A bidirectional optical amplifier amplifies optical signals having signal wavelength and signal power input from two directions. The amplifier is arranged so that two counter-propagating signals pass through a first pumped rare earth doped pre-amplifier before passing through other amplifiers downstream. Optical circulators route the two counter propagating signals so that they both pass through in a counter-propagating manner through subsequent pumped rare earth doped amplifiers downstream.

A pluggable bidirectional optical amplifier module may include preamp and booster optical amplifiers and a housing. The preamp optical amplifier may be configured to amplify optical signals traveling in a first direction. The booster optical amplifier may be configured to amplify optical signals traveling in a second direction. The housing may at least partially enclose the preamp optical amplifier and the booster optical amplifier. The pluggable bidirectional optical amplifier module may have a mechanical form factor that is compliant with a pluggable communication module form factor MSA. A colorless mux/demux cable assembly may be operated with the pluggable bidirectional optical amplifier. The colorless mux/demux cable assembly may include a 1:N optical splitter a N:1 optical combiner coupled side-by-side to the 1:N optical splitter, a first fiber optic cable optic cable, and a second fiber optic cable.

Device and method for processing an optical signal. The device includes a photonic device arranged between a first input/output and second input/output and optically communicating with the inputs/outputs by a signal path for transmission of an optical signal in a first or second direction between the first input/output and second input/output. The device includes an optical gain element for amplifying the optical signal. The device includes a path switching circuit including a first signal amplification path connectable between the first input/output and the photonic device for optically coupling the signal path to and from the optical gain element, and a second signal amplification path connectable between the photonic device and the second input/output for optically coupling the signal path to and from the optical gain element. The path switching circuit selectively connects the first or second signal amplification path into the signal path.

A pluggable bidirectional optical amplifier module may include preamp and booster optical amplifiers and a housing. The preamp optical amplifier may be configured to amplify optical signals traveling in a first direction. The booster optical amplifier may be configured to amplify optical signals traveling in a second direction. The housing may at least partially enclose the preamp optical amplifier and the booster optical amplifier. The pluggable bidirectional optical amplifier module may have a mechanical form factor that is compliant with a pluggable communication module form factor MSA. A colorless mux/demux cable assembly may be operated with the pluggable bidirectional optical amplifier. The colorless mux/demux cable assembly may include a 1:N optical splitter a N:1 optical combiner coupled side-by-side to the 1:N optical splitter, a first fiber optic cable optic cable, and a second fiber optic cable.

Device (200,300) and method (500) for processing an optical signal. The device (200,300) comprises a photonic device (202,302) arranged between a first input/output (204,304) and a second input/output (206,306) and optically communicating with the inputs/outputs by a signal path (208,308) for transmission of an optical signal in a first or second direction between the first input/output (204,304) and the second input/output (206,306). The device (200,300) comprises an optical gain element (210,310) for amplifying the optical signal. The device (200,300) comprises a path switching circuit (212,312) comprising a first signal amplification path (214,314) connectable between the first input/output (204,304) and the photonic device (202,302) for optically coupling the signal path (208,308) to and from the optical gain element (210,310), and a second signal amplification path (216,316) connectable between the photonic device (202,302) and the second input/output (206,306) for optically coupling the signal path (208,308) to and from the optical gain element (210,310). The path switching circuit (212,312) is arranged to selectively connect the first signal amplification path (214,314) or the second signal amplification path (216,316) into the signal path (208,308).

A pluggable bidirectional optical amplifier module may include preamp and booster optical amplifiers and a housing. The preamp optical amplifier may be configured to amplify optical signals traveling in a first direction. The booster optical amplifier may be configured to amplify optical signals traveling in a second direction. The housing may at least partially enclose the preamp optical amplifier and the booster optical amplifier. The pluggable bidirectional optical amplifier module may have a mechanical form factor that is compliant with a pluggable communication module form factor MSA. A colorless mux/demux cable assembly may be operated with the pluggable bidirectional optical amplifier. The colorless mux/demux cable assembly may include a 1:N optical splitter a N:1 optical combiner coupled side-by-side to the 1:N optical splitter, a first fiber optic cable optic cable, and a second fiber optic cable.

A system includes (i) an optical link including multiple spans of optical fiber and multiple network elements and (ii) at least one switch configured to reverse a direction that at least one of the network elements communicates over the optical link.

A relay transmission system includes a relay unit configured to relay uplink signals and downlink signals in the first and second communication systems, a time division duplex (TDD) information estimation unit configured to estimate a transmission period of network devices in the first communication system on the basis of the uplink or downlink signal of the first communication system that is relayed by the relay unit, a surplus bandwidth determination unit configured to determine a surplus bandwidth in which an uplink signal of the first communication system is not allocated to a relay target of the relay unit during the transmission period on the basis of the number of network devices and a maximum transmission capacity of the network devices, and a bandwidth allocation unit configured to allocate the uplink signal of the second communication system to the relay target of the relay unit in the surplus bandwidth.

A free-space optical communication link is proposed that utilizes phase-sensitive amplification of the received optical signal at the input to the receiver portion of the link. The transmitter component of the FSO link generates an idler signal that is transmitted through free space with the original data signal and used at the PSA in conjunction with a pump wave to impart gain onto the received information signal. The PSA performs four-wave mixing (FWM) of the data, idler and pump to create the amplified data signal. In one embodiment, the pump wave used to generate the idler at the transmitter is sent through free space with the information and idler signals and used by the PSA to perform amplification. Alternatively, the PSA may use a co-located pump laser, in combination with the received idler signal, to perform the phase-sensitive amplification process.

A free-space optical communication link is proposed that utilizes phase-sensitive amplification of the received optical signal at the input to the receiver portion of the link. The transmitter component of the FSO link generates an idler signal that is transmitted through free space with the original data signal and used at the PSA in conjunction with a pump wave to impart gain onto the received information signal. The PSA performs four-wave mixing (FWM) of the data, idler and pump to create the amplified data signal. In one embodiment, the pump wave used to generate the idler at the transmitter is sent through free space with the information and idler signals and used by the PSA to perform amplification. Alternatively, the PSA may use a co-located pump laser, in combination with the received idler signal, to perform the phase-sensitive amplification process.