Abstract: An optical module includes a semiconductor optical device in which an active layer located at one side, an electrode located at the same side, and a mirror that reflects light toward the side opposite the electrode are monolithically integrated, a sub-mount having one surface on which a first wiring pattern is formed, a substrate in which an optical waveguide and a grating coupler are formed in a surface layer of the substrate, a spacer having an upper surface on which a second wiring pattern is formed, and a wire. The sub-mount is mounted on the spacer. The first wiring pattern on the sub-mount faces part of the second wiring pattern on the spacer and is electrically connected thereto. The second wiring pattern on the spacer includes a pad being disposed in a region exposed from the sub-mount and being bonded to the wire.

Abstract: An optical module includes a semiconductor optical device in which an active layer located at one side, an electrode located at the same side, and a mirror that reflects light toward the side opposite the electrode are monolithically integrated, a sub-mount having one surface on which a first wiring pattern is formed, a substrate in which an optical waveguide and a grating coupler are formed in a surface layer of the substrate, a spacer having an upper surface on which a second wiring pattern is formed, and a wire. The sub-mount is mounted on the spacer. The first wiring pattern on the sub-mount faces part of the second wiring pattern on the spacer and is electrically connected thereto. The second wiring pattern on the spacer includes a pad being disposed in a region exposed from the sub-mount and being bonded to the wire.

Abstract: An optical module includes a semiconductor optical device in which an active layer located at one side, an electrode located at the same side, and a mirror that reflects light toward the side opposite the electrode are monolithically integrated, a sub-mount having one surface on which a first wiring pattern is formed, a substrate in which an optical waveguide and a grating coupler are formed in a surface layer of the substrate, a spacer having an upper surface on which a second wiring pattern is formed, and a wire. The sub-mount is mounted on the spacer. The first wiring pattern on the sub-mount faces part of the second wiring pattern on the spacer and is electrically connected thereto. The second wiring pattern on the spacer includes a pad being disposed in a region exposed from the sub-mount and being bonded to the wire.

Abstract: An optical module includes a semiconductor optical device in which an active layer located at one side, an electrode located at the same side, and a mirror that reflects light toward the side opposite the electrode are monolithically integrated, a sub-mount having one surface on which a first wiring pattern is formed, a substrate in which an optical waveguide and a grating coupler are formed in a surface layer of the substrate, a spacer having an upper surface on which a second wiring pattern is formed, and a wire. The sub-mount is mounted on the spacer. The first wiring pattern on the sub-mount faces part of the second wiring pattern on the spacer and is electrically connected thereto. The second wiring pattern on the spacer includes a pad being disposed in a region exposed from the sub-mount and being bonded to the wire.

Abstract: In pattern synchronization for correctly regenerating received data, which is performed in an optical receiver for receiving an optical signal that has been subjected to quadrature phase modulation, signal conduction is quickly established without using duplicate combinations of bit shifting and pattern changing. A control method that does not involve verifying the duplicate combinations generated in modulation formats and pattern synchronization search orders. Specifically, a signal check circuit (40) performs data verification of data multiplexed by a MUX circuit (38) for multiplexing two data strings, and a bit shift pattern change control circuit (41) controls a bit shift circuit (36) and a pattern changing circuit (37) based on a result of the data verification and detects a correct combination of correct regenerated data to establish the signal conduction. At this time, for the bit shift circuit (36) and the pattern changing circuit (37), the duplicate combinations are not verified.

Abstract: An optical module includes: an optical module main body including an optical connector to which a communication cable transferring optical signal is connected, and a terminal portion on which a plurality of terminal pads for transmitting and receiving an electric signal for communication using the optical signal are arranged; a lead array including a lead fixing portion that retains a plurality of metal leads arranged in parallel on and protruding from the lead fixing portion and electrically connected to the plurality of terminal pads of the terminal portion; and a flexible printed circuit including a plurality of holes through which the plurality of metal leads penetrate, and wires electrically connected to the metal leads.

Abstract: An optical module includes: an optical receiving module 101 provided with a plurality of leads 105 for transmitting an electrical signal at 15 Gbit/s or more; a printed circuit board 103 provided with a pad 106 that is connected with the plurality of leads 105 by solder; and a metal thin plate 102 that is provided between the printed circuit board 103 and the optical receiving module 101 when the optical receiving module 101 is mounted on the printed circuit board 103. The thickness of the metal thin plate 102 is defined in such a manner that a distance between the plurality of leads 105 and the pad 106 is in the range of 50 to 500 ?m after the optical receiving module. 101 is mounted on the printed circuit board 103.

Abstract: In pattern synchronization for correctly regenerating received data, which is performed in an optical receiver for receiving an optical signal that has been subjected to quadrature phase modulation, signal conduction is quickly established without using duplicate combinations of bit shifting and pattern changing. A control method that does not involve verifying the duplicate combinations generated in modulation formats and pattern synchronization search orders. Specifically, a signal check circuit (40) performs data verification of data multiplexed by a MUX circuit (38) for multiplexing two data strings, and a bit shift pattern change control circuit (41) controls a bit shift circuit (36) and a pattern changing circuit (37) based on a result of the data verification and detects a correct combination of correct regenerated data to establish the signal conduction. At this time, for the bit shift circuit (36) and the pattern changing circuit (37), the duplicate combinations are not verified.

Abstract: A relation between a light input power monitor value of an optical transmission signal before passing through a fiber and an input signal amplitude monitor value is recorded in advance in a storage device. Next, actual optical-transmission-waveform is inputted into an optical receiver module, and then comparisons between a light input power monitor value and an input signal amplitude monitor value, and respective monitor values in the case without having the waveform distortion as described above are performed in an operation device to calculate a waveform distortion value. According to the waveform distortion level calculated herein, an optimum threshold value and an optimum phase adjusting value, at which receiver sensitivity is maximized, are calculated in the operation device to control a threshold-value adjusting circuit and a phase-value adjusting circuit, thereby a threshold value and a phase value that are optimum for an input distortion level can be established.

Abstract: The printed circuit board with the respective components of the optical transmitter-receiver mounted thereon is split into several parts, the fixing position of which respective parts with regard to the housing is set according to the standardized size of the respective components and which respective parts are interconnected through an electric connector and so forth, which makes the height of the transmitter-receiver lower. The split circuit boards are overlapped such that they make no contact with one another so as to enlarge the area of the circuit boards or practically increase the packaging area of the respective components, which realizes the structural compactness of the optical transmitter-receiver. The packaging side of the respective components is selected in an arbitrary manner according to the cooling direction of the respective ICs, which allows such direction to be oriented to the side of the heat sinks so as to enhance cooling behavior.

Abstract: A relation between a light input power monitor value of an optical transmission signal before passing through a fiber and an input signal amplitude monitor value is recorded in advance in a storage device. Next, actual optical-transmission-waveform is inputted into an optical receiver module, and then comparisons between a light input power monitor value and an input signal amplitude monitor value, and respective monitor values in the case without having the waveform distortion as described above are performed in an operation device to calculate a waveform distortion value. According to the waveform distortion level calculated herein, an optimum threshold value and an optimum phase adjusting value, at which receiver sensitivity is maximized, are calculated in the operation device to control a threshold-value adjusting circuit and a phase-value adjusting circuit, thereby a threshold value and a phase value that are optimum for an input distortion level can be established.

Abstract: A connection structure is applied to mutually connect a first and a second transmission line that is planar in shape and that has a ground conductor on a second main surface, such as a microstrip line or a coplanar line with a ground. The first and the second transmission lines are superposed one upon the other, and their signal wiring patterns are electrically connected, as are their ground conductors. An end surface of the first transmission line is substantially covered by a conductor layer connected to the ground conductor. The connection structure can achieve good signal transmission characteristics up to high-frequency bands on the order of several tens of gigahertz.

Abstract: An optical transmission system includes a current source for outputting a drive current, a semiconductor laser for converting the drive current into a stimulated emission light and producing the same, a drive circuit for converting a transmission data signal into a modulation control signal and outputting the same, an optical modulator for receiving the stimulated emission light and a shading control signal for interrupting light emission and producing and outputting transmission signal light by changing an amount of transmission of the stimulated emission light according to the shading control signal, and a shading element for receiving the transmission signal light and a shading control signal for interrupting light emission and interrupting the transmission of the transmission signal light according to the shading control signal whereby an optical signal having wrong optical wavelength is rapidly prevented.

Abstract: A connection structure is applied to mutually connect a first and a second transmission line that is planar in shape and that has a ground conductor on a second main surface, such as a microstrip line or a coplanar line with a ground. The first and the second transmission lines are superposed one upon the other, and their signal wiring patterns are electrically connected, as are their ground conductors. An end surface of the first transmission line is substantially covered by a conductor layer connected to the ground conductor. The connection structure can achieve good signal transmission characteristics up to high-frequency bands on the order of several tens of gigahertz.

Abstract: The printed circuit board with the respective components of the optical transmitter-receiver mounted thereon is split into several parts, the fixing position of which respective parts with regard to the housing is set according to the standardized size of the respective components and which respective parts are interconnected through an electric connector and so forth, which makes the height of the transmitter-receiver lower. The split circuit boards are overlapped such that they make no contact with one another so as to enlarge the area of the circuit boards or practically increase the packaging area of the respective components, which realizes the structural compactness of the optical transmitter-receiver. The packaging side of the respective components is selected in an arbitrary manner according to the cooling direction of the respective ICs, which allows such direction to be oriented to the side of the heat sinks so as to enhance cooling behavior.

Abstract: In the initial state, any wavelength variation of the output signal light with a change of the current injected into the laser is monitored with a wavelength meter, the quantity of wavelength variation is fed back to the wavelength compensation circuit, a compensation voltage for maintaining the wavelength in the initial stage is figured out, and that voltage is recorded into a memory element or the like. A configuration to add this compensation voltage to a comparator makes it possible to compensate for fluctuations of the characteristics of the optical splitter, wavelength filter and light receiving elements and thereby to obtain a stable optical wavelength. By constantly monitoring the injected current applied to the laser when the optical transmitter is in operation and giving a compensation voltage matching the current variation to the comparator, stabilization of the optical wavelength can be realized.

Abstract: Two sets of a high speed differential amplifier and a low speed differential amplifier are prepared, and frequency response speeds of these high speed/low speed differential amplifiers are different from each other. Both an oscillating frequency and a frequency modulation sensitivity of a ring oscillator type voltage-controlled oscillator circuit can be separately set by adding two outputs of these differential amplifiers to each other and by varying the selection ratio of these high speed/low speed differential amplifiers in a linear manner. Thus, the setting ranges for the oscillating frequency and the frequency modulation sensitivity are enlarged. At this time, since a summation of currents flowing through the high speed/low speed differential amplifiers is continuously made constant, the oscillating frequency depending characteristic of the output amplitude of the VCO circuit can be canceled.

Abstract: In the initial state, any wavelength variation of the output signal light with a change of the current injected into the laser is monitored with a wavelength meter, the quantity of wavelength variation is fed back to the wavelength compensation circuit, a compensation voltage for maintaining the wavelength in the initial stage is figured out, and that voltage is recorded into a memory element or the like. A configuration to add this compensation voltage to a comparator makes it possible to compensate for fluctuations of the characteristics of the optical splitter, wavelength filter and light receiving elements and thereby to obtain a stable optical wavelength. By constantly monitoring the injected current applied to the laser when the optical transmitter is in operation and giving a compensation voltage matching the current variation to the comparator, stabilization of the optical wavelength can be realized.

Abstract: An optical transmission system includes a current source for outputting a drive current, a semiconductor laser for converting the drive current into a stimulated emission light and producing the same, a drive circuit for converting a transmission data signal into a modulation control signal and outputting the same, an optical modulator for receiving the stimulated emission light and a shading control signal for interrupting light emission and producing and outputting transmission signal light by changing an amount of transmission of the stimulated emission light according to the shading control signal, and a shading element for receiving the transmission signal light and a shading control signal for interrupting light emission and interrupting the transmission of the transmission signal light according to the shading control signal whereby an optical signal having wrong optical wavelength is rapidly prevented.