Abstract: The present invention is related to an optical communication module for transmitting high frequency signals (e.g., 10 Gbit/s and higher data rates) between an optical element and an external circuit. In an illustrative embodiment, the optical communication module includes signal transmission lines and ground lines formed on a ceramic substrate, a flexible wiring board, and a printed circuit board. The widths of the signal lines and the ground lines vary, as well as the spacing between the signal and ground lines. This facilitates characteristic impedance matching among the signal lines to within about 50?.

Abstract: An object of disclosed technology is to control lasing wavelengths so that a wavelength shift does not occurs. Another object is to permit wavelengths of a light source for wavelength division multiplexing optical-fiber communication system to be variable in response to an ITU-TS grid. A means for achieving the objects is as follows: locating an etalon in a light path of diode laser light, which is a parallel plane wave changed by a collimator lens; generating a wavelength error signal from a difference between both of divided pieces of light from transmitted light or reflected light; and locking a wavelength of a diode laser device according to the wavelength error signal.

Abstract: A ceramic substrate is provided through a stem of a can-package, the desired number of wirings including the high speed signal wirings are formed on this ceramic substrate and the necessary electronic components other than a light-emitting/photosensitive element such as driver LSI and amplifying LSI or the like are also accommodated within the can-package.

Abstract: An object of disclosed technology is to control lasing wavelengths so that a wavelength shift does not occurs. Another object is to permit wavelengths of a light source for wavelength division multiplexing optical-fiber communication system to be variable in response to an ITU-TS grid. A means for achieving the objects is as follows: locating an etalon in a light path of diode laser light, which is a parallel plane wave changed by a collimator lens; generating a wavelength error signal from a difference between both of divided pieces of light from transmitted light or reflected light; and locking a wavelength of a diode laser device according to the wavelength error signal.

Abstract: An optical waveguide 3 comprises a substrate like a Si substrate having a projection with a flat surface and inclined side surfaces thereon, a buffer layer having a refractive index of n.sub.0 formed on lower surfaces of the substrate, a secondary buffer layer having a refractive index of n.sub.0 formed on the buffer layer, a core waveguide having a refractive index of n.sub.1 formed on the secondary buffer layer and a cladding layer having a refractive index of n.sub.0 covering the core waveguide. The flat surface of the projection 31 is exposed through an opening. The secondary buffer layer controls a transmission loss increase caused by partial thickness differences of the ground buffer layer or scattering by scratches or strains created by the grind.

Abstract: A facsimile apparatus has a transparent plate on which a document may be located. The document is then scanned by a scanner which includes electronic solid state light generation means e.g. LEDs which illuminate the document, with the light reflected from the document being detected by a detector. An electronic signal corresponding to an image of the document may then be transmitted to a remote location. Alternately, the facsimile apparatus may be used to copy the document. Cut paper sheets are withdrawn from storage and an image printed thereon by a heat transfer system in which a film of ink is selectively heated. Paper on which an image has been printed is then received on the upper surface of the storage. The facsimile apparatus may also have a document transporter for moving a document past the scanner with the scanner fixed.

Abstract: An impedance for short-circuit prevention is connected with a secondary winding side of a transformer of a resonant converter comprising a resonant circuit, a D.C. input source, and a switching devices. The short-circuit prevention impedance is driven by the driving current generated in a driving winding in accordance with a resonance current at the primary winding side of the transformer, thereby obviating the stop of an oscillation. The oscillation can be stopped at a timing of not generating a surge voltage in the switching devices by detecting a current returning to the D.C. input power source.