An optical transmission module includes: a main substrate having a front surface and a back surface; an optical connector having a connector substrate; a first transparent substrate disposed between the connector substrate and the main substrate; a heat source element disposed between the connector substrate and the back surface of the main substrate, and electrically connected to the main substrate; one or a plurality of wirings electrically connecting the heat source element to the main substrate, and each configured to transfer heat generated from the heat source element and the first transparent substrate, to the main substrate; a first special region preventing the heat generated from the heat source element and the first transparent substrate, from being transferred to the connector substrate; and a second special region providing a function of transferring the heat generated from the heat source element and the first transparent substrate.

A fiber laser apparatus includes: a short-length type fiber to which an active element is added and that has a length of 300 mm or less: a ferrule attached to an end of the fiber; and a housing that accommodates the fiber and supports the fiber with the ferrule. Each of the housing and the ferrule is composed of a material having a first thermal expansion coefficient that is equal to or have a predetermined difference from a second thermal expansion coefficient of a raw material of the fiber. The predetermined difference between the first and second thermal expansion coefficients is within −8.6×10.sup.−6 to 11.4×10.sup.−6/K.

An optical transceiver includes a housing, a heat dissipation module and an optical communication module. The heat dissipation module includes a first heat conductive component and a second heat conductive component accommodated in the housing. The first heat conductive component and the second heat conductive component are two independent components, and the first heat conductive component thermally contacts the second heat conductive component. The optical communication module is accommodated in the housing and thermally contacts the heat dissipation module.

A high performance connector that provides heat dissipation sufficient to support operation of high power consuming QSFP-DD transceivers. The connector may be housed in a cage with a first channel to receive a transceiver. A connector port may be aligned with the first channel, and a heat transfer element comprising a compressible portion may make mechanical and thermal contact with a transceiver inside the first channel. The compressible portion may be urged to contact a transceiver by a biasing element. The heat transfer element may be thermally coupled to a heat dissipating element outside the cage. The cage may have multiple channels, and the heat transfer element may be installed in a channel between other channels, each receiving transceivers such that the heat transfer element may receive heat from multiple transceivers.

An optical transceiver includes a housing, a heat dissipation module and an optical communication module. The heat dissipation module includes a first heat conductive component and a second heat conductive component accommodated in the housing. The first heat conductive component and the second heat conductive component are two independent components, and the first heat conductive component thermally contacts the second heat conductive component. The optical communication module is accommodated in the housing and thermally contacts the heat dissipation module.

A variety of methods and arrangements for latching a transceiver to a host printed circuit board (PCB) are described. The transceiver is secured to its electrical sockets by a latch that does not extend or only minimally extends beyond the transceiver footprint and height. In some embodiments the latch includes a thermal bridge that provides a heat transfer path between the transceiver and host substrate.

An optical subassembly includes a planar dielectric waveguide structure that is deposited at temperatures below 400 C. The waveguide provides low film stress and low optical signal loss. Optical and electrical devices mounted onto the subassembly are aligned to planar optical waveguides using alignment marks and stops. Optical signals are delivered to the submount assembly via optical fibers. The dielectric stack structure used to fabricate the waveguide provides cavity walls that produce a cavity, within which optical, optoelectronic, and electronic devices can be mounted. The dielectric stack is deposited on an interconnect layer on a substrate, and the intermetal dielectric can contain thermally conductive dielectric layers to provide pathways for heat dissipation from heat generating optoelectronic devices such as lasers.

An object is to provide an optical transceiver in which optical components can be mounted at a high density and heat generated by a heat generating component can be efficiently dissipated. An optical transceiver (11) according to the present invention includes housings (4a) and (4b), a positioning member (8a) configured to position an optical component (7a) inside the housings (4a) and (4b), and a substrate (5) with a heat generating component (6a) mounted thereon, the substrate (5) being housed in the housings (4a) and (4b), in which the positioning member (8a) is configured to determine a position of the optical component (7a) inside the housings (4a) and (4b) and to thermally connect the substrate (5) to the housings (4a) and (4b).

A connector has a case, a circuit board, and a thermal diffusing unit. The case has an inner surface. The circuit board is mounted in the case and has a heating source. The thermal diffusing unit abuts the inner surface of the case and the heating source of the circuit board. An area of the thermal diffusing unit abutting the inner surface is bigger than an area of the thermal diffusing unit abutting the heating source. A heat transfer coefficient of the thermal diffusing unit is bigger than a heat transfer coefficient of the case. With the structure above, the thermal diffusing unit is allowed to transmit heat from a small area to a big area, thereby improving the heat dissipation efficiency of the connector.

An optical transceiver includes a housing and an optical receptacle; optical subassemblies each having a sleeve and being configured to perform a photoelectric conversion, the sleeve facing to the optical receptacle; inner fibers each connected to the sleeve one to one; and a tray having a holding part and a guiding part, the holding part holding the optical subassemblies in line, the guiding part being formed on both outer sides of the holding part and a folding back area on an opposite side of the optical receptacle. The guiding part includes a pair of passage parts. The inner fiber passes through one of the passage parts, the folding back area, and another of the passage parts in this order within the tray so as to face the optical receptacle again when the another of the passage parts is closer to the sleeve than the one of the passage parts.