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.

An optical connection device includes a light source section configured to emit light, a light guide section configured to guide the light emitted from the light source section and including an emitting section configured to emit the guided light to the outside, and a light receiving section configured to receive the light emitted from the emitting section. At least one of the light source section and the light receiving section turns around a turning axis. Therefore, a transmission distance of the light from the light source section to the light receiving section changes.

A mounting structure for a light guide having a core and a longitudinal axis, wherein the mounting structure includes a holder into which the light guide is insertable obliquely or perpendicular to the longitudinal axis, and the mounting structure is configured to provide an optical coupling to the core of the light guide.

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 monitoring mechanism for monitoring light in an optical circuit (10) including a loopback mirror (12) in loopback shape to which a linear optical waveguide (11) is connected has a structure in which a tap port (15) in loopback or loop shape is placed in close proximity to a position on the loopback mirror (12) where optical lengths from a connection point between the loopback mirror (12) and the optical waveguide (11) when light travels clockwise and when light travels counterclockwise are equal, which enables extraction a part of light from the loopback mirror (12) to the tap port (15) as monitoring light without optical loss. A light monitoring mechanism having a structure that minimizes the occurrence of optical loss when extracting light for monitoring is thereby provided.

A mounting structure for a light guide having a core and a longitudinal axis, wherein the mounting structure includes a holder into which the light guide is insertable obliquely or perpendicular to the longitudinal axis, and the mounting structure is configured to provide an optical coupling to the core of the light guide.

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.

An optical connection device includes a light source section configured to emit light, a light guide section configured to guide the light emitted from the light source section and including an emitting section configured to emit the guided light to the outside, and a light receiving section configured to receive the light emitted from the emitting section. At least one of the light source section and the light receiving section turns around a turning axis. Therefore, a transmission distance of the light from the light source section to the light receiving section changes.

The exemplary systems, apparatus, structures, and methods may include an assembly including substrate, an optical waveguide, and an optical access associated with the optical waveguide. Light from the optical access may be measured along the optical waveguide. The coupling loss of the optical waveguide may be determined based on at least the light measurements from the optical access.

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.