摘要:
The integrated optical control element of this invention includes: a first waveguide for allowing light incident from outside to propagate therein; a multilayer structure for allowing the light which has propagated in the first waveguide to be incident thereon and for transmitting the light therethrough or reflecting the light therefrom, the multilayer structure including at least one layer having a refractive index different from an equivalent refractive index of a region with which the at least one layer is in contact; and a second waveguide for receiving at least part of the light transmitted through or reflected from the multilayer structure.
摘要:
A spatial coherent light transmission apparatus according to the present invention, includes: a light transmitter for emitting a data signal as first coherent light; a light receiver for emitting second coherent light having a wavelength little different from that of The first coherent light, mixing and receiving the first and second coherent lights, and performing a coherent detection of the data signal. At least one of the light transmitter and the light receiver has a detection device for detecting at least one of a coherent light transmission state and a coherent light detection state. The apparatus further includes a control device for controlling at least one of the light transmitter and the light receiver based on information of the state detected by the detection device.
摘要:
The integrated optical control element of this invention includes: a first waveguide for allowing light incident from outside to propagate therein; a multilayer structure for allowing the light which has propagated in the first waveguide to be incident thereon and for transmitting the light therethrough or reflecting the light therefrom, the multilayer structure including at least one layer having a refractive index different from an equivalent refractive index of a region with which the at least one layer is in contact; and a second waveguide for receiving at least part of the light transmitted through or reflected from the multilayer structure.
摘要:
An optical heterodyne detection method of detecting a beat signal by heterodyne detection using a superimposition of two or more beams of light including a signal beam and a reference beam, includes the steps of: generating a scattered reference beam from the reference beam: and detecting the beat signal obtained from the scattered reference beam and the signal beam, by superimposing the scattered reference beam and the signal beam.
摘要:
A system for transmitting information with a coherent beam being propagatable in the air is arranged to include a transmitting device having a modulator and an emitting circuit and a receiving device having a generator, a mixer, a frequency discriminating circuit, and reproducing circuit. The modulator modulates a reference light frequency (wavelength) or phase of a coherent beam to be emitted from a light source according to the signal. The emitting circuit emits the modulated beam as a divergent beam having such a power density as being safe to human eyes. The generator generates a coherent locally oscillated beam. The mixer mixes the signal beam with the locally oscillated beam and photoelectric-converts the mixed beam. The frequency discriminating circuit frequency-discriminates the a.c. component of the photoelectric-converted output. The reproducing circuit reproduces a signal from the output of frequency discriminating circuit. Any one of the transmitting device and the receiving device has a function of keeping a relative light frequency difference (wavelength difference) between the signal beam and the locally oscillated beam constant.
摘要:
An optical data reading method and apparatus for photoelectrically converting reflection light of a laser beam radiated onto a recording medium and thereby reproducing digital data recorded in the recording medium, performing a coherent detection by photoelectrically converting a first laser beam having a light frequency .nu..sub.1 and a second laser beam having a light frequency .nu..sub.2, where .nu..sub.1 -.nu..sub.2 .gtoreq.R (R: rate of reading the digital data), in a state where wavefronts of the first and second laser beams are aligned with each other, detecting temporal changes of either an amplitude or a phase of a beat signal component of the first and second laser beams, having a frequency of (.nu..sub.1 -.nu..sub.2) and being included in an photoelectrically converted output, and reading the digital data recorded in the recording medium based on a result of detection.
摘要:
A spatial optical transmission apparatus includes: a light signal transmitting device for generating a signal beam which is modulated in accordance with a signal to be transmitted and is intensity-modulated with a lower frequency compared with a signal transmission speed; and a light signal demodulating device for receiving the signal beam from the light signal transmitting device by a detector, adjusting the direction of a locally oscillated beam based on the received signal beam so as to have a predetermined relationship with the direction of the signal beam so that intensity-modulated components in an output signal from the detector falls within a predetermined range of intensity, thereby aligning the wavefront of the signal beam with the wavefront of the locally oscillated beam, and extracting signal components which correspond to the transmitted signal from signal components modulated in accordance with the transmitted signal in the signal beam.
摘要:
In an assembly structure of an optical integrated circuit device for assembling a semiconductor laser device and an optical integrated circuit substrate, the semiconductor laser device includes a recessed/raised structure. On the other hand, the optical integrated circuit substrate includes another recessed/raised structure to fit the recessed/raised structure of the semiconductor laser device. These recessed/raised structures are formed so that their cross sections taken parallel to the layers forming the semiconductor laser device are symmetric in shape about the respective optical axes of the semiconductor laser device and the optical integrated circuit substrate. Further, the recessed/raised structures preferably contain a tapered portion as part of its contour, the taper forming a prescribed angle with the respective optical axes. Thus, the mounting accuracy required to achieve the prescribed coupling efficiency in the optical integrated circuit device can be obtained by simple mechanical operations.
摘要:
A method for optically reading recorded information by radiating laser light emitted from a semiconductor laser which oscillates in a single longitudinal mode to an information recording medium and by detecting laser light reflected from a recording face of the information recording medium is disclosed. In the method, the optical frequency of the laser light is modulated in order that the modulated optical frequency is a periodic function dependent on time, and the absolute value of a time differential coefficient R (Hz/s) of the periodic function, a spectral line width .delta. .nu. (Hz) of the laser light, and a time period .tau. (s) from the time when the laser light is emitted to the time when the laser light reflected from the recording face of the information recording medium reaches the semiconductor laser satisfy the condition of R.gtoreq..delta. .nu./.tau.. The periodic function varies to have a sawtooth waveform or a triangular waveform.
摘要:
A light-emitting apparatus composed of a light source that emits primary light and a phosphor that absorbs the primary light and emits secondary light offers high brightness, low power consumption, and a long lifetime while minimizing adverse effects on the environment. The phosphor is formed of a III-V group semiconductor in the form of fine-particle crystals each having a volume of 2 800 nm3 or less. The light emitted from the fine-particle crystals depends on their volume, and therefore giving the fine-particle crystals a predetermined volume distribution makes it possible to adjust the wavelength range of the secondary light.