An optical amplifying fiber includes: at least one single core portion doped with a rare-earth element; an inner cladding portion configured to enclose the at least one core portion, the inner cladding portion having a lower refractive index than maximum refractive index of each core portion; and an outer cladding portion configured to enclose the inner cladding portion, the outer cladding portion having a lower refractive index than refractive index of the inner cladding portion, wherein the inner cladding portion includes a plurality of air bubbles.

A fiber applied to an optical amplifier, where the fiber includes a rare earth-doped core and a cladding. The core includes a gain equalization unit. The core is configured to separately amplify optical signals of all wavelengths in a received multiplexing wave. The gain equalization unit is configured to equalize gains of the optical signals of all the wavelengths, such that gains of optical signals that are of all the wavelengths and that are transmitted from an egress port of the fiber all fall within a preset range, The gain of the optical signal of each wavelength in the optical signals of all the wavelengths is determined based on a ratio of power of an amplified optical signal to power of the unamplified optical signal.

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 amplifier includes one or more rare earth element-doped optical fibers each including one or more cores, two or more excitation light sources per single core of the one or more rare earth element-doped optical fibers, configured to emit excitation light for exciting a rare earth element added to the one or more rare earth element-doped optical fibers according to a driving current, and a synthesizing part configured to synthesize the excitation light emitted from the two or more excitation light sources per single core. Two or more cores are provided in total, and the excitation light emitted from the two or more excitation light sources per single core is synthesized and input with respect to each core.

Disclosed are a control method and an optical fiber amplifier. The optical fiber amplifier is configured to execute the control method. The method comprises: initially correcting a target gain on the basis of a first compensation gain to obtain an initially corrected target gain; when the actual power of the pump laser reaches target power determined on the basis of the initially corrected target gain obtaining, on the basis of a first signal optical power and a second signal optical power, a second compensation gain and a first compensation slope through calculation; correcting the initially corrected target gain again according to the second compensation gain to obtain a corrected target gain; and correcting a target slope according to the first compensation slope to obtain a corrected target slope. This solution can provide high precision control for the gain and the slope of the optical fiber amplifier.

A plastic optical fiber communication system includes a light source that emits a first signal having a first wavelength in a visible light spectrum, the first signal being encoded with information at a high data-rate of 0.1 to 10 Gbit/s; a pump laser system that emits a pump laser light having a second wavelength, different from the first wavelength; a perovskite-doped optical fiber excited by the pump laser light to generate an amplified spontaneous emission spectrum that encompasses the first wavelength so as to receive and amplify the first signal for generating an amplified output signal having the first wavelength; and a photodetector optically coupled to the perovskite-doped optical fiber, and configured to receive the amplified output signal at the high data-rate of 0.1 to 10 Gbit/s. The amplified output signal is encoded with the information.

An object is to provide an optical repeater that improves the fault tolerance of a plurality of excitation light sources while sharing the excitation light sources among a plurality of optical fibers. An optical repeater (100) includes excitation light sources (S1-S5), optical amplification units (A1-A5), and an optical distribution unit (10). The optical amplification units (A1-A5) amplify optical signals by using lights output from the excitation light sources (S1-S5). The optical distribution unit (10) includes a plurality of optical multiplexing/demultiplexing units. The optical distribution unit (10) is configured in such a manner that the lights from the four different excitation light sources in the excitation light sources (S1-S5) to be input to each of the light amplification units (A1-A5).

A system and method for efficient optical signal amplification with system monitoring features are provided. For example, an optical repeater may include two different 4-port thin-film gain flattening filters (TF-GFFs), which may be connected to provide a high-loss loop-back (HLLB) path in the optical repeater for system monitoring. The 4-port TF-GFF may have four different ports and may integrate the functionalities of a conventional GFF and a coupler into a single component, thereby increasing power efficiency of the optical repeater.

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.

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.