Abstract: An optical pedestal fiber is configured to be taperable to form a tapered fiber having a mode field diameter at the tapered end that differs from the mode field diameter at the untapered end in correspondence with the difference between the cladding diameter at the tapered end and the cladding diameter at the untapered end. A plurality of such pedestal fibers can be used to construct a tapered fiber bundle coupler that provides matching of both core pitch and mode field diameter between a plurality of input fibers and individual cores of a multicore fiber. Further, the tapered fiber bundle coupler can be constructed using a plurality of fibers, in which individual fibers are configured to have different effective refractive indices, thereby suppressing crosstalk therebetween.

Abstract: Apparatus and method of simultaneously measuring a parameter of a plurality of cores in at least one optical fiber. An input tester at a first end of the test fiber has a plurality of tester signal inputs with a geometry substantially matching at least a portion of the core geometry of the fiber. At least one test input signal source coupled to the plurality of tester signal inputs. A signal measuring device is alignable at a second end of the fiber to measure the output of the test input signal. The input tester may include a tapered multicore coupler or a laser having a shield with apertures disposable between the laser and the fiber. In the latter case, a lens may be disposed between the shield and the fiber to project light from the laser that passes through the apertures onto the end of the fiber.

Abstract: Described is a general strategy of bend-compensated, single-mode LMA fibers extended into a regime with higher total index contrast and where a larger gradient is used to cancel the perturbation of a tighter anticipated bend.

Abstract: The cladding absorption of single-mode, double-clad, gain-producing fibers is increased in fiber designs that includes a trench region disposed between the core and inner cladding regions. Increased cladding absorption is achieved while maintaining single-mode operation.

Abstract: The cladding absorption of a single-mode, gain-producing fibers is increased in fiber designs that includes a trench region disposed between the core and inner cladding regions. Increased cladding absorption is achieved while maintaining single-mode operation.

Abstract: A tapered fiber bundle (TFB) with a brightness reduction (R) that is between 0 and approximately 0.65 (or 65%), where R=(1?(di/da)2), di is an ideal output diameter, and da is an actual output diameter. The TFB is optically coupled to a gain fiber with a mode field diameter (MFD) that is between approximately 13 micrometers and approximately 25 micrometers.

Abstract: Embodiments of the present invention generally relate to laser combiners, and more specifically, to all-fiber devices that combine optical laser power from multiple separate sources such as lasers or amplifiers. In one embodiment, a method of manufacturing a combiner device comprises: positioning an plurality of fibers into a bundle of fibers; drawing the bundle of fibers to create a tapered section, the tapered section having a first outer diameter at an input end, a second outer diameter at an output end, and a taper ratio of at least three; wherein at least one of the fibers of the bundle of fibers comprises an optical waveguide configured for propagating an optical mode from the input end to the output end, and wherein a mode field diameter of the optical mode at the input end is substantially the same as the mode field diameter at the output end.

Abstract: Described is a general strategy of bend-compensated, single-mode LMA fibers extended into a regime with higher total index contrast and where a larger gradient is used to cancel the perturbation of a tighter anticipated bend.

Abstract: An optical fiber includes a core region having a longitudinal axis. A cladding region surrounds the core region. The core region and cladding region are configured to support and guide the propagation of signal light in a fundamental transverse mode in the core region in the directions of the axis. The fiber has a bend-induced gradient of its equivalent index of refraction indicative of a loss in guidance of the mode. At least a portion of cladding region has a graded index of refraction opposite the bend-induced gradient. The cladding region is configured to have a substantially flat equivalent index in response to a bend of the optical fiber.

Abstract: The cladding absorption of a single-mode, gain-producing fibers is increased in fiber designs that includes a trench region disposed between the core and inner cladding regions. Increased cladding absorption is achieved while maintaining single-mode operation.

Abstract: A rare earth doped optical fiber amplifier is configured to have an enlarged core region and a trench formed adjacent to the core, where at least an inner portion of the trench is also formed to include a rare earth dopant. The presence of the rare earth dopant in the inner region of the cladding minimizes transient power fluctuations within the amplifier as the number of optical signals being amplified changes. The addition of rare earth dopant to the cladding increases the overlap between the pump, signal and the rare earth ions and thus improves the gain efficiency for the optical signal. The relatively large core diameter increases the saturation power level of the rare earth dopant and decreases the transients present in the gain as the input signal power fluctuates.

Abstract: A low-power “all-in-one” Yb/Raman optical fiber laser system includes a pump input, and a Yb/Raman resonator including a segment of integrated Yb/Raman fiber configured to provide both a ionic gain and Raman gain. A set of input gratings and output gratings define a series of reflector pairs that, together with the integrated Yb/Raman fiber, create a nested series of cavities that provide a stepwise transition from the input wavelength to a selected target output wavelength.

Abstract: An optical fiber coupler connects transmission multicore optical fiber (TMCF) with an amplifier multicore optical fiber (AMCF) and a plurality of optical pump fibers. The coupler includes a plurality of signal cores extending between a multicore input endface and a coupler output endface, and a plurality of pump cores extending between a pump input and the coupler output endface. The multicore input endface is connectable to the TMCF, and the pump input is connectable to the optical pump fibers. Each pump core is paired with a corresponding signal core to form a core pair that is adiabatically tapered such that signal light carried by the signal core is combined with pump light carried by the pump core. The coupler output endface is connectable to the AMCF such that the combined light output of each core pair is provided as an input to a respective AMCF core.

Abstract: An optical fiber includes a core region having a longitudinal axis. A cladding region surrounds the core region. The core region and cladding region are configured to support and guide the propagation of signal light in a fundamental transverse mode in the core region in the directions of the axis. The fiber has a bend-induced gradient of its equivalent index of refraction indicative of a loss in guidance of the mode. At least a portion of cladding region has a graded index of refraction opposite the bend-induced gradient. The cladding region is configured to have a substantially flat equivalent index in response to a bend of the optical fiber.

Abstract: The cladding absorption of single-mode, double-clad, gain-producing fibers is increased in fiber designs that includes a trench region disposed between the core and inner cladding regions. Increased cladding absorption is achieved while maintaining single-mode operation.

Abstract: A multicore fiber comprises a plurality of cores extending along the length of a fiber body. Each of the cores is surrounded by a cladding. The plurality of cores and surrounding cladding provide respective index variations, so as to form a respective plurality of waveguides for conducting parallel data transmissions from a first end of the fiber to a second end. The plurality of cores has a cross-sectional geometry in which the plurality of cores is configured in a polygonal array, in which at least some of the cores are positioned at the vertices of the array. The polygonal array is configured such that neighboring cores in the array are separated from each other by a distance that is sufficient to prevent crosstalk therebetween.

Abstract: An optical data link includes first and second pluralities of transmission devices, at least one of which is configured as an array. A multichannel transmission link has a first end connected to the first plurality of transmission devices and a second end connected to the second plurality of transmission devices so as to form a plurality of parallel transmission channels therebetween. The multichannel transmission link includes a multicore fiber with a plurality of individual cores having a configuration matching the array configuration of the at least one plurality of transmission devices. The multicore fiber has an endface connected directly to the at least one plurality of transmission devices, with the individual cores of the multicore fiber aligned with respective devices in the at least one plurality of transmission devices. Further described are access networks and core networks incorporating a transmission link comprising at least one span of a multicore fiber.

Abstract: Apparatus and method of simultaneously measuring a parameter of a plurality of cores in at least one optical fiber. An input tester at a first end of the test fiber has a plurality of tester signal inputs with a geometry substantially matching at least a portion of the core geometry of the fiber. At least one test input signal source coupled to the plurality of tester signal inputs. A signal measuring device is alignable at a second end of the fiber to measure the output of the test input signal. The input tester may include a tapered multicore coupler or a laser having a shield with apertures disposable between the laser and the fiber. In the latter case, a lens may be disposed between the shield and the fiber to project light from the laser that passes through the apertures onto the end of the fiber.

Abstract: An optical pedestal fiber is configured to be taperable to form a tapered fiber having a mode field diameter at the tapered end that differs from the mode field diameter at the untapered end in correspondence with the difference between the cladding diameter at the tapered end and the cladding diameter at the untapered end. A plurality of such pedestal fibers can be used to construct a tapered fiber bundle coupler that provides matching of both core pitch and mode field diameter between a plurality of input fibers and individual cores of a multicore fiber. Further, the tapered fiber bundle coupler can be constructed using a plurality of fibers, in which individual fibers are configured to have different effective refractive indices, thereby suppressing crosstalk therebetween.

Abstract: An optical transmission and amplification system includes a multichannel transmission span with a length of a multicore transmission fiber having a plurality of individual transmission cores. A first tapered multicore coupler provides connectivity between the plurality of transmission cores of the multicore fiber and a respective plurality of individual transmission leads. A fiber amplifier is provided having a plurality of individual cores including at least one pump core and a plurality of amplifier core. A second tapered multicore coupler provides connectivity between the amplifier cores of the fiber amplifier and a respective plurality of amplifier leads, and between the at least one pump core and a respective pump lead.