Abstract: An optical fiber includes: a first core portion capable of transmitting first light; a second core portion formed on an outer periphery of the first core portion in a structure different from that of the first core portion and capable of transmitting second light different from the first light. The second core portion is formed around the outer periphery of the first core portion, and a center of the second core portion is positioned in a region of the first core portion.

Abstract: A fiber optical transceiver includes a package, a plurality of lead frames provided with the package and protruding outward from the package, a first circuit board installed in the package and electrically connected to the plurality of lead frames, and an optical element provided on the first circuit board. The package includes a ceramic portion formed of ceramic and covered with a metallized film.

Abstract: An optical fiber includes: a first core portion capable of transmitting first light; a second core portion formed on an outer periphery of the first core portion in a structure different from that of the first core portion and capable of transmitting second light different from the first light. The second core portion is formed around the outer periphery of the first core portion, and a center of the second core portion is positioned in a region of the first core portion.

Abstract: A fiber optical transceiver includes a package, a plurality of lead frames provided with the package and protruding outward from the package, a first circuit board installed in the package and electrically connected to the plurality of lead frames, and an optical element provided on the first circuit board. The package includes a ceramic portion formed of ceramic and covered with a metallized film.

Abstract: In an optical connector fitting structure, a first optical connector includes a first fixing member which fixes a first optical fiber to a first housing by being attached to the first housing while its locking state is changed from a temporarily locked state to an actually locked state, and a second optical connector includes a second fixing member which fixes a second optical fiber to the second housing by being attached to the second housing while its locking state is changed from a temporarily locked state to an actually locked state.

Abstract: In an optical connector fitting structure, a first optical connector includes a first fixing member which fixes a first optical fiber to a first housing by being attached to the first housing while its locking state is changed from a temporarily locked state to an actually locked state, and a second optical connector includes a second fixing member which fixes a second optical fiber to the second housing by being attached to the second housing while its locking state is changed from a temporarily locked state to an actually locked state.

Abstract: A signal transmission device drives a light-emitting element and outputs an optical signal depending on a data signal from an electronic device. The device includes an element driving portion which supplies a driving current to the light-emitting element, wherein the driving current is obtained by superimposing a modulation current on a bias current, the modulation current being dependent on the data signal indicating emitting information of the light-emitting element. A temperature compensation portion of the device controls the bias current and the modulation current depending on the temperature so that a temperature-current characteristic of the light-emitting element is reproduced based on the voltage which is dependent on the temperature and the voltage which is independent from the temperature, thereby performing current control depending on the temperature.

Abstract: Proposed is a technique for detecting a damaged VCSEL in a short time and at low cost. It shows the light emission spectrum of a multi-mode VCSEL before an ESD damage, and the light emission spectrum which shows several peaks corresponding to the structure of the active layer (MQW) and the upper and lower reflectors (DBR) is obtained. On the other hand, when the VCSEL which has an ESD damage has a damage in the active layer, the light emission spectrum which shows fewer peaks than the original number of peaks is obtained. Accordingly, the light spectrum analyzer analyzes the light emission spectrum, and it is determined that ESD damage has occurred when the number of peaks is equal to or smaller than a predetermined number, e.g., two peaks.

Abstract: Proposed is a technique for detecting a damaged VCSEL in a short time and at low cost. It shows the light emission spectrum of a multi-mode VCSEL before an ESD damage, and the light emission spectrum which shows several peaks corresponding to the structure of the active layer (MQW) and the upper and lower reflectors (DBR) is obtained. On the other hand, when the VCSEL which has an ESD damage has a damage in the active layer, the light emission spectrum which shows fewer peaks than the original number of peaks is obtained. Accordingly, the light spectrum analyzer analyzes the light emission spectrum, and it is determined that ESD damage has occurred when the number of peaks is equal to or smaller than a predetermined number, e.g., two peaks.