Abstract: Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24.

Abstract: Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24.

Abstract: The present invention provides an optical module, in which aligning adjustment is much easier than conventional module while a high optical coupling efficiency between an optical fiber and a semiconductor device is maintained. The module comprises a structure for effectively suppressing the decrease in optical coupling efficiency caused by changes in ambient temperature. The optical module comprises an optical reflecting member having a reflecting surface with a concave surface form for optically coupling the optical fiber and the semiconductor device to each other, and a deterioration-suppressing structure in which the change in shape of the reflecting member caused by changes in ambient temperature effectively suppresses the deterioration in optical coupling state between the optical fiber and semiconductor device due to changes in temperature or the like.

Abstract: A bonding method for effectively preventing once-adjusted members from positionally deviating is disclosed. In this method, when applied to a method of making an optical module in particular, a holding member such as a magnet which generates a magnetic force against a housing is attached to, and a relative position of an optical reflecting member once adjusted by the holding member is held. As a result of this configuration, the optical reflecting member is effectively prevented from positionally deviating.

Abstract: The present invention relates to an optical module having a configuration in which centering adjustment can be effected much more easily than the prior art, while keeping a high optical coupling efficiency between an optical fiber and a semiconductor device, and can reduce the number of parts, for example; and a method of making the same. The optical module comprises, as an element for optically coupling the optical fiber and the semiconductor device together, an optical reflecting member having a concave reflecting surface. Since it is necessary for the reflecting member to be positioned with a high accuracy in the field of optical communications to which this optical module is supposed to be utilized, in particular, the reflecting member is provided with a specific positioning configuration.

Abstract: A plurality of n-channel FETs in predetermined combinations are grouped two by two into pairs, and their respective gates and sources are connected to each other in a crossing manner, thus forming a first current mirror circuit connected to a higher-potential side power supply. A second current mirror circuit constituted by another plurality of n-channel FETs, diodes, and a variable resistor, which is connected to a lower-potential side power supply, is connected to the first current mirror circuit connected to the higher-potential side power supply, thereby forming a reference voltage generating circuit which generates a constant voltage. Further, three other pieces of n-channel FETs biased by this constant voltage, a diode, and the like constitute a light emitting element driving circuit for driving a light emitting element.

Abstract: It is an object of the present invention to provide a highly reliable optical module circuit board having a sufficient mechanical strength with respect to an external stress.

Abstract: A pin type light-receiving device according to the present invention comprises (a) a semiconductor substrate, (b) a first semiconductor layer formed on a semiconductor substrate and doped with an impurity of a first conduction type, (c) a second semiconductor layer formed in a mesa shape on the first semiconductor layer and made of a first semiconductor material without intentionally doping the first semiconductor material with an impurity, (d) a third semiconductor layer formed in a mesa shape on the second semiconductor layer and made of the first semiconductor material doped with an impurity of a second conduction type different from the first conduction type, (e) a first electrode layer formed in ohmic contact on the first semiconductor layer, (f) a second electrode layer formed in ohmic contact on the third semiconductor layer, and (g) a fourth semiconductor layer formed around the first to the third semiconductor layers and made of a second semiconductor material having a band gap energy greater than th

Abstract: It is an object of present invention to provide a low-cost photoelectric conversion module in which a signal for compensating noise caused by changes in temperature and variations in power supply is obtained. In the photoelectric conversion module according to the present invention, a first amplifier having an input terminal connected to the anode of a light-receiving element for converting an optical signal into an electrical signal amplifies the electrical signal to obtain an amplified signal. A second amplifier having an input terminal connected to one electrode of a capacitor outputs an amplified signal for compensating noise of the electrical signal amplified by the first amplifier. The other electrode of the capacitor is connected to the cathode of the light-receiving element. The capacitor has a capacitance value equal to the capacitance of the light-receiving element.

Abstract: It is an object of the present invention to provide an optical module having a structure in which alignment precision of sleeves to be accommodated to a housing can be improved with a simple operation. The optical module according to the present invention is characterized by providing special structures for defining the positions of the sleeves to a sleeve holder for holding the sleeves, and the housing having a cavity for accommodating the sleeves. In particular, the housing includes support portions each having a reference surface for defining the fixing position of the corresponding sleeve. The sleeve holder includes spring pieces each for urging the sleeve to the reference surface.

Abstract: In an optical link apparatus of the present invention, a hybrid IC which is a main amplifier of a receiver circuit, and a hybrid IC which is a transmitter circuit are mounted on an island of a lead frame. An OEIC in which electronic devices and a light receiving device which constitute a preamplifier of the receiver circuit are integrated is housed in a light receiving device unit. A light emitting device is housed in a light emitting device unit. Sleeves which are optical link components are installed at the light receiving device unit and the light emitting device unit, and one ends of the sleeves are protruded from a plastic molding to the outside. As wires are connected to lead pins, the hybrid ICs are electrically connected with the light receiving device unit and the light emitting device unit. The lead pins, the hybrid ICs, the light receiving device unit, the light emitting device unit, and the sleeves are integrally sealed by a plastic molding which is superior in productivity and processability.

Abstract: A photographic film processing apparatus having a processing unit placed in a water tank and provided with a plurality of processing chambers each having a comparatively small volume, and capable of uniformly, stably, continuously and quickly processing various types of films including superhigh-speed films requiring a plurality of film processing steps requiring different reaction times respectively and color films using small quantities of processing solutions. The processing unit is formed by arranging a plurality of pairs of film conveying rollers at given small intervals along an upward concave arc of a circle, closing spaces between the adjacent pairs of film conveying rollers by pairs of sealing rollers, and disposing a pair of support plates provided with ports on the opposite sides of the rollers respectively so as to define processing chambers of small volumes between the adjacent pairs of film conveying rollers and to be arranged successively along the direction of travel of a film (F).

Abstract: In an opto-electronic integrated circuit of the present invention, in a first surface region of a semiconductor substrate, a pin-type photodiode is constituted on the basis of a photodiode layer formed on a first transistor layer. In a second surface region of the semiconductor substrate, a heterojunction bipolar transistor is constituted on the basis of only a second transistor layer separated form the first transistor layer. Since a plurality of heterojunction bipolar transistors are normally integrated for one pin-type photodiode, the thickness of the heterojunction bipolar transistors larger in number than the pin-type photodiode is set regardless of the thickness of the pin-type photodiode. The thickness of a high-resistance layer in the pin-type photodiode is set with an increased degree of freedom.

Abstract: An opto-electronic integrated circuit is arranged to comprise a photodetector and a tunnel emitter bipolar transistor for first-stage amplification of a current generated in the photodetector, as formed on a substrate. The tunnel emitter bipolar transistor can be operated at high speed and has a high amplification factor, so that noise due to the base current can be reduced upon amplification of the current generated in the photodetector by light detection.

Abstract: A photographic film processing apparatus comprises a water tank for containing a constant quantity of fresh water, and one or a plurality of processing units each comprising a pair of feed rollers disposed with their circumferences in close contact with each other, a pair of delivery rollers spaced apart from the pair of feed rollers and disposed with their circumferences in close contact with each other, a pair of sealing rollers disposed with the circumference of one of them in close contact with the circumferences of the top feed roller and the top delivery roller and with the circumference of the other in close contact with the circumferences of the bottom feed roller and the bottom delivery roller, and a pair of support plates disposed respectively on the opposite sides of the rollers so as to support the rollers for rotation and to define a liquid-tight processing chamber by the circumferences of the rollers and the inner surfaces thereof.