A fiber laser apparatus includes: an amplification optical fiber that amplifies a laser beam; one or more pumping light sources that generate pumping light that is supplied to the amplification optical fiber; an output optical fiber including a first core that allows the laser beam amplified by the amplification optical fiber to propagate therethrough, and a first cladding having a refractive index lower than a refractive index of the first core and surrounding a circumference of the first core; a delivery fiber including a second core optically coupled to the first core of the output optical fiber, and a second cladding having a refractive index lower than a refractive index of the second core and surrounding a circumference of the second core; and a first housing unit that houses the amplification optical fiber and the output optical fiber therein.

An optical fiber may include a core in which core-guided light generated by one or more light sources propagates along a length of the at least one optical fiber, one or more claddings, surrounding the core, to guide cladding-guided light generated by the one or more light sources along the length of the at least one optical fiber, and a reflector structure machined into the at least one optical fiber. The reflector structure may include multiple angled facets arranged at one or more respective angles relative to an axis of the optical fiber to reflect at least a portion of the core-guided light and/or the cladding-guided light passing through the optical fiber.

The technology of this application relates to an optical component constituting a fiber amplifier, a fiber amplifier, and a manufacturing method. The optical component is connected to a gain fiber by using a first fiber, or the optical component is directly connected to the gain fiber. The optical component is connected to one or more second optical components in the fiber amplifier by using a second fiber, and/or the optical component inputs an optical signal or outputs an optical signal amplified by the gain fiber by using the second fiber. Softening temperatures and/or refractive indexes of the first fiber and the second fiber are different, or softening temperatures and/or refractive indexes of the second fiber and the gain fiber are different.

The present invention makes it possible to improve excitation efficiency in a fiber laser device provided with a TFB having an injection optical fiber not connected to an excitation light source. This fiber laser device is provided with: a plurality of excitation light sources, at least one fiber bundle that injects excitation light from the plurality of excitation light sources from a plurality of injection optical fibers and couples the excitation light to one optical fiber; and a cavity that introduces the excitation light coupled by the fiber bundle and amplifies and emits laser light. The number of the plurality of injection optical fibers of the fiber bundle is larger than the number of the plurality of excitation light sources, and a loop part is configured by connecting surplus injection optical fibers to which the excitation light is not injected among the plurality of injection optical fibers of the fiber bundle.

Some embodiments may include a packaged laser diode assembly, comprising: a length of optical fiber having a core and a polymer buffer in direct contact with the core, the length of optical fiber having a first section and a second section, the first section of the length of optical fiber including a tip of an input end of the optical fiber, wherein the polymer buffer covers only the second section of the first and second sections; one or more laser diodes to generate laser light; means for directing a beam derived from the laser light into the input end of the length of optical fiber; a light stripper attached to the core in the first section of the length of optical fiber. Other embodiments may be disclosed and/or claimed.

An optically amplified repeater system includes optical transmission paths, a multi-channel optical amplifier, one or more Raman amplification pumping light sources, and a wavelength multiplexer. The multi-channel optical amplifier includes K simultaneous pumping light sources, N optical amplification media, and one or more optical couplers, and simultaneously amplifies, with the K simultaneous pumping light sources, light intensities of optical signals that pass through the N optical amplification media and propagate through the optical transmission paths. Light intensities of the wavelength band of the optical signals is Raman amplified by the Raman amplification pumping light. A light intensity of the Raman amplification pumping light output from the one or more Raman amplification pumping light sources is determined in accordance with characteristic differences between the optical signals passing through the optical transmission paths.

Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

The disclosure addresses the problem of increased optical insertion losses in integrated optical switches. It enables the implementation of an array of optical amplifiers, typically with low/moderate gain, to compensate for optical insertion losses in the integrated switches. The amplifier is based on a doped optical fiber which is optically pumped by a pump laser. The integrated optical switch includes a transposer that facilitates connectivity between a set of fibers and a photonic chip through an optical mode conversion. An all passive circuitry is built in a doped fiber amplifier, WDM couplers combine/separate the signals from the pump, and splitters allow sharing of a single pump by multiple amplifiers. In addition, switch pigtails are implemented with the doped fiber.

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.

Some embodiments may include a packaged laser diode assembly, comprising: a length of optical fiber having a core and a polymer buffer in direct contact with the core, the length of optical fiber having a first section and a second section, the first section of the length of optical fiber including a tip of an input end of the optical fiber, wherein the polymer buffer covers only the second section of the first and second sections; one or more laser diodes to generate laser light; means for directing a beam derived from the laser light into the input end of the length of optical fiber; a light stripper attached to the core in the first section of the length of optical fiber. Other embodiments may be disclosed and/or claimed.