The quantitative determination of various materials in highly scattering media such as living tissue may be determined in an external, photometric manner by the use of a plurality of light sources positioned at differing distances from a sensor. The light from said sources is amplitude modulated, and, in accordance with conventional frequency domain fluorometry or phosphorimetry techniques, the gain of the sensor is modulated at a frequency different from the frequency of the light modulation. Data may be acquired from each of the light sources at differing distances at a frequency which is the difference between the two frequencies described above. From these sets of data from each individual light source, curves may be constructed, and the slopes used to quantitatively determine the amount of certain materials present, for example glucose, oxyhemoglobin and deoxyhemoglobin in living tissue.

Photosensor with multiple light sources

Method and device for generating optical pulses. According to the invention, in order to generate an optical signal in the form of optical pulses, a semiconductor laser (2) is made to function as gain commutation, and a portion of the light produced by this laser is reinjected into the laser. The light to be reinjected is previously filtered by an optical filter (12) which is tuned to one of the modes of the laser. Another portion of the light produced by the laser is used as an optical signal after having been filtered this portion by the optical filter.

Method and device for generating optical pulses

There is provided a polarization maintaining optical fiber coupler and a method of manufacturing this polarization maintaining optical fiber coupler in which manufacturing is simplified and excess loss is reduced. A polarization maintaining optical fiber coupler is provided in which, in at least one of the polarization maintaining optical fibers forming the fused and extended portion, the ratio of the [diameter of the core/the diameter of the cladding] or [the distance between the two stress applying portions/the diameter of the cladding] is greater than the ration of the [diameter of the core/the diameter of the cladding] or [the distance between the two stress applying portions/the diameter of the cladding in the portions of the polarization maintaining optical fibers that do not form the fused and extended portion]. In addition, in this polarization maintaining optical fiber coupler, in the fused and extended portion, the stress applying portions are enveloped by the cladding. Moreover, polarization maintaining optical fibers are used in which the distance between adjacent outer circumferences of the two stress applying portions is 20 μm or more.

Polarization maintaining optical fiber coupler and method of manufacturing same

Optical detector and method for detection of a chemical compound

PROBLEM TO BE SOLVED: To provide a light system and a drink holder capable of easily recognizing a placing position of a beverage container even if it is dark in the vehicle.SOLUTION: The drink holder 20 is provided with a lighting system 10 and an outer case 22. The lighting system 10 is provided with a bottom face 11, side faces 12, and an irradiation side reflection means 13. Inner faces of the bottom face 11 and the side faces are formed of a member for reflecting light and irregularly reflecting light, and the irradiation side reflection means 13 is formed of a light transmission reflection member 13a, and the means at the position facing an intermediate member 10c is formed of a reflection member 13b of a light non-transmission property. A point light source is provided on the bottom face 11 of a position corresponding to the intermediate member 10c or on the inner face of the irradiation side reflection means 13. The outer case 10 has a recessed portion 21 formed deeper than the height of the side faces 12 of the lighting system 10, and the lighting system 10 is placed in the recessed portion 21 and a pushing member 23 is provided on the irradiation side reflection means 13 at a position corresponding to the intermediate member 10c of the lighting system 10.

Lighting system and drink holder using this

PURPOSE:To constitute the coupler so that polarization stability is high and =16dB even when a wavelength difference is small by providing two points or more of optical coupling parts in a twisted part of an optical fiber CONSTITUTION:Two pieces of single mode optical fiber f1, f2 constituted of cores 61, 62 and 81, 82, respectively are prepared As for the optical fibers f1, f2, the core diameter is 8-10mum, and the diameter is reduced until the clad outer diameter becomes 10-30mum, and subsequently, these reduced diameter parts are twisted together In this twisted part, plural pieces of, for instance, optical coupling parts 2, 4 are formed in two points Also, as for the optical coupling parts 2, 4, it is desirable to form them so that the array directions of the adjacent cores 61, 62 are different from each other about 90 deg along its longitudinal direction in the optical coupling part 2 and the optical coupling part 4, in the case its transverse section is looked at

Optical multiplexing/demultiplexing coupler and its manufacture

PURPOSE:To allow the effective use of panda type polarization maintaining optical fibers for optical measurement or as optical fiber sensors by fusing and stretching the fibers which are reduced in diameter down to a prescribed shape by an etching agent. CONSTITUTION:The panda type polarization maintaining optical fibers 1 are used and are immersed into a satd. soln. mixture composed of hydrofluoric acid and aq. ammonium fluoride soln. The panda type polarization maintaining optical fibers 1 are made into the elliptic optical fibers 1' having 60mum major diameter (a) and 40mum minor diameter(b). While the panda type polarization maintaining optical fibers 1', 1 reduced in the diameter in such a manner are heated together, the fibers are subjected to the fusing and stretching treatment under tension. The branching ratio does not largely vary in an X direction (X polarization) and Y direction (Y polarization) in such a case and, therefore, the arbitrary setting of the branching ratio is possible. Such fibers are effectively utilziable for optical measurement or as the optical fiber sensor.

Production of polarization maintaining optical fiber coupler

PURPOSE:To improve the stability over the entire part of a system by providing the optical fiber coupler with polarization characteristics and the branching ratios to light of >=2 specific wavelengths within a specific range, thereby making it possible to improve the polarization characteristics of a fiber amplifier, to narrow the range to be controlled of a phase compensator and to obtain a stable optical output. CONSTITUTION:The polarization maintaining optical fiber 1 is formed by fusing and stretching to have the polarization characteristics and to have >=98/2 or =2 specific wavelengths. The polarization maintaining optical fiber 1 has the anisotropy of a refractive index distribution in the specific direction of the plane of polarization. The light propagation constant of the fiber varies with the one direction of the plane of polarization to be preserved and the direction of the plane of polarization orthogonal therewith. Namely, the polarization maintaining optical fiber 1 has the characteristics varying in the branching ratio to the light having the same wavelengths and the different direction of the plane of polarization by a difference in the light propagation constant depending upon the direction of the plane of polarization of the optical fiber 1, i.e., the optical fiber has the polarization characteristics.

Optical fiber coupler for optimum multiplexing and demultiplexing and production of the same

PURPOSE:To provide an optical fiber coupler which can be easily connected to a general optical fiber and separate a light having a prescribed wavelength into X-polarized wave and Y-polarized wave whose planes of polarization mutually cross at right angles, or compose them, never require, therefore, a working such as the complicated optical axis regulation of an optical element such as a polarized wave separating prism or lens, and can be effectively utilized for optical communication system, and a method for manufacturing this optical fiber coupler CONSTITUTION:An optical fiber coupler 10 is formed by diameter-narrowing a panda type polarized wave holding optical fiber 1 into a prescribed form, fusing and drawing the diameter-narrowed parts with the polarization plane directions being arranged in parallel to each other This optical fiber coupler 10 can separate a light having a prescribed wavelength incident from one inlet port P1 into X-polarized wave and Y-polarized wave in outlet ports P3, P4, respectively, and also can enter the X-polarized wave and the Y-polarized wave from different inlet ports P3, P4 and transmit the light obtained by composing the X-polarized wave and the Y-polarized wave together from an outlet port Pi

Optical fiber coupler and its manufacture

PURPOSE:To provide the light wavelength filter which is easily manufacture and low in price and has high performance CONSTITUTION:One end part of an optical fiber (f) is curved to form a loop part fL, the jacket of the optical fiber at a parallel part fP where the optical fiber is arranged in a parallel state is removed, and this part is fused and drawn to form an optical coupling part The fusion and drawing process is so performed that the optical branching ratio to light of 130mum in wavelength (lambda1) is 0% and the optical branching ratio to light of 155mum in the other wavelength (lambda2) is 50%

Koshiba Yoshiaki

Papers

Optical multiplexing/demultiplexing coupler and its manufacture

Production of polarization maintaining optical fiber coupler

Optical fiber coupler for optimum multiplexing and demultiplexing and production of the same

Optical fiber coupler and its manufacture

Light wavelength filter