An optical fiber securing structure includes: an optical fiber including a coating, and a coating-removed section in which a partial section of the coating is removed from the optical fiber; a reinforcement member including main surfaces and a groove formed from one of the main surfaces toward an inside of the reinforcement member, where the groove has a pair of side walls and a bottom wall; and a resin member that secures the coating-removed section to the pair of side walls and the bottom wall. A bottom part of the groove that includes the bottom wall has a widthwise cross-sectional shape where the bottom wall constitutes a trapezoidal shape such that a distance between the pair of side walls becomes greater in a direction away from the bottom wall.

Provided is a light detecting device including a light input device configured to receive light, a plurality of waveguides extending from the light input device, the plurality of waveguides being configured to transmit portions of the light received by the light input device, respectively, a plurality of modulators provided on the plurality of waveguides and configured to modulate phases of the portions of light transmitted in the plurality of waveguides, respectively, at least one graphene layer configured to absorb the portions of light transmitted in the plurality of waveguides, and at least one first electrode and at least one second electrode electrically connected to the at least one graphene layer, respectively.

The present invention provides a filter composed of two layers of materials with different expansion coefficients. The difference between a length added to a whole section length of an outer low-expansion coefficient metal sleeve by a temperature change and a length added to a length of a whole section of high-expansion coefficient cylindrical coil spring arranged therein by the temperature change causes a stress-releasing or stress-increasing effect on the whole section of pre-tensioned high-expansion coefficient cylindrical coil spring arranged therein, so that a structure capable of compensating the wavelength shift of the fiber Bragg's grating filter caused by temperature by increasing or decreasing the refractive index is achieved.

An optical fiber securing structure includes: an optical fiber including a coating, and a coating-removed section in which a partial section of the coating is removed from the optical fiber; a reinforcement member including main surfaces and a groove formed from one of the main surfaces toward an inside of the reinforcement member, where the groove has a pair of side walls and a bottom wall; and a resin member that secures the coating-removed section to the pair of side walls and the bottom wall. A bottom part of the groove that includes the bottom wall has a widthwise cross-sectional shape where the bottom wall constitutes a trapezoidal shape such that a distance between the pair of side walls becomes greater in a direction away from the bottom wall.

A compact method for forming strong hermetic bonds and seals. Such bonds are made simply and with no intervening adhesives, by directly melting a thermoplastic polymer against or between two surfaces of thermoset materials.

A temperature correcting pressure gauge which has a diaphragm having at least one surface coupled to a source of pressure to be measured, the diaphragm first surface having a first FBG from a first optical fiber attached in an appropriately sensitive region of the diaphragm, a FBG from a second optical fiber attached to the opposite surface from the first FBG, the first and second FBGs reflecting or transmitting optical energy of decreasing or increasing wavelength, respectively, in response to an applied pressure. The first and second FBGs have nominal operating wavelength ranges that are adjacent to each other but are exclusive ranges and the FBGs also have closely matched pressure coefficients and temperature coefficients.

A temperature correcting pressure gauge which has a diaphragm having at least one surface coupled to a source of pressure to be measured, the diaphragm first surface having a first FBG from a first optical fiber attached in an appropriately sensitive region of the diaphragm, a FBG from a second optical fiber attached to the opposite surface from the first FBG, the first and second FBGs reflecting or transmitting optical energy of decreasing or increasing wavelength, respectively, in response to an applied pressure. The first and second FBGs have nominal operating wavelength ranges that are adjacent to each other but are exclusive ranges and the FBGs also have closely matched pressure coefficients and temperature coefficients.

An optical refrigeration system that includes a heatlink that is formed by textured crystals that are matched in coefficient of thermal expansion (CTE) to the yttrium lithium fluoride (YLF) cooling crystal, and shaped in geometries that result in very low heat producing losses (HPL). The optical refrigeration system may further include a mirror that is made of a semiconductor-material.

An embodiment of the indention includes a passive, fiber optic, thermal insulator. The thermal insulator includes an inner sleeve defining a central access port. The thermal insulator includes an outer sleeve concentric to the inner sleeve. The inner sleeve and the outer sleeve are joined sufficient to define an annular void. The thermal insulator includes a first insulator located in the annular void. Optionally, the apparatus includes at least one optical fiber secured in the central access port.

A temperature correcting pressure gauge which has a diaphragm having at least one surface coupled to a source of pressure to be measured, the diaphragm first surface having a first FBG from a first optical fiber attached in an appropriately sensitive region of the diaphragm, a FBG from a second optical fiber attached to the opposite surface from the first FBG, the first and second FBGs reflecting or transmitting optical energy of decreasing or increasing wavelength, respectively, in response to an applied pressure. The first and second FBGs have nominal operating wavelength ranges that are adjacent to each other but are exclusive ranges and the FBGs also have closely matched pressure coefficients and temperature coefficients.