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.

An optical amplifier assembly and a detection method capable of dynamically performing optical time-domain reflection detection. The detection method comprises obtaining signal light intensity detection signals from a first and second photodetectors and sending a control signal to an L-band Raman pump when the signal light intensity in the second photodetector is lower than a first preset threshold, so that the L-band Raman pump enters into an optical time-domain reflection detection mode; sending a control signal to the L-band Raman pump when the signal light intensity in the second photodetector is greater than or equal the first preset threshold, so that the L-band Raman pump enters into an L-Band Raman optical fiber amplifier operation mode.

An objective of the present invention is to provide an amplification fiber having a cladding excitation configuration that improves amplification efficiency and an optical amplifier. An amplification fiber (10) according to the present invention is a multi-core amplification fiber having, from one end (E1) to the other end (EE), a plurality of cores (11b) in a cladding (11a), and a total distance from the one end (E1) to the other end (EE) in which rare earth ions are doped differs depending on the types of cores (11b). The cores (11b) are preferably disposed such that the cores of the same type are not adjacent to each other. By arranging the types of the cores in this manner, requirements for inter-core crosstalk can be mitigated since the bands of signal light in the adjacent cores are different. As a result, a density of cladding excitation light can be increased by shortening the inter-core distance, and thus the amplification efficiency can be improved.

An optical repeater is a C+L-band repeater inserted between a first transmission path fiber and a second transmission path fiber. The optical repeater includes: a first optical fiber amplifier inserted in a first line, for amplifying a C-band signal; a second optical fiber amplifier inserted in a second line, for amplifying an L-band signal; a third optical fiber amplifier inserted in a third line, for amplifying a C-band signal; a fourth optical fiber amplifier inserted in a fourth line, for amplifying an L-band signal; and a first loopback means provided between an input to the first optical fiber amplifier or an output from the first optical fiber amplifier and an input to the third optical fiber amplifier or an output from the third optical fiber amplifier.

An objective of the present invention is to provide an optical amplifier having a cladding excitation configuration that improves amplification efficiency. The optical amplifier includes an optical amplification unit 36 in which n (n is a natural number equal to or greater than 2) amplification fibers 34 that optically amplify signal light propagating through cores with excitation light supplied to claddings and n−1 optical input/output units 35 that input/output the signal light to/from the cores and the outside of the amplification fibers 34 are connected in series such that the amplification fibers 34 and the optical input/output units 35 are disposed in an alternating manner, an excitation light generator 31 that outputs the excitation light in multi-mode, and optical multiplexer/demultiplexers 33 that cause the excitation light from the excitation light generator 31 that has been divided into two light beams to be incident on the claddings of the amplification fibers 34 disposed at both ends of the optical amplification unit 36 and cause the signal light to be input to/output from the cores of the amplification fibers 34 disposed at both ends of the optical amplification unit 36.

A fiber optic ring laser, and non-transitory computer readable medium for using a fiber optic ring laser are disclosed. The disclosed fiber optic ring laser includes a semiconductor booster optical amplifier (BOA), as a gain medium; a Fiber Fabry Perot Tunable Filter (FFP-TF), as a wavelength selection element; an optical isolator (ISO) to insure unidirectional operation of the fiber optic ring laser; and a polarization controller (PC) for attaining an optimized polarization state in order to achieve a stable-generated output in terms of output power and wavelength, wherein the BOA, the FFP-TF, the ISO and the PC are coupled to form a ring configuration that implements a continuously tunable booster amplifier-based fiber ring laser.

An EDFA may include an input photodiode configured to generate a control signal based on an input signal. The EDFA may include a blind stage configured to generate an amplified signal based on the control signal and the input signal. The EDFA may include a non-blind stage configured to generate an output signal based on the amplified signal within the blind stage, the control signal, and a feedback signal. The EDFA may include a filter configured to generate a filtered signal based on the output signal. The EDFA may include an output photodiode configured to generate the feedback signal based on the filtered signal. The EDFA may include an alarm device. A signal within the non-blind stage may be generated based on the feedback signal and the control signal. The alarm device may be configured to generate an alarm signal when the signal exceeds a threshold value.

A fiber optic ring laser, and non-transitory computer readable medium for using a fiber optic ring laser are disclosed. The disclosed fiber optic ring laser includes a semiconductor booster optical amplifier (BOA), as a gain medium; a Fiber Fabry Perot Tunable Filter (FFP-TF), as a wavelength selection element; an optical isolator (ISO) to insure unidirectional operation of the fiber optic ring laser; and a polarization controller (PC) for attaining an optimized polarization state in order to achieve a stable-generated output in terms of output power and wavelength, wherein the BOA, the FFP-TF, the ISO and the PC are coupled to form a ring configuration that implements a continuously tunable booster amplifier-based fiber ring laser.

The present invention relates to the field of optical communication, and particularly to a balanced pumping L-band optical fiber amplifier comprising a first erbium-doped optical fiber, a second erbium-doped optical fiber, an absorbing erbium-doped optical fiber and at least two pumping lasers, the first erbium-doped optical fiber, the second erbium-doped optical fiber and the absorbing erbium-doped optical fiber being sequentially arranged in this order, and the at least two pumping lasers providing pumping light; wherein the first erbium-doped optical fiber and the second erbium-doped optical fiber both are injected with forward pumping light and backward pumping light, and the absorbing erbium-doped fiber is arranged downstream of the second erbium-doped optical fiber to absorb amplified spontaneous emission (ASE) generated in the amplifier. In the present invention, bidirectional pumping 1s applied in the first and last erbium-doped fibers in the optical path, and an erbium-doped optical fiber that has no pumping injection is added to absorb the ASE. Thus, the pumping conversion efficiency is greatly improved, the nonlinear four-wave mixing effect is reduced, and the problem that the L-band optical fiber amplifier has a high noise when utilizing the backward pumping 1s solved. Meanwhile, the noise figure and the manufacturing cost of the amplifier are reduced.

Systems and methods are provided for amplifying optical signals within one of two optical bands, such as C-band and L-band. An optical amplifying device, according to one implementation, may include a shared optical coil configured to propagate an optical signal. The optical amplifying device may further include a first junction configured to separate the shared optical coil into a first-band optical fiber and a second-band optical coil and a pump device configured to amplify the optical signal in the shared optical coil and the second-band optical coil. The first-band optical fiber may be configured to propagate the optical signal when the optical signal resides in a channel of a first plurality of channels within a first optical band. The second-band optical coil may be configured to propagate the optical signal when the optical signal resides in a channel of a second plurality of channels within a second optical band.