Abstract: An LED is mounted on a mounting portion of a lead frame with its light-emitting portion facing an aperture. Wires that connect the LED to lead portions of the lead frame are placed on the side on which the LED is mounted. A light-transmitting resin, which transmits light emitted from the LED, is placed on the side opposite from the LED mounted side of the lead frame. A low-stress resin, which seals the LED and the wire, is placed on the LED-mounted side of the lead frame. A crack prevention structure is constituted of bent portions that are provided at the lead portion and bent toward the LED-mounted side, low-stress resin portions located on the side opposite from the LED-mounted side with respect to the bent portions, and end portions of the light-transmitting resin put in contact with the low-stress resin portions.

Abstract: In a submount main body (1) composed of a single crystal silicon, a mounting surface (4) on which a light-emitting device (11) is mounted is composed of a (100)-oriented surface and the inner surface of a through hole (3) which is formed by anisotropic etching is parallel to the (110)-oriented surface. The light-emitting portion of the light-emitting device (11) is arranged to face a device-side opening (31) which opens into the mounting surface (4) of the submount main body (1). Consequently, heat generated in the light-emitting device (11) can be discharged to the outside more efficiently than the case where the light-emitting portion is arranged to face a side opposite to the submount side. Specifically, light from the light-emitting device (11) is reflected by a reflective surface formed on the surface of the through hole (3), and highly efficiently transmitted outside of the submount main body (1).

Abstract: An optical communication link has a plurality of light emitting elements and a plurality of light receiving elements associated with the respective light emitting elements, and a plurality of optical fibers each for conveying an optical signal emitted from one light emitting element to an associated light receiving element. The optical fibers have respective lengths that include at least two different lengths, and respective transmission losses per unit length that vary according the lengths of the optical fibers, so that variation of the transmission losses among the optical fibers due to difference in optical fiber length is prevented.

Abstract: A position of a first module (12a) with respect to an optical fiber (11) is determined in accordance with a receiving efficiency at the first module (12a) with respect to light emitted from the optical fiber (11). Power of light coupled into the optical fiber (11) from the first module (12a) is set in accordance with a value of a far-end reflectivity on a side of the first module (12a) in the position so as to satisfy a predetermined formula. By giving priority to determining a condition that significantly influences an improvement of an eye opening ratio, it is possible to manufacture an optical communication system at a low cost and with more freedom in manufacturing. Thus provided is a method of manufacturing an optical communication system, the method allowing for manufacturing an optical communication system at a low cost and with more freedom in manufacturing.

Abstract: In a bidirectional optical communications module capable of all-dual-mode communications using a single optical fiber, interference due to internally scattered light is reduced by forming a diverging area on a periphery of a transmission lens and providing a thin film reflection mirror which collects incoming light. A inexpensive, compact bidirectional optical communications module can be offered with reduced interference between outgoing and incoming light, especially, interference due to internally scattered light.

Abstract: In a submount main body (1) composed of a single crystal silicon, a mounting surface (4) on which a light-emitting device (11) is mounted is composed of a (100)-oriented surface and the inner surface of a through hole (3) which is formed by anisotropic etching is parallel to the (110)-oriented surface. The light-emitting portion of the light-emitting device (11) is arranged to face a device-side opening (31) which opens into the mounting surface (4) of the submount main body (1). Consequently, heat generated in the light-emitting device (11) can be discharged to the outside more efficiently than the case where the light-emitting portion is arranged to face a side opposite to the submount side. Specifically, light from the light-emitting device (11) is reflected by a reflective surface formed on the surface of the through hole (3), and highly efficiently transmitted outside of the submount main body (1).

Abstract: A sealing structure includes a lead frame having a light transmitting section, an optical element having an optical surface which is directed to the light transmitting section and is mounted on the lead frame in such a state that the optical element blocks the light transmitting section at its one end portion in an axis direction, and a sealing body that is formed in a region excluding an optical path and seals the optical element. By forming the sealing body in the region excluding the optical path, the light usage efficiency can be prevented from decreasing even when a material that can increase the environmental resistance is added to the sealing body. Further, since the optical element is mounted on the lead frame with its face down, the sealing structure can be easily formed even when the optical element is small-sized.

Abstract: An optical communication system has a plastic optical fiber (POF) and an optical communication module. The POF has a spherical end surface, and light emitted from the spherical end surface has an NA of 0.35 or lower. The POF is installed in the module such that a light receiving surface of a light receiving element (PD) is at a distance, d, from an apex of the spherical end surface. The distance, d, is within a range of 0<d?r*D/(n?n1) when a PD diameter is not larger than D, and within a range of D?d?r*D/(n?n1) when the PD diameter is larger than D, where D is a diameter of the POF, r*D is a radius of curvature of the spherical end surface, n is a refractive index of a core of the POF, and n1 is a refractive index of a substance between the spherical end surface and the PD.

Abstract: An LED is mounted on a mounting portion of a lead frame with its light-emitting portion facing an aperture. Wires that connect the LED to lead portions of the lead frame are placed on the side on which the LED is mounted. A light-transmitting resin, which transmits light emitted from the LED, is placed on the side opposite from the LED mounted side of the lead frame. A low-stress resin, which seals the LED and the wire, is placed on the LED-mounted side of the lead frame. A crack prevention structure is constituted of bent portions that are provided at the lead portion and bent toward the LED-mounted side, low-stress resin portions located on the side opposite from the LED-mounted side with respect to the bent portions, and end portions of the light-transmitting resin put in contact with the low-stress resin portions.

Abstract: At least one of end portions of a light-carrying core portion of a single-conductor optical fiber has an enlarged portion, which is a portion of the core portion larger than other portions of the core portion. An optical communications module includes a light emitting element which generates outgoing light, a sending lens which couples the outgoing light with an end portion of the single-conductor optical fiber, a light receiving element which receives incoming light from the single-conductor optical fiber, and a reflecting mirror which couples the incoming light with the light receiving element. The light emitting element and the sending lens are disposed so that the area in the end portion of the single-conductor optical fiber coupled with the outgoing light is at least partially included in the enlarged portion.

Abstract: Numerical aperture of transmitted light is varied to NAs by a transmitting lens. The numerical aperture, NAs, of the transmitted light is made larger than the numerical aperture, NAp, of an optical fiber, whereby the numerical aperture, NAf, of received light radiated from the optical fiber is made smaller as the transmission distance increases. A receiving optical system is arranged such that the receiving efficiency of the received light is increased by the provision of an aperture member according as the numerical aperture, NAf, is made smaller. This improves the receiving efficiency when the transmission distance is long and reduces a variation in the received light quantity even if the transmission distance is varied.

Abstract: An optical communication module including: an emission member for emitting a transmission light beam; and a connection member for detachably connecting an optical fiber for external communication with the emission member, the connection member including a tubular accommodation part for coaxially receiving and fixing an end of the optical fiber to be connected, wherein the emission member and the connection member are arranged such that the transmission light beam intersects with an optical axis of the optical fiber at a predetermined angle to enter an end face of the optical fiber when the optical fiber is connected and the transmission light beam collides with an inner wall of the accommodation part when the optical fiber is detached.

Abstract: An optical communication system has a plastic optical fiber (POF) and an optical communication module. The POF has a spherical end surface, and light emitted from the spherical end surface has an NA of 0.35 or lower. The POF is installed in the module such that a light receiving surface of a light receiving element (PD) is at a distance, d, from an apex of the spherical end surface. The distance, d, is within a range of 0<d?r*D/(n?n1) when a PD diameter is not larger than D, and within a range of D?d?r*D/(n?n1) when the PD diameter is larger than D, where D is a diameter of the POF, r*D is a radius of curvature of the spherical end surface, n is a refractive index of a core of the POF, and n1 is a refractive index of a substance between the spherical end surface and the PD.

Abstract: A bidirectional optical communication device satisfies a condition of ?fb?0??fa or ?fa?0??fb when ?fa and ?fb are angles of inclination between an optical axis of an optical fiber and transmission light after incidence with a numerical aperture NA at an outermost periphery, and ?fa and ?fb are expressed as the follows: ?fa=Sin?1[{n0 Sin(?L+Sin?1(NA)/n0+?T)}/nf]??T ?fb=Sin?1[{n0 Sin(?L?Sin?1(NA)/n0+?T)}/nf]??T where nf and no denote refractive indexes of a core of the optical fiber and air, respectively. The bidirectional optical communication device is capable of decreasing restraint of a transmission distance by reducing fluctuation of reception efficiency by the transmission distance and reducing interference between transmission light and reception light.

Abstract: An optical communication module in accordance with the present invention includes: an optical fiber; a light-receiving device for converting the beams of light emitted from the optical fiber to an electric signal; and a receiving optical section for coupling at least a part of the beams of light emitted from the optical fiber with the light-receiving device. The receiving optical section includes: a collecting optical system for directing at least a part of the beams of light emitted from the optical fiber to the light-receiving device; and an interference restraining section for restraining module-reflected beams of light reflected in a part of the optical communication module from being coupled with the optical fiber, the interference restraining section being provided in an area irradiated with at least a part of the module-reflected beams of light.

Abstract: A position of a first module (12a) with respect to an optical fiber (11) is determined in accordance with a receiving efficiency at the first module (12a) with respect to light emitted from the optical fiber (11). Power of light coupled into the optical fiber (11) from the first module (12a) is set in accordance with a value of a far-end reflectivity on a side of the first module (12a) in the position so as to satisfy a predetermined formula. By giving priority to determining a condition that significantly influences an improvement of an eye opening ratio, it is possible to manufacture an optical communication system at a low cost and with more freedom in manufacturing. Thus provided is a method of manufacturing an optical communication system, the method allowing for manufacturing an optical communication system at a low cost and with more freedom in manufacturing.

Abstract: In the organic waveguide of the present invention, on a buffer layer and a core section made of organic polymer which are formed on a substrate, there is provided a masking clad which serves as a mask when the organic polymer is processed by dry etching and which constitutes an upper clad, and an overclad made of inorganic dielectric such as silicon oxide is formed around the core section.

Abstract: A method for producing an optical device having a polyimide film through which a light beam is transmitted, which comprises applying a solution containing a polyamic film-forming starting material on a substrate and then baking the resultant under vacuum to form the polyimide film.

Abstract: A two-way optical communication device for use in a two-way optical communication system for transmitting and receiving an optical signal via a single optical fiber, comprises a light emitting element for generating transmitted light, a photodetector for receiving incoming light emitted from the optical fiber, and a reflection mirror made of a thin film having a high reflectance, having first and second surfaces, the first surface being opposite to the second surface. An optical member including the reflection mirror is provided closer to the optical fiber than the light emitting element. The incoming light emitted from the optical fiber is reflected by the first surface of the reflection mirror to be guided to the photodetector. The transmitted light emitted from the light emitting element or the transmitted light reflected by an end surface of the optical fiber is reflected by at least a portion of the second surface of the reflection mirror to prevent the transmitted light from entering the photodetector.

Abstract: At least one of end portions of a light-carrying core portion of a single-conductor optical fiber has an enlarged portion, which is a portion of the core portion larger than other portions of the core portion. An optical communications module includes a light emitting element which generates outgoing light, a sending lens which couples the outgoing light with an end portion of the single-conductor optical fiber, a light receiving element which receives incoming light from the single-conductor optical fiber, and a reflecting mirror which couples the incoming light with the light receiving element. The light emitting element and the sending lens are disposed so that the area in the end portion of the single-conductor optical fiber coupled with the outgoing light is at least partially included in the enlarged portion.