A light source unit generates an optical signal out of a bend-insensitive (“BI”) optical fiber that is compliant with a desired encircled flux (“EF”). The unit includes a light source to generate an optical light signal and a conventional multimode optical fiber coupled to receive the optical light signal from the light source at a first end. A modal conditioner is arranged to condition the optical light signal propagating along different modes of the conventional multimode fiber. A first bend-insensitive (BI) multimode optical fiber has an input end, the input end of the first BI multimode optical fiber being coupled at a second end of the conventional multimode optical fiber to receive the conditioned optical light signal from the conventional multimode fiber. The output from the first BI multimode optical fiber outputs an optical signal having the desired EF.

Apparatus for laser processing a material (11), which apparatus comprises a laser (1), an optical fibre (2), and a coupler (125), wherein: the laser (1) is connected to the optical fibre (2); the optical fibre (2) is such that laser radiation (13) is able to propagate along the optical fibre (2) in a first optical mode (21) having a first mode order (24), a second optical mode (22) having a second mode order (25), and a third optical mode (23) having a third mode order (26); the third mode order (26) is higher than the second mode order (25); and the second mode order (25) is higher than the first mode order (24); the apparatus being characterized in that: the coupler (125) is configured to switch laser radiation propagating in the first optical mode (21) to the laser radiation propagating in the second order mode (22); and the coupler (125) is configured to switch the laser radiation propagating in the second optical mode (22) to laser radiation propagating in the third order mode (23).

Embodiments are disclosed for a coupling element with embedded modal filtering for a laser and/or a photodiode. An example system includes a laser and an optical coupling element. The laser is configured to emit an optical signal. The optical coupling element is configured to receive the optical signal emitted by the laser. The optical coupling element is also configured to be connected to an optical fiber such that, in operation, the optical signal is transmitted from the laser to the optical fiber via the optical coupling element. Furthermore, the coupling element comprises a tapered section that provides modal filtering of the optical signal.

A photonic integrated circuit (PIC) includes photonic components fabricated on the PIC. One of the photonic components includes an optical coupler configured to optically couple to an optical component. The optical coupler includes waveguide elements arranged in a 2-Dimensional array that is configured to provide a first mode having a first shape chosen to match a second shape of a second mode of the optical component.

To relax the accuracy with respect to a positional deviation, and thus to reduce costs. An optical waveguide is included that performs propagation only in a reference mode at a first wavelength. Communication is performed using light that has a second wavelength and includes a component of at least a first order mode in addition to a component of the reference mode. Here, the second wavelength is a wavelength that enables the optical waveguide to perform propagation in at least the first order mode in addition to the reference mode. For example, a light path adjuster that adjusts a light path such that input light is guided to a core of the optical waveguide, is further included.

Disclosed are techniques for generating a laser output beam having a functionally homogenized intensity distribution. According to some embodiments, a population of few modes in a multi-mode confinement core is excited by application of a low-moded source beam to the multi-mode confinement core, such that the population exhibit an unstable intensity distribution. The unstable intensity distribution is functionally homogenized by providing one or both of modulation of phase displacement in the multi-mode confinement core and variation of launch conditions of the low-moded source beam into the multi-mode confinement core.

A method for mitigating modal noise includes applying a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment. A modal-noise mitigator for a multimode optical fiber includes an actuator configured to apply a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment.

A patch cord for transmitting between a single mode fiber (SMF) and a multi-mode fiber (MMFs) has a MMF, SMF, and a photonic crystal fiber (PCF) with a hollow core placed between the SMF and MMF. A mode field diameter (MFD) of the PCF hollow core section is in the range of 16 to 19 microns, the length of the PCF is between 1 cm to 10 cm, the MMF has 50+2 microns core diameter, the SMF has a 6-9 microns core diameter, and the coupling between the PCF mode to the MMF fundamental mode is maximized.

Some embodiments of the disclosure relate to an optical transmission system that operates at a wavelength in the range from 950 nm to 1600 nm and that employs a single-mode optical transmitter and an optical receiver optically coupled to respective ends of a multimode fiber designed for 850 nm multimode operation. The optical transmission system also employs at least one single mode fiber situated within the optical pathway between the optical transmitter and the receiver and coupled to the multimode fiber.

A light source unit generates an optical signal out of a bend-insensitive (“BI”) optical fiber that is compliant with a desired encircled flux (“EF”). The unit includes a light source to generate an optical light signal and a conventional multimode optical fiber coupled to receive the optical light signal from the light source at a first end. A modal conditioner is arranged to condition the optical light signal propagating along different modes of the conventional multimode fiber. A first bend-insensitive (BI) multimode optical fiber has an input end, the input end of the first BI multimode optical fiber being coupled at a second end of the conventional multimode optical fiber to receive the conditioned optical light signal from the conventional multimode fiber. The output from the first BI multimode optical fiber outputs an optical signal having the desired EF.