A coherent fiber array laser power projection system scalable to large number of subapertures and includes sensors that produce signals dependent upon beam characteristics, and controllers configured to control beam characteristics to achieve either phasing of outgoing beams at transmitter plane or coherent beam combining at a remote target or both.

Some embodiments may include a fiber laser including two or more input fibers and an output fiber to deliver a beam to a workpiece, the fiber laser comprising. The fiber laser may include a combiner having ends and a length, wherein the combiner is arranged to release, from its length, a portion of back-reflected light received from the output fiber at an output end of the ends from the combiner, the combiner including: a capillary tube to enclose part of the two or more input fibers at an input end of the ends of the combiner, the capillary tube having ends and a length located between the ends of the capillary tube; and a cladding light stripper (CLS) defined by part of the length of the capillary tube, wherein the CLS provides the release of the portion of the back-reflected light. Other embodiments may be disclosed and/or claimed.

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.

A photonic device is configured with a photonic integrated circuit (PIC), a plurality of fiber-based gain mediums in optical communication with the PIC, and at least one optical pump outputting pump light coupled into two or more gain mediums. At least one of the fiber-based gain media and the PIC form a hybrid resonant optical cavity there between operative to lase light into the PIC. The gain media further include one or more fiber amplifiers amplifying light signals coupled into and decoupled from the PIC. The photonic device is integrated with Si photonic passive and active photonic elements, while ail fiber links between the gain media and PIC are free from these elements.

A PIC has first, second and third elements fabricated on a common substrate. The first element includes a structure supporting efficient coupling of one or more free-space optical modes of incident light into one or more waveguide guided optical modes. The second element includes an on-chip interferometer having an input optically coupled to the waveguide guided optical modes; one or more arms; one or more outputs; and a phase tuner configured to change optical path length in one or more of the arms. The third element includes one or more light detecting structures optically coupled to the one or more outputs of the second element, such that variation in optical power in the one or more outputs is detected, allowing an assessment of coherence characterizing the light incident on the first element of the PIC to be provided.

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.

Aspects described herein include a method of fabricating an optical component. The method comprises electrically coupling different laser channels of a laser die to different electrical leads, testing a respective optical coupling of each of the different laser channels, optically aligning an optical fiber with a first laser channel of the different laser channels having the greatest optical coupling, and designating a second laser channel of the different laser channels as a heater element for the first laser channel.

Aspects described herein include a method of fabricating an optical component, the optical component, and a method of operating the optical component. A method includes electrically coupling a first laser channel and a second laser channel of a laser die to different electrical leads and testing (i) a first optical coupling of the first laser channel and a second optical coupling of the second laser channel or (ii) a first spectral performance of the first laser channel and a second spectral performance of the second laser channel. The method also includes optically aligning an optical fiber with the first laser channel and designating the second laser channel as a heater element for the first laser channel based at least in part on (i) the first optical coupling being greater than the second optical coupling or (ii) the first spectral performance relative to the second spectral performance

An ultra-compact, high power, fiber pump module apparatus has a heatsink with a stepped outer shape. The heatsink has at least one interior cooling channel. A plurality of single emitter diodes is positioned on one step of the stepped outer shape of the heatsink, respectively. At least two beam-shifting structures are positioned in a beam path of each of the plurality of single emitter diodes. The at least two beam-shifting structures fold each beam emitted from the plurality of single emitter diodes in at least three dimensions. At least one beam combining structure is positioned in the beam path, wherein the at least one beam combining structure combines the beams from each of the plurality of single emitter diodes into a single, combined beam. The single, combined beam is output from the ultra-compact, high power, fiber pump module apparatus.