An optical amplifier may include an optical fiber to propagate a forward optical signal in a path of propagation of the optical amplifier. The optical fiber may have an input end face that is angled non-perpendicular to the path of propagation. The optical amplifier may include an optical component, in optical communication with the input end face of the optical fiber, to direct a backward optical emission away from the path of propagation.

An optical fiber includes a core and a cladding. An effective area A.sub.eff of light of a fundamental mode, having a wavelength of 1070 nm and propagating through the core, is 500 μm.sup.2 or more. A numerical aperture NA of the core satisfies the following formula:

NA≥(1.3×10.sup.−11×a.sup.4/b.sup.6).sup.1/6

where a (m) is a radius of the core and b (m) is a radius of the cladding. A V value, that is a waveguide parameter of the optical fiber, satisfies the following formula:

V≤1.3583×b.sup.−0.2555.

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 optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

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.

There is described a fiber laser system generally having a pump laser generating a pump laser beam; and a length of optical fiber optically coupled to the pump laser, the length of optical fiber having: a laser cavity having a cavity path, a first fiber Bragg grating having a first reflectivity profile, a second filter having a second filter profile, and an optical gain region between the first fiber Bragg grating and the second filter along the cavity path, the first reflectivity profile being spectrally detuned from the second filter profile, the first fiber Bragg grating having a first refractive index profile comprising a full width at half maximum bandwidth of at least 0.2 nm and a Gaussian-like apodization, wherein, upon pumping of the optical gain region with the pump laser beam and mode locking of the laser cavity, optical pulses are circulated along the cavity path; and an output.

The present disclosure generally relates optical amplifier modules. In one form for example, an optical amplifier module includes a booster optical amplifier configured to increase optical power of a first optical signal. The module also includes a preamp optical amplifier configured to increase optical power of a second optical signal and a pump laser optically coupled to the booster optical amplifier and the preamp optical amplifier. The pump laser is configured to provide a booster power to the booster optical amplifier and a preamp power to the preamp optical amplifier, the preamp power is effective to induce a gain in optical power to provide a target optical power of the second optical signal from the preamp optical amplifier, and the booster power is dependent on the preamp power.

A multiple stage optical amplification device in a light detection and ranging (LiDAR) scanning system is provided. The system comprises a first power amplification stage receiving seed laser light and outputting first amplified laser light; a second power amplification stage receiving the first amplified laser light and outputting a second amplified laser light; and a single optical power pump coupled to the second power amplification stage. The second power amplification stage is configured to amplify the first amplified laser light to generate the second amplified laser light. A first portion of pump power provided by the optical power pump is deliverable to the first power amplification stage to amplify the seed laser light.

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.