tone T.sub.k modulated by downlink data. Each of the N uplink-photodetectors PD.sub.k is configured to receive a respective one of a plurality of modulated uplink signals US.sub.k, having optical tone R.sub.k as a carrier signal.

A distribution point unit to exchange communication data between a service provider and subscribers. The distribution point unit may include a first port to couple the distribution point unit to an optical data network to exchange communication data between the distribution point unit and the service provider, and a second port to couple the distribution point unit to an electrical data network to exchange the communication data between the subscribers and the distribution point unit. The distribution point unit may also include a third port to couple the distribution point unit to an electrical device, the third port being configured to provide control data to control the electrical device.