Abstract: A reflective type optical signal distributor comprising, in a housing (2), a plurality of optical input/output units (3) functioning as input and output terminals for an optical signal, an optical circuit assembly (6) for reflecting and separating the optical signal, and a plurality of guide optical fibers (8) for connecting the plurality of optical signals entering any one of the plurality of optical input/output units (3) and the optical circuit assembly (6), whereby an optical input/output units (3) is substantially equally distributed to all other ones of the plurality of optical input and output units (3), the optical circuit assembly (6) comprising an optical circuit in which a plurality of independent branched optical waveguides (22) merge into a single main optical waveguide (21), a reflective surface (4) formed at an end of the main waveguide (21), and the plurality of guide optical fibers (8) being connected to the corresponding plurality of independent branched optical waveguides (22).

Abstract: The present invention is an optical device including an optical circuit in which a plurality of branched optical waveguides are connected to a light receiving side and a light ejecting side of a main optical waveguide which mixes the entering light. The branched optical waveguides include a beginning and a terminal end. The terminal end is connected to an optical fiber and the beginning end is connected to the main optical waveguide. At least one of the branched optical waveguides has a slope or taper construction which is wider at the terminal end than at the beginning end, in order to improve lost variance and to reduce loss of light signals. The present invention also provides a method for manufacturing the above-described optical device to be used in optical local networks and optical instrumentation control systems.

Abstract: A reflection type magnetooptic sensor head. The respective structural elements are aligned in the order of a light source, light inputting/outputting path, polarizer, Faraday rotator, and reflecting film. The Faraday rotator is made of a (111) bismuth-substituted iron garnet single crystal film. The Faraday rotator is positioned such that the optical axis of the light incident upon the surface of the Faraday rotator makes an angle of 10 to 70 degrees with an axis normal to the surface of the Faraday rotator. The sensor head may further include two identical rectangular prisms positioned such that the Faraday rotator is sandwiched between the slanting surfaces of the prisms.

Abstract: A reflection type magnetooptic sensor head is disclosed. The respective structural elements are aligned following a light source in the order of a light inputting/outputting path, polarizer, Faraday rotator, and reflecting mirror. The Faraday rotator is made of a (111) bismuth-substituted iron garnet single crystal film having [111] axis at an angle of 5-60 degrees with an axis normal to the film surface. The reflecting mirror is positioned such that a light incident upon the reflecting mirror is substantially normal to the surface of the reflecting mirror.

Abstract: Optical device to optically connect an outside optical fiber with an optical waveguide through the connecting medium of an optical fiber with ferrule located within the hole of the optical receptacle that is fixed at the optical waveguide. The optical waveguide and the outside optical connectors are optically connected with high accuracy and small optical loss. Because no damage is caused to the optical waveguide by attachment or removal of the optical connectors, the optical performance of the optical device is not reduced.

Abstract: An optical isolator comprises two birefringent plates one of which separates two light components whose planes of polarization are perpendicular to each other to make the two light components spatially separate between the two birefringent plates and pass through two separate optical paths and the other of which thereafter combines the two separate light components, two Faraday rotators disposed between the two birefringent plates and having a Faraday rotation angle of approximately 45 degrees, a polarizer disposed between the two Faraday rotators and having a predetermined polarized-light transmitting angle, and a magnetic field device for applying an external magnetic field to the two separate optical paths in the two Faraday rotators to magnetize respective regions near the two optical paths in each of the rotators in opposite magnetization directions to each other.

Abstract: A multi-terminal star coupler having a circuit constituted by optical waveguides integrated on a substrate. For example, in a four-terminal star coupler, four uniformly three-dividing optical couplers are provided for branching from any one terminal to the other three terminals, and an optical waveguide from any one terminal to another terminal not adjacent to the one terminal includes an intersection portion where the optical waveguide intersects another optical waveguide lead from another terminal adjacent to the one terminal.

Abstract: A high quality small-sized polarization independent optical isolator for use in an optical fiber communication system, wherein a pair of magneto-optical elements having Faraday rotation angle of 45.+-.5 are contained in permanent magnets and arranged between a pair of birefringent crystal plates for splitting and combining an optical path of a laser light, and two polarizers arranged in parallel as being bounded on the midpoint of separated optical paths are interposed between the pair of magneto-optical elements, whereby a degree of worsening the optical isolation can be kept minimum against variations of an environmental temperature and wave length.

Abstract: A process for easily producing a silica glass plate having an internal refractive index distribution suitable for a planar optical waveguide involves carrying out the following steps.(a) A porous silica gel plate produced by a sol-gel method is kept in a reactor, the pressure of which is reduced to a substantially vacuum state.(b) Germanium tetrachloride gas is introduced into the reactor at a partial pressure appropriate to establish an absorption equilibrium between a desired concentration of germanium tetrachloride in said porous silica gel plate and a partial pressure of germanium tetrachloride introduced.(c) The partial pressure of germanium tetrachloride in step (b) is reduced so as to desorb germanium tetrachloride from the surface of the porous silica gel plate.(d) The porous silica gel plate having a described concentration distribution is brought into contact with water within or outside the reactor so as to fix the distribution.

Abstract: A chemically and physically stable humidity sensor including a porous sintered body and electrodes, which is formed by bringing a humidity sensor including a porous sintered body and electrodes into contact with a solution of a polyurethane resin.

Abstract: An optical divider for multimode optical fibers of graded-index (GI) type composed of an optical input section for securing input optical fiber, a branching section including an optical waveguide having rectangular sectional shapes irrespective of a kind of material or a method of fabricating the same and consists of a main optical waveguide and branch waveguide, and an optical output section for securing an array of output optical fibers, wherein the main optical waveguide having a width D and a length M is divided contiguously into N branch optical waveguides, preferably three or more having uniform width W, the optical waveguide having substantially uniform core thickness T is specifically related with the core diameter K of the otpical fiber to fufull the following relational formulas:0.7.ltoreq.T/K.ltoreq.0.85 (1)0.35.ltoreq.W/K.ltoreq.0.80 (2)15.ltoreq.M/D.ltoreq.70 (3)D=N.times.

Abstract: A main optical waveguide portion and/or branching optical waveguide portions of the optical waveguide is tapered in such a way so as to expand towards the output side for reducing a coupling loss due to mismatching of numerical apertures N.A. between optical fibers and the optical waveguide, wherein the light entering the optical waveguide at an angle determined by the numerical aperture N.A. of the optical fiber gradually reduces its angle of incidence to an interface of the core and cladding as it passes by a portion where the taper is provided and when the light reaches the output side of the optical fiber, the numerical aperture N.A. thereof is effectively reduced to a value which is lower than the numerical aperture N.A. determined by a difference of refractive-indices in the optical waveguide. By making the numerical aperture N.A.

Abstract: This invention provides a magneto-optic garnet grown by liquid phase epitaxy on a nonmagnetic garnet substrate and having a composition of the following formula (1)Ho.sub.x Tb.sub.y Bi.sub.3-x-y Fe.sub.5 O.sub.12 (1)wherein 0.3.ltoreq.y/x.ltoreq.1.0 and x+y<3.0.According to this invention there is provided a magneto-optic garnet as a Faraday rotator for use in an optical isolator, optical circulator, etc., utilizing Faraday effect, which has a very large Faraday rotation coefficient, a small difference in lattice constant from a nonmagnetic garnet substrate, exhibits a mirror face without causing a film defect (or so-called pit), and has a small temperature dependency.