Abstract: The invention provides an optical communication apparatus and optical LAN system capable of either avoiding or reducing the adjustment difficulty during the busy traffic while suppressing the system enlargement. The optical LAN system 100 comprises optical communication apparatuses (hereinafter, referred to as “node.”) 1a˜1x, an optical multiplexing-branching means 2, and a plurality of pairs of optical fibers 3a˜3x. Each node 1a˜1x is capable of communicating with all of the other nodes 1b˜1x, 1a through first wavelength and also communicating among all nodes composing a certain group through one or more second wavelengths, blocking signal from its own. The optical multiplexing-branching means 2 multiplexes optical signals emanated from each node 1a˜1x and then branches it to all the nodes 1a1x. Each pair consists of a fiber 3at˜3xt for transmission and that for reception 3ar3xr; and the paired fibers communicatively connect each node with the optical multiplexing-branching means.

Abstract: The objective of the present invention is to provide with is to provide with a tunable laser module capable of adequately detecting the decay of the large variation in the wavelength of the light and then operating the shutter. The tunable laser module 1 comprises a tunable laser source 11˜13 capable of emitting light with a wavelength defined by wavelength control signal, and following controllers 14˜17, 18˜23, 24˜28. A temperature controller 14˜17 operates to perform the control of the temperature of the tunable laser source 11˜13. A wavelength controller 18˜23 operates to perform the control of the wavelength of the light emanating from the tunable laser source 11˜13. A power controller 24˜28 operates to perform the control of the power of the tunable laser source 11˜13.

Abstract: The objective of the present invention is to provide with control system and method for optical communication device application, the system and the method cooperatively controlling software and an optical device controller (hardware) contributing a plurality of loops, at least one of which having a singularity more than first order. In order to achieve the objective, the present invention provide with the following configuration. CPU performs the temperature control task as the highest priority task, and the others as lower priority tasks: such as the wavelength control task, the laser output level control task and other kind of tasks 4˜n. Service functions, which notify event, information, and so on to a client, are provided with as programs in order to message, for example the control task things, to the RTOS. There are three states as those of task, i.e.

Abstract: The objective of the present invention is to provide with a tunable laser light source and controlling method of the same capable of detecting the degree of out-of-tune-ness, maintaining simple configuration. The tunable laser light source comprises a gain medium 1, a tunable band rejector 2, an etalon 3, and a transmitted light detector 4. The gain medium 1 is capable of amplifying light within a wavelength band including a target wavelength. The a tunable band rejector 2 is positioned opposite the gain medium thereby forming an edge of a laser resonator and is capable of rejecting light with a certain wavelength tunable to the target wavelength from the incident light emanating from the gain medium while transmitting the remaining. The an etalon 3 is positioned between the gain medium and the tunable band rejector and is capable of selectively transmitting light with certain wavelengths including the target wavelength.

Abstract: The objective of the invention is to provide with a tunable LED module capable of easily selecting a wavelength and reducing particular parts, comparing to that of prior art. The tunable LED module according to the present invention is applicable to a certain short range communication.

Abstract: The invention is an optical switching device and optical receiver having a simpler configuration and capable of short range communication with a larger communication band than those of the prior art. The invention comprises a plurality of nodes and an optical switching device. Each node has an optical receiver and an optical transmitter. The optical switching device switches optical signals entering via incident ports from nodes, thereby sending them from sending ports. The device has an optical distributor and a functional optical combiner. The distributor distributes a common optical signal into all outgoing optical transmission lines. The combiner partially transmits each individual optical signal entering from a node to one or more outgoing optical transmission lines. The optical receiver has a beam splitter, a first optical detector, and a second optical detector. The beam splitter splits its incident optical signal into the individual optical signal and the common optical signal.

Abstract: The object of the present invention is to provide a semiconductor laser module capable of reducing the burdens for the arrangement of the optical system than the conventional one. The semiconductor laser module comprises: a semiconductor laser 1 for emitting, as a transmitted light, a light with a wavelength within a certain communication wavelength band such as, for example, 1.3 .mu.

Abstract: The object of the present invention is to provide a semiconductor laser module capable of reducing the burdens for the arrangement of the optical system than the conventional one. The semiconductor laser module comprises: a semiconductor laser 1 for emitting, as a transmitted light, a light with a wavelength within a certain communication wavelength band such as, for example, 1.3 .mu.

Abstract: To provide a wavelength-selection optical switch able to select a light with a certain wavelength and an optical add/drop multiplexer using the same. An optical switch comprising: a silicon substrate; a glass substrate arranged to face a surface of the silicon substrate and having a transparent electrode layer in its opposing surface; a light diffraction reflection layer aligned on a surface of the silicon substrate; a liquid crystal layer aligned between the light diffraction reflection layer and the transparent electrode layer; a silicon substrate electrical terminal extracted from a rear surface of the silicon substrate; and a means for applying voltage between the transparent electrode layer and the silicon substrate electrical terminal; wherein selection of wavelength of light diffracted and reflected by the light diffraction reflection layer is possible by controlling the refraction index of the liquid crystal layer through the voltage.

Abstract: To provide with a wavelength-selection optical switch able to select a light with a certain wavelength and an optical add/drop multiplexer using the same. An optical switch comprising: a silicon substrate; a glass substrate arranged to face a surface of the silicon substrate and having a transparent electrode layer in its opposing surface; a light diffraction reflection layer aligned on a surface of the silicon substrate; a liquid crystal layer aligned between the light diffraction reflection layer and the transparent electrode layer; a silicon substrate electrical terminal extracted from a rear surface of the silicon substrate; and a means for applying voltage between the transparent electrode layer and the silicon substrate electrical terminal; wherein selection of wavelength of light diffracted and reflected by the light diffraction reflection layer is possible by controlling the refraction index of the liquid crystal layer through the voltage.

Abstract: In order to reduce the sizes of a tunable optical filter and an external-resonator-type tunable semiconductor laser device, the filter includes: a silicon substrate; a glass substrate which is disposed opposed to the face of the silicon substrate and is equipped with a transparent electrode layer provided over the face thereof disposed to the substrate; an optical diffracting-and-reflecting layer disposed over the face of the silicon substrate; and a liquid crystal layer disposed between the optical diffracting-and-reflecting layer and the transparent electrode layer; and the filter is characterized in that in the filter where the refractive index of the liquid crystal layer is controlled by the voltage applied between the silicon substrate and the transparent electrode layer, a silicon-substrate-side electrode terminal for applying the voltage thereto is provided on the backside of the silicon substrate, this filter being assembled in the external-resonator-type tunable semiconductor laser device.

Abstract: An improved pickup cartridge of the kind including two moving coils is disclosed which is constructed such that a cantilever including a stylus tip at its foremost end is inclinably held by means of a damping rubber fixedly fitted into a longitudinally extending hole in a cartridge case which is preferably divided into two case halves and a pair of coils are wound about the cantilever which are located opposite to one another relative to the damper rubber disposed therebetween. An assembly of a magnet and yokes is fixedly held in the cartridge case so as to generate two magnetic fields which are directed at a right angle relative to one another, one of them being located corresponding to one of the coils and the other one being located corresponding to the other coil. Preferably, an assembly including the cantilever, the coils and the damper rubber is fitted into a sleeve and the latter is inserted in the longitudinally extending hole in the cartridge case.