Abstract: An optical module 1 comprises a first optical element F1, a first light receiving subassembly PD1, a second optical element F2, a second light receiving subassembly PD2, a light emitting subassembly LD3 for generating light, and a light transmitting part 3 optically coupled to the first optical element. The light emitting subassembly LD3, the first optical element F1, the second optical element F2 and the first light receiving subassembly PD1 are arranged along a predetermined plane S1. The light emitting subassembly LD3, the first optical element F1, the second optical element F2, and the second light receiving subassembly PD2 are arranged along another predetermined plane S2. The predetermined plane S1 intersects at a predetermined angle with the other predetermined plane S2.

Abstract: The present invention provides a semiconductor laser module in which parasitic inductance due to the bonding wire is removed, accordingly, the high frequency performance thereof can be enhanced. The laser module of the present invention has a sub-mount, on which the semiconductor laser diode is installed and transmission lines for supplying the signal to the laser diode is formed. The transmission lines on the sub-mount are directly connected to corresponding lead pins provided in the base of the package without any bonding wires. Between the lead pins and under the sub-mount is provided a photo diode for monitoring light emitted from the laser diode.

Abstract: An optical module comprising a column-shaped mounting member having a through hole extending along the central axis thereof and having a mounting surface formed by incising a part of the mounting member so as to expose the interior surface of the through hole; and an optical fiber inserted in the through hole and secured in a configuration such that the optical fiber protrudes with a specified length onto the mounting surface. The structure, in which a Bragg diffraction grating is formed in such protruding part of the optical fiber on said mounting surface, can prevent the occurrence of a change in reflective characteristic of the Bragg diffraction grating.

Abstract: The present invention provides an optical receptacle having a superior insertion/extraction performance of the ferrule, and an optical sub-assembly applying the optical receptacle. The optical receptacle 1 includes a stub, a bush 4, a sleeve, and a sleeve cover. The stub having a lower portion covered by the bush, and an upper portion covered by the sleeve. The sleeve may be a rigid sleeve without any slit along the optical axis in its outer surface. The sleeve cover covers the sleeve and the bush. In the present optical receptacle, the bush is press-fitted into the gap formed between the stub and the sleeve cover. Accordingly, in addition to the application of the rigid sleeve, not only the sub is hard to slide out from the sleeve, but also the insertion/extraction performance of the ferrule to be inserted into the sleeve may be enhanced.

Abstract: An optical transmission and receiver module suitable for a single-fiber bi-directional communication includes a light emitting device, a photodiode, an optical path routing element which allows light emitted from the light emitting device and light directed to the photodiode to pass through the element and which changes their optical paths, as required, and a lens transparent to both light emitted from light emitting device and light directed to the photodiode.

Abstract: 250 ?m is the standardized pitch H of the prevalent multichannel ribbonfibers. Current laser diodes and photodiodes have a size larger than 300 ?m. Curving lightpaths made on a silicon bench for reconciling the chip size with current ribbonfibers causes bending power loss, optical crosstalk and difficulty of production. Linear parallel lightpaths with a width d for more than one chip site are produced on a bench with a pitch E which is equal to the pitch H of the multichannels. Optoelectronic device chips with a width W satisfying an inequality E<W<2E?d are mounted on the lightpaths at spots which are different from neighboring chips in the longitudinal direction.

Abstract: A jointing holder for an optical module for single-fiber bidirectional communication comprises a unitarily structured cylindrical body that has the following portions: (a) an optical fiber-fixing portion for securely holding an optical fiber for transmitting multiwavelength light bidirectionally, (b) a semiconductor laser-fixing portion for securely holding a semiconductor laser for emitting outgoing light ?1, (c) a photodiode-fixing portion for securely holding a photodiode for receiving incoming light ?2, (d) an optical path-forming space for optically coupling the optical fiber, the semiconductor laser, and the photodiode, and (e) in the optical path-forming space, an optical filter-fixing face for securely holding an optical filter for separating multiplexed wavelengths. The jointing holder enables the optical module to reduce the number of components, to be miniaturized, and to reduce the dimensional deviation at the time of the assembly, enabling high-precision assembly.

Abstract: An optical communication device including optoelectronic (LD, PD, LD/PD) elements allocated to a top surface of a circuit board and electronic, electric elements (IC, R/C) allocated to a bottom surface and to the top surface of the circuit board.

Abstract: An optical module comprising a column-shaped mounting member having a through hole extending along the central axis thereof and having a mounting surface formed by incising a part of the mounting member so as to expose the interior surface of the through hole; and an optical fiber inserted in the through hole and secured in a configuration such that the optical fiber protrudes with a specified length onto the mounting surface. The structure, in which a Bragg diffraction grating is formed in such protruding part of the optical fiber on said mounting surface, can prevent the occurrence of a change in reflective characteristic of the Bragg diffraction grating.

Abstract: An optical receiver, small and inexpensive, is used for a WDM transmission system in place of a wavelength demultiplexer. In the receiver, a light-transmitting medium and a photodiode (PD) are placed on the same substrate, a wavelength-selecting filter is attached perpendicularly or obliquely to the end face of or to a cut section at the midpoint of the medium, the filter transmits only the assigned wavelength included in the incident light having multiplexed wavelengths, and the PD detects only the assigned wavelength. With an optical fiber, the fiber can be housed in a ferrule. In this case, the filter is inserted into a filter-supporting hole provided at a midpoint of the ferrule, the ferrule is fixed in a groove formed on the substrate, and an optical pathway-changing groove formed on the substrate reflects light having emerged from the optical fiber to introduce it into the PD.

Abstract: A jointing holder for an optical module for single-fiber bidirectional communication comprises a unitarily structured cylindrical body that has the following portions: (a) an optical fiber-fixing portion for securely holding an optical fiber for transmitting multiwavelength light bidirectionally, (b) a semiconductor laser-fixing portion for securely holding a semiconductor laser for emitting outgoing light ?1, (c) a photodiode-fixing portion for securely holding a photodiode for receiving incoming light ?2, (d) an optical path-forming space for optically coupling the optical fiber, the semiconductor laser, and the photodiode, and (e) in the optical path-forming space, an optical filter-fixing face for securely holding an optical filter for separating multiplexed wavelengths. The jointing holder enables the optical module to reduce the number of components, to be miniaturized, and to reduce the dimensional deviation at the time of the assembly, enabling high-precision assembly.

Abstract: An optical receiver includes an avalanche photodiode (APD) having a light-receiving area provided on a face of a first substrate, the light-receiving area receiving a part of signal light; a photodetector having a light-receiving area provided on a face of a second substrate, the light-receiving area receiving the other part of the signal light; and a mounting member having a principal plane on which the APD and the photodetector are mounted. Due to this structure, crosstalk between the APD and the photodetector does not occur and an avalanche multiplication factor of the APD can be controlled on the basis of the output current of the photodetector.

Abstract: The present invention relates to an optical module with a small size and improved mass-productivity. The optical module comprises a fiber stub including an optical fiber, a sleeve containing the fiber stub, and a semiconductor optical amplifying device. A Bragg fiber grating is formed in the optical fiber. The optical fiber is secured in the ferrule. The optical amplifying device and the grating form a laser cavity. Only a part of the hollow portion of the sleeve is filled with the fiber stub. One end face of the optical fiber is disposed at one end of the sleeve. The other end of the sleeve is hollow. The optical module acts as an optical receptacle. An optical plug can be inserted into the hollow end of the sleeve. This enables the laser light to be introduced into an external optical device.

Abstract: A photodiode (PD chip) includes a substrate, an absorption layer, a p-n junction in the absorption layer, a passivation film for protecting the end of the p-n junction, a p-electrode, and an n-electrode. The passivation film is covered with a protective layer composed of an insulative resin and having a thickness larger than that of the passivation film such that the passivation film of the PD chip fixed to the Si wafer and hence the p-n junction are not damaged or contaminated when an Si wafer including a number of horizontally and vertically arranged chip units, each having a V-groove for fixing an optical fiber, a marker, and a metallized pattern, is diced. Thus, a low-cost optical receiver module that does not generate dark current can be produced.

Abstract: An optical transmission module is constructed in a configuration wherein a semiconductor laser is mounted on a stem-side emitter loading portion of a pole provided on a stem and wherein light emitted forward from the semiconductor laser is outputted through a condenser lens and others. A monitor photodiode is mounted on a receiver loading portion of the pole on the forward side of the semiconductor laser and the photodiode detects part of the light emitted forward from the semiconductor laser, to monitor the operating condition of the semiconductor laser. This configuration achieves decrease in the length of a lead pin and thus restrains deterioration of the waveform of the drive current to the semiconductor laser.

Abstract: An optical communications module in which electrical crosstalk is reduced. The term “optical communications module” represents a surface-mounting-type optical tranceiver, transmitter, or receiver module. The optical communications module has a following structure. (a) An Si substrate carries at least one signal-transmitting section comprising an LD, at least one signal-receiving section comprising a PD, or both together with other components. (b) An insulating substrate is bonded to the back face of the Si substrate. (c) A separating groove separates the Si substrate along the or each boundary line between the sections in order to prevent an AC current flowing through the Si substrate. To attain this object, the separating groove is provided from the top surface of the Si substrate to some midpoint of the insulating substrate.

Abstract: An optical receiver comprises (a) an optical fiber, (b) a rear-illuminated type PD for receiving incoming light emerging from the optical fiber, (c) a submount supporting the PD, (d) a coaxial type package housing the submount, and (e) a preamplifier IC for amplifying electric signals from the PD. In particular, the submount is provided with a reflecting face for reflecting the incoming light so that the light can enter the PD. The submount may be provided with an optical path-forming groove having at least one reflecting face for introducing and reflecting the incoming light so that the light can enter the light-receiving portion of the PD mounted on the submount. This structure enables the production of an optical receiver most suitable for high-speed response and excellent in productivity. A method of producing the optical receiver is also offered.

Abstract: An optical receiver comprises a PD for receiving an incident light from an optical fiber, a preamplifier IC for amplifying an electrical signal from the PD, a submount on which the PD and the preamplifier IC are mounted on the same plane, and a package on which the submount is mounted. The PD and the preamplifier IC are directly connected to each other by a wire, and these components are both mounted on the same submount. Therefore, the distance between the PD and the preamplifier IC can be reduced, and parasitic inductance, parasitic capacitance, etc. can be greatly reduced. As a result, an optical receiver is provided which has reduced parasitic inductance and parasitic capacitance, and which is optimum for high speed response.

Abstract: In optical module 1a, substrate 3 has first and second regions 3a, 3b and first and second optical waveguides 3c, 3d. First and second regions 3a, 3b are arranged along a predetermined plane. First and second optical waveguides 3d, are provided in the first region 3a and extend in a direction of a predetermined axis. Semiconductor light emitting device 7 includes a semiconductor light emitting element 7a optically coupled to first optical waveguide 3c and provided in second region 3e. Semiconductor driving element 9 is electrically connected to semiconductor light emitting element 7a. Semiconductor driving element 9 is mounted on mount member 13. Optical element 15a reflects a part of incident light and transmits a part of the incident light, and semiconductor light receiving device 17 includes a light receiving element 17a provided in first region 3a so as to be optically coupled to optical element 15a.

Abstract: A light emitting device has a fiber stub component, a grating chip, a semiconductor optical amplifier, a photodiode, and a mount member. The fiber stub component is comprised of a ferrule and an optical fiber. The fiber stub component, grating chip, and semiconductor optical amplifier are mounted on the mount member and are optically coupled to each other. An optical cavity is comprised of a light reflecting surface of the semiconductor optical amplifier and a diffraction grating of the grating chip. In this configuration, the light emitting device can provide laser light of a desired wavelength, without use of a pigtail fiber. The light emitting device can be constructed in smaller size than those using the pigtail fiber.