Provided are optical communication signal recovery techniques and a submarine optical communication recovery device may include a number of inputs, a number of outputs and a number of optical switch modules. Each input may be operable to connect to a respective optical fiber of a submarine fiber optic cable, and a number of the optical fibers carry optical signals and at least one optical fiber of the plurality of optical fibers is an unusable optical path that is unable to carry a usable optical signal. Each output may couple to another respective optical fiber, and a number of the outputs may be designated as impaired outputs. Each optical switch module of the number of optical switch modules may be operable to connect an input of the number of inputs coupled to the unusable optical path to an impaired output of the number of the impaired outputs.

A system (e.g., an optical amplifier) comprising gain fibers (e.g., Bismuth-doped optical fiber) for amplifying optical signals. The optical signals have an operating center wavelength (λ0) that is centered between approximately 1260 nanometers (˜1260 nm) and ˜1360 nm (which is in the O-Band). The gain fibers are optically coupled to pump sources, with the number of pump sources being less than or equal to the number of gain fibers. The pump sources are (optionally) shared among the gain fibers, thereby providing more efficient use of resources.

A cyclic wavelength band permutation device (31) includes as many wavelength band converters (32a to 32c) as the wavelength bands of optical signals (S1, C1, and L1), and the wavelength band converters are individually connected to the output terminals of corresponding optical amplifiers among a plurality of optical amplifiers (17a to 17c) connected to an optical fiber (16) in an inserted manner. When a wavelength-multiplexed signal beam obtained by multiplexing optical signals in different wavelength bands is multiband-transmitted through an optical fiber while being amplified by the plurality of optical amplifiers, each wavelength band converter performs a cyclic permutation process of transitioning or converting an optical signal allocated to the shorter wavelength band side in the bands of the optical fiber to the longer wavelength band side, and also transitioning or converting an optical signal allocated to the longest wavelength band to the shortest wavelength band.

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.

An optical communication system having an optical transmission line, where a first section of the optical transmission line is connected to a first optical communication device; and a second section of the optical transmission line is connected to a second optical communication device. The optical communication system further includes: a Raman light source; an incident device connected to same end of the second section of the optical transmission line as the second optical communication device; and a separating device interconnecting the first section of the optical transmission line to the second section of the optical transmission line. The incident device causes excitation light output from the Raman light source to be incident to the second section of the optical transmission line and performs distributed Raman amplification on the optical signal; and the separating device separates the excitation light that is caused to be incident by the incident device.

An optical communication system having an optical transmission line, where a first section of the optical transmission line is connected to a first optical communication device; and a second section of the optical transmission line is connected to a second optical communication device. The optical communication system further includes: a Raman light source; an incident device connected to same end of the second section of the optical transmission line as the second optical communication device; and a separating device interconnecting the first section of the optical transmission line to the second section of the optical transmission line. The incident device causes excitation light output from the Raman light source to be incident to the second section of the optical transmission line and performs distributed Raman amplification on the optical signal; and the separating device separates the excitation light that is caused to be incident by the incident device.

An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

An apparatus includes a remote optically pumped amplifier (ROPA). The ROPA includes a bypass filter configured to receive an optical signal and first pump power and to separate the optical signal and the first pump power. The ROPA also includes an amplifier configured to receive the optical signal from the bypass filter and to amplify the optical signal. The ROPA further includes an optical combiner/multiplexer configured to receive the first pump power from the bypass filter, receive at least second and third pump powers, combine at least two of the first, second and third pump powers, and provide different pump powers or combinations of pump powers to different locations within the ROPA to feed the amplifier.

A method and system for amplifying optical signals includes generating idler signals for input signals using an optical pump at a first non-linear element (NLE). An intermediate stage including a Raman amplifier performs pump amplification using the output from the first NLE along a single optical path. Optical power monitoring of the input signals may be used for power equalization. The intermediate stage may include a wavelength selective switch for a certain degree of phase modulation. The phase-sensitive amplified signal is generated at a second NLE using the optical pump. Optical power monitoring of the input signals may be used for power equalization and other control functions to achieve low-noise operation.