Abstract: An optical device package comprises: a metal frame including a substrate and a rectangular die pad portion integrally connected to the substrate, wherein the substrate is a metal plate, and the die pad portion is bent from the substrate such that the die pad portion extends from the substrate at an angle of 90 degrees; signal lead pins extend in the opposite directions from the die pad portion relative to the substrate such that the first lead pins intersect the principal surfaces of the substrate at a right angle and are spaced apart from the metal frame; and a molded resin member including a plate-like resin base extending across and in contact with one of the principal surfaces of the substrate, wherein the signal lead pins protrude from a surface of the resin base; surfaces of the signal lead pins are covered with the molded resin member; and the metal frame and the signal lead pins are secured in place by the molded resin member.

Abstract: An optical device package comprises: a metal frame including a substrate and a rectangular die pad portion integrally connected to the substrate, wherein the substrate is a metal plate, and the die pad portion is bent from the substrate such that the die pad portion extends from the substrate at an angle of 90 degrees; signal lead pins extend in the opposite direction from the die pad portion relative to the substrate such that the first lead pins intersect the principal surfaces of the substrate at a right angle and are spaced apart from the metal frame; and a molded resin member including a plate-like resin base extending across and in contact with one of the principal surfaces of the substrate, wherein the signal lead pins protrude from a surface of the resin base; surfaces of the signal lead pins are covered with the molded resin member; and the metal frame and the signal lead pins are secured in place by the molded resin member.

Abstract: A semiconductor laser chip is joined to an AlN sub-mount in a junction-down manner. The sub-mount is joined to a package. The AlN sub-mount is joined to a stem. The direction perpendicular to the irradiation direction of a laser beam emitted from the semiconductor laser chip is the direction of the width of the sub-mount. The thickness and the width of the AlN sub-mount are determined so that the product of the equivalent stress applied to the center of the surface of the semiconductor laser chip joined to the sub-mount and the stress in the direction of the width of the sub-mount does not exceed 70% of the maximum value of the product obtained by changing the thickness and the width of the AlN sub-mount.

Abstract: An optical device package comprises: a metal frame including a substrate and a rectangular die pad portion integrally connected to the substrate, wherein the substrate is a metal plate, and the die pad portion is bent from the substrate such that the die pad portion extends from the substrate at an angle of 90 degrees; signal lead pins extend in the opposite direction from the die pad portion relative to the substrate such that the first lead pins intersect the principal surfaces of the substrate at a right angle and are spaced apart from the metal frame; and a molded resin member including a plate-like resin base extending across and in close contact with one of the principal surfaces of the substrate, wherein the signal lead pins protrude from a surface of the resin base; surfaces of the signal lead pins are covered with the molded resin member; and the metal frame and the signal lead pins are secured in place by the molded resin member.

Abstract: A semiconductor laser chip is joined to an AlN sub-mount in a junction-down manner. The sub-mount is joined to a package. The AlN sub-mount is joined to a stem. The direction perpendicular to the irradiation direction of a laser beam emitted from the semiconductor laser chip is the direction of the width of the sub-mount. The thickness and the width of the AlN sub-mount are determined so that the product of the equivalent stress applied to the center of the surface of the semiconductor laser chip joined to the sub-mount and the stress in the direction of the width of the sub-mount does not exceed 70% of the maximum value of the product obtained by changing the thickness and the width of the AlN sub-mount.

Abstract: An optical device package comprises: a metal frame including a substrate and a rectangular die pad portion integrally connected to the substrate, wherein the substrate is a metal plate, and the die pad portion is bent from the substrate such that the die pad portion extends from the substrate at an angle of 90 degrees; signal lead pins extend in the opposite direction from the die pad portion relative to the substrate such that the first lead pins intersect the principal surfaces of the substrate at a right angle and are spaced apart from the metal frame; and a molded resin member including a plate-like resin base extending across and in close contact with one of the principal surfaces of the substrate, wherein the signal lead pins protrude from a surface of the resin base; surfaces of the signal lead pins are covered with the molded resin member; and the metal frame and the signal lead pins are secured in place by the molded resin member.

Abstract: A substrate holder employed for MOCVD and supporting a wafer on which crystal growth proceeds includes a molybdenum holder body, a GaAs polycrystalline film with a flat surface grown on a part of the surface of the molybdenum holder body where the wafer is absent, and an InP polycrystalline film grown on the GaAs polycrystalline film. Each of the polycrystalline films is grown to a thickness of 0.3 .mu.m or more at a temperature higher than the epitaxial growth temperature of 575.degree. C. During the MOCVD process, the emissivity of the molybdenum substrate holder is stable at a value near the emissivity of the wafer on the substrate holder and, therefore, the decomposition ratio of PH.sub.3 gas on the substrate holder is stable at a value near the decomposition ratio on the wafer, whereby any variation of the incorporation ratio of P atoms in the grown InGaAsP, i.e., a variation of the composition of the InGaAsP, is reduced and run-to-run variations of the composition of the grown crystal are reduced.

Abstract: A method for fabricating a semiconductor laser includes forming a double heterojunction structure on a first conductivity type semiconductor substrate; forming the double heterojunction structure into a stripe mesa shape by selective etching; successively growing a first conductivity type layer, a second conductivity type current blocking layer, and a first conductivity type current blocking layer on opposite sides of the mesa to embed the mesa; and adding an impurity from a surface of the first conductivity type current blocking layer to form impurity doped regions that electrically separate the second conductivity type current blocking layer from an upper part of the mesa at opposite sides of the mesa.

Abstract: A semiconductor laser includes a first conductivity type semiconductor substrate; a double-heterojunction structure including a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer successively disposed on the semiconductor substrate; two parallel stripe grooves forming the double-heterojunction structure in a mesa shape; a first conductivity type mesa embedding layer, a second conductivity type current blocking layer, and a first conductivity type current blocking layer successively disposed on the semiconductor substrate and contacting opposite sides of the mesa; and impurity doped regions formed by adding an impurity through the surface of the first conductivity type current blocking layer. The impurity doped regions electrically separate an upper part of the mesa from the second conductivity type current blocking layer at opposite sides of the mesa.

Abstract: An antenna device for a direction finder includes a substantially grounded conductive base plate, a plurality of web-shaped antenna elements mounted in spaced relation on the base plate and having central portions extending in crisscross relation and insulated from each other, an electronic switching circuit for alternately grounding ends of the antenna elements and picking up reception outputs from opposite ends of the antenna elements at a constant period with the antenna elements being switched out of phase at an angle corresponding to the angle at which the antenna elements extend across each other, and a circuit for combining outputs from the antenna elements. According to another embodiment, the antenna elements comprise the web-shaped antenna elements and a vertical antenna element disposed substantially centrally in the web-shaped antenna elements.

Abstract: An automatic direction finder capable of measuring a direction with a higher accuracy is disclosed. In an initial measurement, loop antennas and a vertical antenna are used in a conventional manner. However, in a final measurement the vertical antenna adversely affected by the surrounding disturbances is not employed and only the loop antennas are used. The disclosed finder includes a switching device for disconnecting the vertical antenna in the final measurement. The finder is also provided with a pair of search coils disposed perpendicular to each other. One of the search coils is connected to a combining circuit via the switching device, while the other is connected to the combining circuit via a balanced modulator.

Abstract: In an antenna device for a direction finder including an electrically conductive antenna plate of a configuration symmetrical around its center and disposed in parallel with a base plate with a predetermined distance maintained therebetween, a plurality of pairs of connecting portions are provided around the antenna plate so that one in each pair is provided opposite to the other with respect to the center. An electronic switch provided in the device transfers the connection in order that one in a pair thus transferred is grounded through a resistor having the characteristic impedance of the antenna plate while the other in the pair is connected to the receiver of the direction finder through a cable having the characteristic impedance.

Abstract: An automatic direction finder for automatically finding the arriving direction of electric waves by rotating a goniometer or the like with the use of a stepping motor is described. The stepping motor is controlled by means of a digital circuit using a reversible counter. The polarities of the phase of the output demodulated by a receiving circuit are detected in terms of the antinodes thereof.

Abstract: A radio direction finder, which is designed to determine the direction of arrival of a radio wave by causing the rotation of a directional antenna arrangement or a goniometer, to which the output of the directional antenna arrangement is coupled, or rotating the directivity by an electric means and combining the output of the directional antenna arrangement or goniometer and the output of a non-directional antenna. With this system, it is possible to detect and display the bearing of the received radio wave with a higher place counter and precisely track and display the second bearing of the wave with a lower place counter.

Abstract: A radio direction finder, designed to determine the direction of arrival of radio waves utilizing a nondirectional antenna and a plurality of directional antennas having respective directivities, comprises an oscillator for producing A.C. signals having a phase angle in correspondence to the configuration of each of the directional antennas, modulators for modulating the respective outputs of the directional antennas with respective A.C. signals, a additive circuit for superimposing the respective modulation outputs on the phase-shifted output of the nondirectional antenna, and a receiving circuit for demodulating the added output of the additive circuit to recover the A.C. signals. The radio direction finder is further characterized by an automatic phase tracking counter for following the phase of the output of the receiving circuit, and a display unit for displaying the bearing of the received radio wave numerically.

Abstract: An automatic direction finder wherein a loop antenna is fitted within a combined handle and index rotatably pivoted at the center of a direction dial, a gear of a diameter large enough is fixed to said index and a pinion meshing with said gear is connected through a frictional power transmission with a direct current servomotor to which an automatically controlled output of said antenna obtained from the output of said antenna is given.