Abstract: The present invention provides a multimode semiconductor laser module. The module comprises a multimode laser element 34, an optical filter 54, a light-receiving element 52 and a temperature regulator 24. Multimode light from the laser element 34 is transmitted through the filter 54 and then detected by the light-receiving element 52. The output of the light-receiving element 52 changes according to the degree of overlap between the oscillation wavelength spectrum of the laser element 34 and the transmission wavelength region of the filter 54. The temperature regulator 24 modifies the oscillation wavelength region toward the desired region in response to the output of the light-receiving element 52. As a result, the oscillation wavelength region is stabilized.

Abstract: A multimode light generating module comprises an optical cavity and a light-receiving element. The optical cavity is constituted by a semiconductor optical amplification element, and an optical fiber having a grating. The optical fiber comprises a grating having an apodized periodic refractive index distribution, and the slope of the reflection spectrum in a longer wavelength region with respect to the peak wavelength ?p is gentler than that in the shorter wavelength region therewith. The grating satisfies the relationship of 0.5 nm>?0.2??p>0.1 nm. Here, ?0.2 is defined by ?0.2h-?0.2l, where ?0.2h is the longer one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity, and ?0.2l is the shorter one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity.

Abstract: A main portion 10 of an optical module 1 includes a thermoelectric cooler 21, and a chip carrier 22b placed on the cooler 21. A semiconductor light-emitting device 31, a lens 32, photodetectors 33a, 33b, and an etalon 34 are directly or indirectly mounted on the chip carrier 22b. Supporting members 36a and 36b are also fixed on the chip carrier 22b. A roof 35 is supported by the supporting members 36a, 36b and positioned above the etalon 34. The roof 35, supporting members 36a, 36b and chip carrier 22b are maintained at substantially equal temperatures by the cooler 21. As a result, the temperature of the etalon 34 is stabilized, and therefore the variation in the lock wavelength is suppressed.

Abstract: A multimode light generating module comprises an optical cavity and a light-receiving element. The optical cavity is constituted by a semiconductor optical amplification element, and an optical fiber having a grating. The optical fiber comprises a grating having an apodized periodic refractive index distribution, and the slope of the reflection spectrum in a longer wavelength region with respect to the peak wavelength &lgr;p is gentler than that in the shorter wavelength region therewith. The grating satisfies the relationship of 0.5 nm>&lgr;0.2−&lgr;p>0.1 nm. Here, &lgr;0.2 is defined by &lgr;0.2h−&lgr;0.21, where &lgr;0.2h is the longer one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity, and &lgr;0.21 is the shorter one of two wavelengths exhibiting a relative reflectivity of 0.2 with respect to the maximum reflectivity.

Abstract: A main portion 10 of an optical module 1 includes a thermoelectric cooler 21, and a chip carrier 22b placed on the cooler 21. A semiconductor light-emitting device 31, a lens 32, photodetectors 33a, 33b, and an etalon 34 are directly or indirectly mounted on the chip carrier 22b. Supporting members 36a and 36b are also fixed on the chip carrier 22b. A roof 35 is supported by the supporting members 36a, 36b and positioned above the etalon 34. The roof 35, supporting members 36a, 36b and chip carrier 22b are maintained at substantially equal temperatures by the cooler 21. As a result, the temperature of the etalon 34 is stabilized, and therefore the variation in the lock wavelength is suppressed.

Abstract: The present invention provides a multimode semiconductor laser module. The module comprises a multimode laser element 34, an optical filter 54, a light-receiving element 52 and a temperature regulator 24. Multimode light from the laser element 34 is transmitted through the filter 54 and then detected by the light-receiving element 52. The output of the light-receiving element 52 changes according to the degree of overlap between the oscillation wavelength spectrum of the laser element 34 and the transmission wavelength region of the filter 54. The temperature regulator 24 modifies the oscillation wavelength region toward the desired region in response to the output of the light-receiving element 52. As a result, the oscillation wavelength region is stabilized.

Abstract: A semiconductor laser module has a semiconductor light-emitting device and an optical fiber provided with a diffraction grating. The diffraction grating is a chirped grating having a refractive index with a period continuously changing along the optical axis direction (light-guiding direction) of optical fiber, whereas the amplitude of refractive index of the chirped grating changes so as to draw an envelope (apodization curve) along the light-guiding direction. The period of refractive index of chirped grating becomes the shortest on the side closer to the semiconductor light-emitting device and successively expands along the propagating direction of laser light (light-guiding direction). Consequently, the reflection spectrum characteristic of diffraction grating mildly changes with a single peak in a region having a width not narrower than the half width of reflection spectrum, whereby a plurality of peaks are restrained from occurring in the reflection spectrum characteristic.

Abstract: A fiber grating laser module comprises a semiconductor optical amplifier and a grating fiber in which a Bragg grating is formed in the core. The semiconductor optical amplifier provides a wave guide in which the light is generated and amplified by the carrier injection, the light emitting facet and the light reflecting facet. The Bragg grating in the grating fiber and the light reflecting facet of the semiconductor amplifier forms an optical resonator. The subject of the invention is that the reflectance of the Bragg grating at the Bragg diffraction wavelength is greater than 60%.

Abstract: A semiconductor laser module includes a semiconductor laser having an active region between a light-reflecting surface and a light-exit surface thereof, and an optical fiber optically coupled to the semiconductor laser and including an optical fiber diffraction grating. The optical fiber diffraction grating selectively reflects light within a predetermined wavelength band. The wavelength band has a width larger than a wavelength interval of a longitudinal mode of light resonating between the light-reflecting surface and the light-exit 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: 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 light receiving module and its manufacturing method of an excellent structure which can make a good and uniform optical couple between an optical fiber and a light receiving element, and can improve its productivity. The light receiving module comprises a semiconductor substrate, a light receiving element mounted on a surface of the semiconductor substrate, a groove formed on a back surface of the semiconductor substrate, an inclined face in the back surface side facing the light receiving element, and an optical fiber fixed in the groove. A transmitted light signal through the fiber is reflected by the inclined face. The inclined face is formed at a distal end of the optical fiber, at the closed end wall of the groove, or a side wall of a dimple arranged on the extension line of the groove. The reflected light is admitted to a light receiving face of the light receiving element, from the back surface side of the semiconductor substrate.

Abstract: A photodetector of the present invention is devised to reduce the dark current by employing a novel guard ring structure suitable for a mesa type photodiode (PD). Namely, the PD of the present invention has the structure in which a p-type or n-type semiconductor region which is to be a light receiving area is surrounded by a semiconductor region (guard ring) of the same conduction type. A guard ring electrode is formed on the guard ring region and is kept at the same potential as an electrode on a region desired to reduce the dark current. Also, an opto-electronic integrated circuit of the present invention has such a structure that a PD, which is the photodetector of the present invention, and a circuit element such as a transistor are formed on a common semiconductor substrate and that an anode electrode or a cathode electrode of the PD is conductively connected to a gate electrode of a field-effect transistor or to a base electrode of a bipolar transistor.

Abstract: There is disclosed on optoelectronic integrated circuit comprising, a plurality of channels each including an optical receiving device for converting a received optical signal to an electric signal, and an amplifier for amplifying an output signal of the optical receiving device, the channels being integrated on the same semiconductor substrate, electric power source nodes of at least two of the amplifiers of the respective channels being connected to a common electric power source node, and the common electric power source node being connected through a resistor element to an electric source power supply terminal for supplying an electric source power to the channels.

Abstract: A photodetector of the present invention is devised to reduce the dark current by employing a novel guard ring structure suitable for a mesa type photodiode (PD). Namely, the PD of the present invention has the structure in which a p-type or n-type semiconductor region which is to be a light receiving area is surrounded by a semiconductor region (guard ring) of the same conduction type. A guard ring electrode is formed on the guard ring region and is kept at the same potential as an electrode on a region desired to reduce the dark current. Also, an opto-electronic integrated circuit of the present invention has such a structure that a PD, which is the photodetector of the present invention, and a circuit element such as a transistor are formed on a common semiconductor substrate and that an anode electrode or a cathode electrode of the PD is conductively connected to a gate electrode of a field-effect transistor or to a base electrode of a bipolar transistor.

Abstract: A light receiving module and its manufacturing method of an excellent structure which can make a good and uniform optical couple between an optical fiber and a light receiving element, and can improve its productivity. The light receiving module comprises a semiconductor substrate, a light receiving element mounted on a surface of the semiconductor substrate, a groove formed on a back surface of the semiconductor substrate, an inclined face in the back surface side facing the light receiving element, and an optical fiber fixed in the groove. A transmitted light signal through the fiber is reflected by the inclined face. The inclined face is formed at a distal end of the optical fiber, at the closed end wall of the groove, or a side wall of a dimple arranged on the extension line of the groove. The reflected light is admitted to a light receiving face of the light receiving element, from the back surface side of the semiconductor substrate.

Abstract: There is disclosed a photo-electronic integrated circuit device comprising a first and second output terminals for supplying first and second output signal of opposite polarities to an external differential input logic circuit, a photo-detecting device for converting an input light signal to an electrical signal, a first amplifier for amplifying the electrical signal of the photo-detecting device and outputting the same from the first output terminal as the first output signal, and a second amplifier for amplifying the output of the first amplifier and outputting the second output signal having the opposite phase to that of the first output signal, from the second output terminal.

Abstract: Present invention is to provide a process for producing an opto-electronic integrated circuit comprising a field effect transistor as an electronic device and a photo-diode as an optical device both formed on an InP substrate,the field effect transistor comprising a high electron mobility transistor having:a GaInAs layer epitaxially grown in the InP substrate in a preset region thereof, a n-AlInAs layer epitaxially grown on the GaInAs layer, a gate electrode formed on the AlInAs layer, and a source electrode and a drain electrode formed on the AlInAs layer with the gate electrode therebetween, andthe photo-diode comprising a PIN photo-diode having:the GaInAs layer epitaxially grown on the InP substrate near the region of the field effect transistor simultaneously with the growth of that of the field effect transistor, the n-AlInAs layer epitaxially grown on the GaInAs layer simultaneously with the growth of that of the field effect transistor, a n-InP layer epitaxially grown on the n-AlInAs layer, an undoped

Abstract: There is disclosed a method of manufacturing an integrated circuit, comprising: the first step of growing a first epitaxial crystal on a compound semiconductor substrate, removing an unnecessary region of the first epitaxial crystal to form a residual portion, and covering the residual portion with a selective growth mask, the second step of growing a second epitaxial crystal on an exposed substrate portion, removing an unnecessary portion of the second epitaxial crystal to form a residual portion of the second epitaxial crystal, and covering the residual portion of the second epitaxial crystal with a selective growth mask, and third step of growing a third epitaxial crystal on an exposed substrate portion and removing an unnecessary region of the third epitaxial crystal, wherein the first to third epitaxial crystal form any one of a pin photodiode crystal, a heterojunction bipolar transistor crystal, and a high electron mobility transistor crystal, and are different from each other.