Rohm Co., Ltd.

Masahiko Tsumori

Haruo Tanaka

Tomohiro Yamazaki

An optical transceiver is equipped with at least one coupling lens which condenses reception signal light from an optical medium and condenses transmission signal light to the optical medium, an optical plate which passes the reception signal light and reflects the transmission signal light, a light receiving element which receives the reception signal light passed through the optical plate, and a light emitting element which transmits the transmission signal light so as to be reflected by the optical plate, wherein an emission port of the transmission signal light of the light emitting element is arranged at a position to enable the transmission signal light from the light emitting element to form an image in the optical medium via the optical plate and the coupling lens, and wherein the emission port of the transmission signal light of the light emitting element is arranged in a direction that makes the incident angle formed on the optical plate by the beam center line of the transmission signal light transmitted from the light emitting element larger than the incident angle of the beam center line for maximally condensing the transmission signal light from the light emitting element to the optical medium in order to move the beam center line of the transmission signal light from the light emitting element away from the light receiving element, whereby it becomes possible to reduce the near-end crosstalk from the light emitting element to the light receiving element in the optical transceiver.

Optical transceiver

An optical transmitter is equipped with a laser diode and a light detector provided on a packaging base, in which the light detector has a semiconductor substrate side arranged on a packaging base side, a semiconductor junction plane, a side surface which is roughly orthogonal to the semiconductor junction plane, and a facing surface which faces the side surface, wherein the facing surface is partially or completely inclined to reflect the output light from the laser diode incident from the side surface to the semiconductor junction plane of the light detector.

Optical transmitter having photodiode

A light emitting portion ( ) and an objective lens ( ) for collecting a light of the light emitting portion are provided. The light receiving portion ( ) is provided in the vicinity of the light emitting portion ( ) such that the light can be collected by the objective lens and the light reflected by an optical disk ( ) to be an object can be detected. The light emitting portion and the light receiving portion are formed to get in a range of 1.22 &lgr;/NA (beam waist BW) wherein a numerical aperture of the objective lens is represented by NA and a wavelength of the light emitting portion is represented by &lgr; or the light receiving portion is multi-split such that a focal shift of a beam having an astigmatism formed thereon can be detected. As a result, it is possible to obtain a light receiving and emitting compound element capable of surely detecting a focal position without adjusting a positional relationship between the light emitting portion and the light receiving portion and an optical pick-up device capable of being easily assembled and of detecting and correcting a shift in a focus or a tracking with a high sensitivity.

Light receiving and emitting compound element and optical pick-up device using the same

A module for bidirectional optical communication includes: a light emitting element for emitting transmitting signal light of the 1.3 &mgr;m band and directing the light to an optical transmission line made of optical fibers, for example; a light receiving element having light receiving portions for receiving respectively receiving signal light of the 1.3 &mgr;m band and that of the 1.55 &mgr;m band which are sent from the optical transmission line; and an optical branching filter interposed between the light emitting element and the light receiving element, and the optical transmission line. The optical branching filter has four different dielectric film portions which split the receiving signal light into 1.3 &mgr;m band light and 1.55 &mgr;m band light and have respective adjusted reflectances and transmittances, to allow signal light beams of different wavelength bands to be received separately. The resultant module for bidirectional optical communication is of a simple and inexpensive one-packaged structure capable of receiving signals of two different wavelength bands.

Growing community of inventors

Kyoto, Japan

Masahiko Tsumori