The present invention addresses the problem that, when an optical amplification device having a plurality of optical transmission paths, such as multi-core optical fibers, is used for bidirectional communication, it is difficult to construct an optical transmission system optimized for all of signal lights having different transmission directions. The optical amplification device of the present invention comprises: an optical guide means having a plurality of optical transmission paths including an optical amplification medium having a gain in the wavelength band of a signal light; an excitation light introducing means for introducing excitation light for exciting the optical amplification medium into the optical guide means from both ends of the optical guide means; and a residual excitation light introducing means for introducing residual excitation light output from both ends of the optical guide means and having a wavelength component of the excitation light into the optical guide means.

Systems and methods for optical amplifier failure prediction using Machine Learning (ML), such as for an Erbium-Doped Fiber Amplifier (EDFA), are described. A method include obtaining a plurality of inputs from an optical amplifier associated with an optical network; analyzing the plurality of inputs with a trained machine learning model; obtaining an estimate of a total pump current of the optical amplifier as an output of the trained machine learning model; and comparing the estimate of a total pump current to a measured total pump current of the optical amplifier. The steps can include determining a health of the optical amplifier based on the comparing

A laser pumping assembly includes a parallelepipedal solid laser medium having the shape of a plate in a horizontal plane (xy) and a thickness e.sub.L, the laser medium having an absorption spectral band and an associated absorption coefficient α; at least one light emission module intended to pump the laser medium, comprising a fluorescent parallelepipedal crystal called a concentrator, having the shape of a plate of thickness e.sub.c′, the concentrator having at least one illumination face illuminated by electroluminescent radiation and being configured to absorb the electroluminescent radiation and emit fluorescence radiation in a spectral range exhibiting an overlap with the absorption spectral band, the concentrator having an emitting face; the concentrator being in optical contact, via the emitting face, with a receiving face of the laser medium, the concentrator being arranged perpendicular to the laser medium such that the one or more illumination faces are perpendicular to the receiving face so as to perform transverse pumping of the laser medium, the optical contact being designed such that a portion of the fluorescence radiation trapped in the concentrator by total internal reflection is able to pass into the laser medium by passing through the emitting face, and be trapped in the laser medium by total internal reflection, the thickness e.sub.l of the laser medium being such that e.sub.L≤L.sub.abs/5 where L.sub.abs=1/α is an absorption length of the laser medium.

An optical fiber amplifier is formed to include a grating structure inscribed within the rare earth-doped gain fiber itself, providing distributed wavelength-dependent filtering (attenuation) and minimizing the need for any type of gain-flattening filter to be used at the output of the amplifier. The grating structure may be of any suitable arrangement that provides the desired loss spectrum, for example, similar to the profile of a prior art discrete GFF. Various types of grating structures that may be used to provide distributed wavelength-dependent filtering along the gain include, but are not limited to, tilted gratings, weak Bragg gratings, long-period grating (LPG), and any suitable combination of these grating structures.

An object is to provide an optical amplifier with a cladding pumped configuration that improves amplification efficiency. The optical amplifier according to the present invention includes a pump light conversion fiber 11 that converts first pump light L1 with a first wavelength propagating in a cladding into second pump light L2 with a second wavelength, an amplification fiber 13 that is connected to the pump light conversion fiber 11 and optically amplifies signal light Ls with the second pump light L2 supplied to the cladding from the pump light conversion fiber 11, and an oscillator 12 that causes the second pump light L2 to be reflected on two reflectors 15 and to reciprocate within the claddings of the pump light conversion fiber 11 and the amplification fiber 13 to cause laser oscillation of the second pump light L2.

Hybrid silicon devices are disclosed in which a silicon-based resonant structure is coated with a rare-earth-doped tellurium oxide layer that facilitates optical gain, thereby forming a silicon-based laser cavity. The silicon-based laser cavity supports at least one resonant mode that has a modal volume extending from the silicon resonant base structure into the rare-earth-doped tellurium oxide layer. The silicon-based laser cavity is optically coupled to a silicon waveguide to facilitate the delivery of pump laser energy to the silicon-based laser cavity, such that at least a portion of the pump laser energy propagating through the silicon waveguide is coupled to the silicon-based laser cavity for excitation of the rare earth dopant within the rare-earth-doped tellurium oxide layer. The silicon waveguide that is optically coupled to the silicon-based laser cavity also facilitates the external delivery of the laser energy generated within silicon-based laser cavity.

Disclosed are embodiments for multi-band pumping of a doped fiber source. The doped fiber source has a first absorption band and a second absorption band that is different from the first absorption band. In some embodiments, a first laser pump generates a first pump power in a first pump band corresponding to the first absorption band that is generated. A second laser pump generates a second pump power in a second pump band corresponding to the second absorption band. The second pump band is different from the first pump band. The first and second pump power is simultaneously applied to the doped fiber source.

There are provided a first cladding layer formed on a Si substrate, a first core made of Si and formed on the first cladding layer, and a second cladding layer formed on the first cladding layer and covering the first core Additionally, this optical device includes a waveguide type laser formed over the second cladding layer, a second core made of InP and formed continuously to the laser, and a third cladding layer formed on the second cladding layer and covering the laser and the second core.

Example optical amplification apparatus and example signal amplification methods are provided. One example optical amplification apparatus is connected to an optical fiber. The optical amplification apparatus includes a first pump laser and a first gain medium. The first pump laser is configured to emit first pump light. The first gain medium is configured to receive the first pump light and first multi-channel optical signals from the optical fiber; and perform gain amplification on the first multi-channel optical signals based on the first pump light, where the first pump light overlaps each of the first multi-channel optical signals in the first gain medium.

Multi-clad optical fiber cladding light stripper (CLS) comprising an inner cladding with one or more recessed surface regions to remove light propagating within the inner cladding. A CLS may comprise such recessed surface regions along two or more azimuthal angles about the fiber axis, for example to improve stripping efficiency. One or more dimensions, or spatial distribution, of the recessed surface regions may be randomized, for example to improve stripping uniformity across a multiplicity of modes propagating within a cladding. Adjacent recessed surface regions may abut, for example, end-to-end, as segments of a recess that occupies a majority, or even an entirety, of the length of a fiber surrounded by a heat sink. One or more dimensions, or angular position, of individual ones of the abutted recessed surface regions may vary, according to a regular or irregular pattern.