In order to solve the problem that the power consumption of optical amplifiers is not optimized over the life time of a network whose capacity in use varies, an optical amplifier according to an exemplary aspect of the invention includes a gain medium for amplifying a plurality of optical channels, the gain medium including a plurality of cores through which the plurality of optical channels to propagate respectively and a cladding area surrounding the plurality of cores; monitoring means for monitoring the plurality of optical channels inputted into the gain medium and producing a monitoring result; a first light source configured to emit a first light beam to excite the cladding area; a second light source configured to emit a plurality of second light beams to excite each of the plurality of cores individually; and controlling means for making a decision as to whether each of the plurality of cores to transmit one of the plurality of optical channels based on the monitoring result, and controlling the first light source and the second light source based on the decision.

Disclosed is a method of Controlling a gain of an optical amplifier comprising a gain medium and at least one pumping device. The method comprises the following steps: determining or predicting a change of input signal power to the amplifier, changing the pump power from an initial pump power level to a new pump power level at a first time instant, the initial pump power level being the pump power level applied to the amplifier prior to the change in input signal power, setting the pump power to a second pump power level at a second time instant, wherein the pump power level is varied in an oscillatory manner for at least one period of time starting at a third time instant and ending at a fourth time instant, wherein said third time instant is identical with or later than said first time instant and said fourth time instant is identical with or earlier than said second time instant.

Bismuth (Bi) doped optical fibers (BiDF) and Bi-doped fiber amplifiers (BiDFA) are shown and described. The BiDF comprises a gain band and an auxiliary band. The gain band has a first center wavelength (λ1) and a first six decibel (6 dB) gain bandwidth. The auxiliary band has a second center wavelength (λ2), with λ2>λ1. The system further comprises a signal source and a pump source that are optically coupled to the BiDF. The signal source provides an optical signal at λ1, while the pump source provides pump light at a pump wavelength (λ3).

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.

An optical fiber securing structure includes: an optical fiber including a coating, and a coating-removed section in which a partial section of the coating is removed from the optical fiber; a reinforcement member including main surfaces and a groove formed from one of the main surfaces toward an inside of the reinforcement member, where the groove has a pair of side walls and a bottom wall; and a resin member that secures the coating-removed section to the pair of side walls and the bottom wall. A bottom part of the groove that includes the bottom wall has a widthwise cross-sectional shape where the bottom wall constitutes a trapezoidal shape such that a distance between the pair of side walls becomes greater in a direction away from the bottom wall.

A bi-directionally pumped PM fiber amplifier includes an amplifier input coupled to a first WDM coupler and a second WDM coupler providing an amplifier output. A doped fiber is between the WDM couplers. A first pump light source emitting at a first wavelength along a first polarization axis is coupled to the WDM coupler through a polarization beam combiner/splitter and a polarization rotator is for downstream pumping of the doped fiber with rotated light relative to the first polarization. The fiber is upstream pumped with light having the first polarization using a second pump light source emitting at the first wavelength/first polarization, by an output of an optical power splitter with its input coupled to the first pump light source, or by a fiber-coupled rotator mirror coupled to the second WDM coupler.

The optical amplifier, which amplifies wavelength multiplexed signal light, comprises: a multi-core optical fiber which includes cladding and a first core and a second core disposed in the cladding, and which is doped with rare-earth ions; an excitation light source for supplying excitation light to the cladding of the multi-core optical fiber; and a wavelength demultiplexing means for separating the wavelength bands of the wavelength multiplexed signal light that has propagated through the first core. The signal light of a relatively long wavelength band among a plurality of wavelength bands separated by the wavelength demultiplexing means is caused to propagate through the second core, and is then multiplexed with the signal light of a relatively short wavelength band among the plurality of wavelength bands separated by the wavelength demultiplexing means, and the resultant multiplexed signal light is output.

An amplifier operable with an electric drive signal can amplify signal light having a signal wavelength. A laser diode has an active section with input and output facets. The facets are in optical communication with the signal light and are configured to pass the signal light through the laser diode. The active section is configured to generate pump light in response to injection of the electrical drive signal into the active section. The pump light has a pump wavelength different from the signal wavelength. A doped fiber doped with an active dopant is in optical communication with the signal light and is in optical communication with at least a portion of the pump light from the laser diode. The pump wavelength of the pump light is configured to interact with the active dopant of the fiber and thereby amplify the signal light.

Low wavelength infrared Super Continuum (SC) signals from a master oscillator seeds an amplifier that supports the Raman effect. Counter-propagating, high-power, continuous wave, and quasi-continuous wave quantum cascade lasers pumps (amplify) the optical seeds forming multiple coherent wavelength optical pump sources.

An optical amplification device includes a first Raman amplifier outputs a first excitation light to a transmission line in a same direction as a signal light, and a second Raman amplifier outputs a second excitation light to the transmission line in an opposite direction to the signal light. The first Raman amplifier includes a first detector detects a first power of a first transmitted light transmitted through a first optical filter. The second Raman amplifier includes a second detector detects second power of a second transmitted light transmitted through a second optical filter. The first Raman amplifier stops output of the first excitation light when the first power is higher than a threshold. The second Raman amplifier stops output of the second excitation light when the second power is reduced from power of the first excitation light transmitted through the second optical filter.