A system includes an optical transceiver configured to transmit and receive optical signals. The optical transceiver includes a Faraday rotator and a waveplate. The Faraday rotator and the waveplate are collectively configured to provide a relative polarization change between (i) light propagating in a first direction through the Faraday rotator and the waveplate and (ii) light propagating in a second direction opposite the first direction through the Faraday rotator and the waveplate. The waveplate may include a quarter waveplate or a half waveplate.

Disclosed is an optical sensor device for detecting a chemical analyte including a light source configured to generate probe light having a first wavelength spectrum, an optical fiber sensor probe including a mechanically processed optical fiber segment which is chemically functionalized to include a sensing material formed on exterior of the fiber segment, the optical fiber sensor probe coupled to receive and guide the generated probe light inside the optical fiber sensor probe while allowing optical evanescent coupling between probe light guided inside the optical fiber sensor probe and the sensing material, and a detector coupled to the optical fiber sensor probe to optically detect the guided probe light to obtain information on a material property of the sensing material.

A power over fiber system includes an optical fiber cable. The optical fiber cable includes a core, a first cladding and a second cladding. The core transmits signal light. The first cladding is positioned in contact with periphery of the core and transmits feed light. The second cladding is positioned in contact with periphery of the first cladding. Radial refractive index distribution of the first cladding is distribution in which refractive index gradually decreases from a local maximum at an internal point toward points where the first cladding is in contact with the core and the second cladding, respectively. The internal point is away from the core and the second cladding. The refractive index of the core is higher than the refractive index of the first cladding at the point where the first cladding is in contact with the core.

A monostatic, beaconless fiber transceiver for free-space optical links infers fine tracking information using receiver optoelectronics and an injected pointing dither (nutation). A MEMS steering mirror fine-points the beams and injects the nutation. While this may disturb fiber coupling and transmit beam pointing, link loss becomes negligible for sufficient SNR. The SNR for links without point-ahead correction is about 35 dB to keep dither loss below 0.1 dB and RMS spatial tracking noise below a tenth of the beam divergence. Since the pointing and tracking bandwidth is much smaller than the receiver communication bandwidth, this SNR is achievable with appropriate filtering. For point-ahead correction, a single-mode fiber transceiver can reach up to about 1 beamwidth of correction, while a few-mode fiber transceiver can reach up to about 1.75 beamwidths due to improved coupling sensitivity at higher point-ahead offsets. Using a double-clad fiber with a secondary detector further reduces the incurred coupling loss.

T/C, which is a ratio of an area T of a skirt part outside the boundary to an area C of the core region in a refractive index distribution, is 4% or more and 30% or less, the boundary is defined at a position where an absolute value of a change amount of the index becomes maximum between the center of the core region and the outer peripheral part of the first clad region, the area C of the core region is defined in a range from the center of the core region to the boundary in the radial direction, the area T of the skirt part is defined in a range from the boundary to the outer peripheral part of the first clad region.

A plastic scintillating fiber includes: an outermost peripheral layer containing a compound of a heavy metal element and containing a resin having scintillating properties; a core disposed inside the outermost peripheral layer and containing at least one type of fluorescent substance that absorbs the scintillation light generated from the outermost peripheral layer and wavelength-converts the absorbed light into light having a wavelength longer than that of the absorbed light; and a cladding layer covering an outer peripheral surface of the core and having a refractive index lower than that of the core. A wavelength shifting fiber including the core and the cladding layer, and the outermost peripheral layer covering an outer peripheral surface of the wavelength shifting fiber are integrally formed.

A monostatic, beaconless fiber transceiver for free-space optical links infers fine tracking information using receiver optoelectronics and an injected pointing dither (nutation). A MEMS steering mirror fine-points the beams and injects the nutation. While this may disturb fiber coupling and transmit beam pointing, link loss becomes negligible for sufficient SNR. The SNR for links without point-ahead correction is about 35 dB to keep dither loss below 0.1 dB and RMS spatial tracking noise below a tenth of the beam divergence. Since the pointing and tracking bandwidth is much smaller than the receiver communication bandwidth, this SNR is achievable with appropriate filtering. For point-ahead correction, a single-mode fiber transceiver can reach up to about 1 beamwidth of correction, while a few-mode fiber transceiver can reach up to about 1.75 beamwidths due to improved coupling sensitivity at higher point-ahead offsets. Using a double-clad fiber with a secondary detector further reduces the incurred coupling loss.

There is provided a multi-clad fiber assembly for reducing and eliminating deleterious laser-contaminant interrelations, and methods of making these assemblies. There is provided an optical connector having contaminants that are shielded from causing detrimental thermal effects, during laser beam transmittion, by preventing laser-contaminant interactions.

A fiber coupling device (100) includes the following components: a wedge plate (102) for receiving light and refracting the light in a predetermined direction, a condenser lens (104) for collecting the light refracted by the wedge plate (102); and an optical fiber (107) having an incident surface for receiving the light collected by the condenser lens (104). The wedge plate (102) is held rotatable around the optical axis (200) of the light incident on the wedge plate (102). The light refracted by the wedge plate (102) and collected by the condenser lens (104) is incident on a different point on the incident surface depending on the rotation angle of the wedge plate (102).

T/C, which is a ratio of an area T of a skirt part outside the boundary to an area C of the core region in a refractive index distribution, is 4% or more and 30% or less, the boundary is defined at a position where an absolute value of a change amount of the index becomes maximum between the center of the core region and the outer peripheral part of the first clad region, the area C of the core region is defined in a range from the center of the core region to the boundary in the radial direction, the area T of the skirt part is defined in a range from the boundary to the outer peripheral part of the first clad region.