An optical system for controlling gain modification, including a first non-linear optical element (NLE) through which an input optical signal and a first pump wavelength are transmitted to generate a first optical signal; a second NLE through which the first optical signal is amplified to generate a second optical signal; a third NLE through which the second optical signal is amplified to generate a third optical signal; a first heating element coupled to the second NLE to adjust a temperature of the second NLE to control a first gain profile of the second optical signal; a second heating element coupled to the third NLE to adjust a temperature of the third NLE to control a second gain profile of the third optical signal, wherein the temperatures of the second and the third NLE minimize a gain modulation of the optical system based on the first and the second gain profiles.

It is difficult to construct an optical fiber transmission system enabling relay optical amplification using a coupled multi-core optical fiber as an optical transmission path; therefore, an optical amplification device includes first optical spatial layout converting means for converting a spatial layout of a plurality of optical signal beams propagating through each of a plurality of cores, from a coupled state in which optical signal beams interfere between a plurality of cores to a non-coupled state in which optical signal beam interference is reduced between a plurality of cores; optical amplifying means for amplifying, in the non-coupled state, the plurality of optical signal beams with the non-coupled state and generating a plurality of amplified optical signal beams; and second optical spatial layout converting means for converting a spatial layout of the plurality of amplified optical signal beams from the non-coupled state to the coupled state.

The technology of this application relates to an erbium-doped fiber. The erbium-doped fiber can be used in the fields of amplifiers, optical communications, rare-earth-doped fiber preparation, and the like. A fiber core of the erbium-doped fiber includes a first layer and a second layer from inside to outside. The first layer includes a center of the fiber core. The second layer is an annulus, and an outer ring of the annulus is an outer ring of the fiber core. An average doping concentration of erbium ions of the first layer is higher than an average doping concentration of erbium ions of the second layer. An ASE can be reduced by reducing a doping concentration of erbium ions of the second layer, to further reduce a noise figure of the erbium-doped fiber and improve communications quality.

An optical amplifier includes a first path and a second path, and an amplification unit that is arranged on one of the first path and the second path. The amplifier includes a first switch that is arranged on an input stage of the amplification unit, and that switches a third path that connects between the first path and the amplification unit or a fourth path that connects between the second path and the amplification unit. The amplifier includes a second switch that is arranged on an output stage of the amplification unit and that switches a fifth path that connects between the first path and the amplification unit or a sixth path that connects between the second path and the amplification unit. The first switch switches the third path over to the fourth path, and the second switch switches the fifth path to the sixth path.

A hybrid distributed amplification method based on a random fiber laser generated within erbium fiber with low doping concentration, i.e. weak erbium-doped fiber (WEDF), which includes: Step 1. constructing a fiber link via WEDF; Step 2. generating the random fiber laser based on the fiber link, the pump source, the wavelength division multiplexer and the strong feedback module; Step 3. constructing the spatial equalized gain based on hybrid gain of the erbium fiber and random fiber laser; Step 4. the signal is amplified by the hybrid spatial equalized gain. The present invention solves the typical problem of high laser threshold and low pump conversion efficiency when conventional fiber is used to generate random fiber laser for distributed amplification.

Disclosed is a submarine network device, comprising a fiber set, a pump laser set, an erbium doped fiber amplifier (EDFA) set, a primary fiber coupler (CPL) set and a secondary CPL set, wherein the primary CPL set comprises N primary CPLs, the secondary CPL set comprises N secondary CPLs, with N being an integer greater than or equal to 3. The fiber set is configured to connect the pump laser set, the primary CPL set, the secondary CPL set and the EDFA set. An input port of each primary CPL in the primary CPL set is at least connected with a pump laser. An output port of each secondary CPL in the secondary CPL set is at least connected with an EDFA. Output ports of each primary CPL in the primary CPL set are respectively connected with two different secondary CPLs that are spaced by a secondary CPL, and input ports of each secondary CPL in the secondary CPL set are respectively connected with two different primary CPLs that are spaced by a primary CPL.

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.

Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking. The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.

In an optical amplification device using a multicore optical fiber, it is difficult to efficiently amplify signal light. In order to solve this problem, an optical amplification device according to the present disclosure includes an optical fiber amplification unit including a plurality of amplification cores, a first connection unit being connected to one end of the optical fiber amplification unit, and a second connection unit being connected to another end of the optical fiber amplification unit, wherein the first connection unit is configured in such a way as to connect a transmission fiber including a plurality of transmission cores to the optical fiber amplification unit, and the number of the plurality of amplification cores is larger than the number of the plurality of transmission cores.

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 (?0) 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.