A light detection device includes: a first optical fiber including a first core surrounded by a first cladding; a second optical fiber including a second core surrounded by a second cladding; a first cladding mode stripper provided outside the first cladding; a first light detector; and a second light detector. The second core has a diameter larger than a diameter of the first core and is connected to the first core. In a longitudinal direction of the first optical fiber, the first light detector is disposed on one side of the first cladding mode stripper and the second light detector is disposed on another side of the first cladding mode stripper.

An optical communication system includes a first communication system to communicate first information from a controller to a truck and a second communication system to communicate second information. The first communication system includes a first light emitter to output the first information, a first optical fiber to transport the light output from the first light emitter while letting the light leak therefrom, and a first light receiver to receive the light leaking from the first optical fiber. The second communication system includes a second light emitter to output second information, a second optical fiber to transport the light output from the second light emitter and input to the second optical fiber at some point along the second optical fiber, and a second light receiver to receive the light transported over the second optical fiber.

A mounting surface defines a branching channel, the branching channel having a main channel and one or more sub-channels branching off the main channel. An optic fiber is affixed to the mounting surface, the optic fiber including a cladding layer and an interior surrounded by the cladding layer, wherein part of the optic fiber is suspended over the main channel. A clad light stripper includes one or more discontinuities in an outer surface of the cladding layer of a suspended section of the optic fiber, the one or more outer surface discontinuities to release a portion of the process light. The one or more subchannels include a first sub-channel having an ingress located to capture released light from an individual one of the one or more discontinuities and trap at least a portion thereof.

A photodetection device including: first optical fibers; a second optical fiber; an optical combiner having: an end face connected to an end face of each of the first optical fibers; and another end face connected to an end face of the second optical fiber; a first photodetector that detects an intensity of light propagating through at least one of the first optical fibers; a second photodetector that detects Rayleigh scattering of light propagating through the second optical fiber; and a calculator that calculates the intensity of light propagating in a predetermined direction through the first optical fibers or the second optical fiber, from a result of detection by the first photodetector and a result of detection by the second photodetector.

A light transmission/reception probe system includes: a light source; a light transmission/reception probe including a first end portion in an axial direction, a second end portion on an opposite side of the first end portion, a core, a first cladding enclosing the core, and a leak enabling section configured to enable leakage of first light from an outer periphery of the first cladding toward an outside in a radial direction, the first light being output from the light source, coupled with the first cladding in the first end portion, and transmitted through the first cladding; a light receiving unit configured to receive second light arriving from an outside, coupled with the core in the second end portion, transmitted through the core, and output from the core in the first end portion; and a detecting unit configured to detect the second light received by the light receiving unit.

A leaky waveguide includes a waveguide configured to propagate light; a defect structure provided on a portion of the waveguide and configured to cause the light propagating in the waveguide to leak outside of the waveguide; and a plurality of detectors provided at predetermined positions adjacent to the defect structure and configured to detect the light leaking from the defect structure. Accordingly, a spectroscope including the leaky waveguide may have a reduced size.

A light detection device includes: a first optical fiber including a first core surrounded by a first cladding; a second optical fiber including a second core surrounded by a second cladding; a first cladding mode stripper provided outside the first cladding; a first light detector; and a second light detector. The second core has a diameter larger than a diameter of the first core and is connected to the first core. In a longitudinal direction of the first optical fiber, the first light detector is disposed on one side of the first cladding mode stripper and the second light detector is disposed on another side of the first cladding mode stripper.

An optical communication system includes a first communication system to communicate first information from a controller to a truck and a second communication system to communicate second information. The first communication system includes; a first light emitter to output the first information, a first optical fiber to transport the light output from the first light emitter while letting the light leak therefrom, and a first light receiver to receive the light leaking from the first optical fiber. The second communication system includes a second light emitter to output second information, a second optical fiber to transport the light output from the second light emitter and input to the second optical fiber at some point along the second optical fiber, and a second light receiver to receive the light transported over the second optical fiber.

Wavelength division multiplexing devices, and methods of forming the same, include a coupling lens and a waveguide, the lens being positioned over a mirror formed in a transmission path of the waveguide. The mirror reflects incoming light signals out of the transmission path through the lens and further reflects light signals coming from the lens and into the transmission path. An optical chip is positioned near a focal length of the lens. The optical chip has an optical filter configured to transmit a light signal at a first wavelength and to reflect received light signals at wavelengths other than the first wavelength.

Aspects of the present disclosure relate to detecting an optical signal and/or optical power in a ferrule-less optical fiber. In certain embodiments, one or more optical detectors are incorporated into an adapter that is configured to interface with a connectorized or non-connectorized ferrule-less optical fiber. The optical detector detects the presence or absence, and/or the optical power level, of the optical signal being transmitted through ferrule-less optical fiber and produces an electrical output representative of the detected optical signal.