A system for transmission of optical data signals has first optical processing circuitry for receiving a plurality of digital signals and applying at least one of a Hermite-Gaussian function, a Laguerre-Gaussian function or an Ince-Gaussian function to each of the received plurality of digital signals. The first optical processing circuitry also combines each of the at least one of the Hermite-Gaussian function, the Laguerre-Gaussian function or the Ince-Gaussian function applied plurality of digital signals into a single carrier signal. An optical transmitter transmits the single carrier signal. An optical receiver receives the transmitted single carrier signal. Second optical processing circuitry separates the at least one of the Hermite-Gaussian function, the Laguerre-Gaussian function or the Ince-Gaussian function applied digital signals of the single carries signal into separate signals and removes the at least one of the Hermite-Gaussian function, the Laguerre-Gaussian function or the Ince-Gaussian function applied to each of the plurality of digital signals. An elliptical core fiber transmits the single carrier signal from the optical transmitter to the optical receiver. The elliptical core fiber includes an elliptical core have a major axis and a minor axis.

Techniques are provided for radiation-induced birefringence in a Polarization-Maintaining Fiber (PMF). In one example, a fiber is obtained. At least one local volume of the fiber is irradiated to induce an end-to-end birefringence in the fiber. Based on the end-to-end birefringence induced in the fiber, a PMF is produced.

Techniques are provided for radiation-induced birefringence in a Polarization-Maintaining Fiber (PMF). In one example, a fiber is obtained. At least one local volume of the fiber is irradiated to induce an end-to-end birefringence in the fiber. Based on the end-to-end birefringence induced in the fiber, a PMF is produced.

An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

Provided is a polarization-combining module in which it is possible to suppress deviation of an optical axis in a polarization-combining optical system and to perform efficient polarization combination with a less optical loss.

A polarization-combining module includes: a PBS 4 which combines two linearly polarized lights input and emits the combined light; a λ/2 wavelength plate 3 which is provided on an optical path of at least one of the two linearly polarized lights which are input to the PBS 4, and provides polarization rotation by a predetermined angle to the linearly polarized light that passes therethrough; and a pedestal member 10 on which the λ/2 wavelength plate 3 and the PBS 4 are mounted, in which the pedestal member 10 has a protrusion part 12 which defines mounting positions of the λ/2 wavelength plate 3 and the PBS 4 so as to be separated from each other and be parallel to each other, and the λ/2 wavelength plate 3 and the PBS 4 are mounted on the pedestal member 10 with apart of each of the λ/2 wavelength plate 3 and the PBS 4 being brought into contact with the protrusion part 12.

The present disclosure provides a pitch reducing optical fiber array or a multicore fiber including at least one chiral fiber grating incorporated therein that is operable to couple the modes in different fiber cores within a spectral range determined in some instances by the helical pitch of the corresponding chiral fiber grating.

The present invention provides methods and systems for measuring optical power that require neither alterations to the optical fiber nor physical contact with the optical fiber, the system including an optical fiber configured to propagate an optical signal, wherein the optical fiber includes a core and at least a first cladding layer, wherein a portion of the optical signal scatters out of the optical fiber along a length of the optical fiber to form scattered fiber light; a detector system configured to receive the scattered fiber light along the length of the optical fiber and to output a detection signal based on the received scattered fiber light; and a processor configured to receive the detection signal and to determine a power value of the optical signal based on the received detection signal.

The present invention provides methods and systems for measuring optical power that require neither alterations to the optical fiber nor physical contact with the optical fiber, the system including an optical fiber configured to propagate an optical signal, wherein the optical fiber includes a core and at least a first cladding layer, wherein a portion of the optical signal scatters out of the optical fiber along a length of the optical fiber to form scattered fiber light; a detector system configured to receive the scattered fiber light along the length of the optical fiber and to output a detection signal based on the received scattered fiber light; and a processor configured to receive the detection signal and to determine a power value of the optical signal based on the received detection signal.

In this multi-core fiber, a plurality of cores are arranged at a prescribed interval, and the peripheries thereof are covered by a cladding having a lower refractive index than the plurality of cores. A resin coating is formed on the outer periphery of the cladding. A colored section is formed on a section of the outer surface of the resin coating in the peripheral direction. The colored section is formed continuously along the length direction of the multi-core fiber. In a multi-core fiber cross section orthogonal to the length direction, the position of a specific core and the peripheral position where the colored section is formed are substantially constant along the length direction of the multi-core fiber. In other words, in the multi-core fiber cross section orthogonal to the length direction, the position of the specific core and the position where the colored section is formed are substantially constant along the length direction of the multi-core fiber.