Abstract:
A light source device can attain a stable output of a harmonic even when there occurs a change in the ambient temperature or fluctuation in the output power. The light source device is provided with a semiconductor laser source (4), an optical waveguide-type QPM-SHG device (5) for generating a second harmonic from light emitted from the semiconductor laser source (4), a wavelength control means (7) for controlling a wavelength of light emitted from the semiconductor laser source (4), a means for slightly fluctuating wavelength (8) for changing a wavelength of light emitted from the semiconductor laser source (4) and a means for detecting a change in output light power of the optical waveguide-type QPM-SHG device (5) that occurs when a wavelength of light emitted from the semiconductor laser source (4) is changed. In this case, a wavelength of light emitted from the semiconductor laser source (4) is controlled to an optimum wavelength of the optical waveguide-type QPM-SHG device (5) based on a change in output light power of the optical waveguide-type QPM-SHG device (5) that occurs when a wavelength of light emitted from the semiconductor laser source (4) is changed.
Abstract:
An optical information recording/reproducing device reproduces digital data recorded in a form of interference fringes produced by two coherent beams in a hologram disk, by projecting a coherent beam to the hologram disk and receiving a reproduction signal beam obtained by diffraction by means of a two-dimensional photodetector array. The holographic optical information recording/reproducing device includes a tunable coherent light source that emits the coherent beam, and a control section controls and optimizes a wavelength of the tunable coherent light source according to position information of the reproduction signal beam on the two-dimensional photodetector array. Thus, a holographic optical information recording/reproducing device is provided that is capable of maintaining a sufficient reproduction signal intensity and reproducing signals stably while undergoing a minimum of cross-talk, even in the case where the optimal reproduction wavelength varies due to a variance of media, a change of a temperature of a recording medium, etc.
Abstract:
In a hybrid vehicle, power is transmitted via a torque converter provided with a lock-up clutch, and a force input through wheels during deceleration is transmitted to the motor via the torque converter so that a regenerative operation may be carried out by the motor to convert deceleration energy into regenerative energy. The hybrid vehicle includes a throttle opening degree detection unit which detects an opening degree of the throttle; a lock-up clutch engaging state determination unit which determines an engaged state of the lock-up clutch; and a lock-up clutch engagement control unit which controls an engagement of the lock-up clutch. The lock-up clutch engagement control unit, if the throttle opening degree detection unit detects a completely closed state of the throttle, controls the lock-up clutch so as to be engaged regardless of an engaged state of the lock-up clutch determined by the lock-up clutch engaging state determination unit.
Abstract:
A control device for a hybrid vehicle is described which enables preventing a decrease in the efficiency of regeneration even when the revolution rate of an internal combustion engine is decreased during deceleration of the vehicle. The control device for a hybrid vehicle comprises an internal combustion engine and a motor connected in series with respect to each other, a torque converter which is connected to the rotational axis of the motor and which is provided with a lockup clutch, a transmission, a mechanical oil pump producing oil pressure for controllably operating the torque converter and the transmission, a motor-driven oil pump producing oil pressure for controllably operating the lockup clutch, and an ECU. The ECU operates the motor-driven oil pump depending on the deceleration state of the vehicle, and sets the lockup clutch in an engaged state. A method for operating the concerned control device is also described.
Abstract:
A method for forming a ferroelectric domain-inverted structure, having the steps of joining at least two kinds of ferroelectric material which have different spontaneous polarizations, and ferroelectric domain-inverting one of the ferroelectric materials and thereby ferroelectric domain-inverting the other ferroelectric material joined thereto.
Abstract:
A laser beam as fundamental waves which is emitted from a distribution Bragg reflection (DBR) semiconductor laser is incident on an optical waveguide of a light wavelength conversion device in which domain-inverted regions and the optical waveguide are formed in an LiTaO3 substrate. The wavelength of the incident laser beam is then converted so as to obtain higher harmonic waves such as blue light. In the conversion, a drive current to be applied to a DBR portion of the DBR semiconductor laser is changed so as to change an oscillating wavelength of the DBR semiconductor laser, thereby matching the oscillating wavelength with a phase-matched wavelength of the light wavelength conversion device. Thus, the generation of the harmonic waves to be output is stably controlled.
Abstract:
An optical waveguide device includes a dielectric substrate; and an optical waveguide formed in the dielectric substrate, the optical waveguide having a longitudinal axis and an outgoing surface disposed at an angle other than a right angle relative to a plane perpendicular to the longitudinal axis.
Abstract:
A wavelength-variable semiconductor laser includes: a submount; and a semiconductor laser chip being mounted onto the submount and having at least an active layer region and a distributed Bragg reflection region, wherein the semiconductor laser chip is mounted onto the submount in such a manner that an epitaxial growth surface thereof faces the submount and a heat transfer condition of the active layer region is different from a heat transfer condition of the distributed Bragg reflection region. Moreover, an optical integrated device includes at least a semiconductor laser and an optical waveguide device both mounted on a submount, wherein the semiconductor laser is the wavelength-variable semiconductor laser as set forth above.
Abstract:
A system for controlling motive force of a vehicle having an engine and an automatic transmission connected to the engine to transmit engine torque to a drive shaft of the vehicle, wherein a control mode is selected from among a plurality of predetermined control modes in response to a calculated desired motive force and vehicle speed such that the fuel economy is enhanced and engine torque and speed (gear) ratio are controlled in response thereto. Moreover, the desired motive force is calculated by obtaining a difference between the wide-open-throttle motive force and the full-closed-throttle motive force and by multiplying the difference by a calculated ratio of motive force. Furthermore, the calculated desired output of the engine and the desired gear ratio are controlled such that the desired motive force is generated when the desired motive force is discriminated to be achievable. Thus, the engine and the automatic transmission are controlled in conjunction and the desired motive force is appropriately obtained. The speed (gear) ratio is changed to effect the desired motive force. With the arrangement, fuel economy and emission performance are enhanced.
Abstract:
A light generating apparatus includes: a submount; a semiconductor laser chip mounted on the submount; a substrate which is mount on the submount and includes an optical waveguide; and a substance having a predetermined thickness which is disposed between the semiconductor laser chip and the substrate. In an oscillation wavelength stabilizing apparatus for a light source, the light source is a semiconductor laser which includes: an active region for providing gain; and a distributed Bragg reflection (DBR) region for controlling an oscillation wavelength. The apparatus includes a control section which monotonously varies, in a first direction, a DBR current to be input to the DBR region while detecting the oscillation wavelength of an output light of the semiconductor laser so as to detect a DBR current value I.sub.o corresponding to a predetermined wave-length value, and then monotonously varies the DBR current in a second direction which is opposite the first direction beyond the detected value I.sub.o and then monotonously varies the DBR current in the first direction again to set the DBR current at the detected value I.sub.o, thereby fixing the oscillation wavelength of the semiconductor laser chip at the predetermined wavelength value.