摘要:
There is provided herewith an apparatus, probe, and method for the combination of near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS). The apparatus, probe and method allow for the simultaneous detection of NIRS and DCS.
摘要:
There is provided herewith an apparatus, probe, and method for the combination of near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS). The apparatus, probe and method allow for the simultaneous detection of NIRS and DCS.
摘要:
An object of the present invention is to provide an optical measuring device and optical measuring method capable of locally irradiating a measuring object with light and efficiently receiving reflection, scattered light, fluorescence, etc. from the measuring object.An optical measuring device according to the present invention has a light emitting portion; an irradiation waveguide for guiding light from the light emitting portion toward an object; a receiving waveguide for guiding light from the object; and a light receiving portion for receiving the light having been guided through the receiving waveguide; and is characterized in that a numerical aperture at a receiving end of the receiving waveguide is larger than a numerical aperture at an emission end of the irradiation waveguide.
摘要:
An optical line monitoring apparatus and optical line monitoring system which can measure a reflectance distribution in an optical line with a high spatial resolution in a short time are provided. An optical line monitoring apparatus 14A provided in a station 10A comprises an OCDR measurement section 15 for carrying out OCDR measurement, an OTDR measurement section 16 for carrying out OTDR measurement, an optical switch 13 for selectively connecting one of the OCDR measurement section 15 and OTDR measurement section 16 to the optical coupler 12, a control section 17, and a storage device 18. The control section 17 performs a predetermined arithmetic operation according to an OCDR measurement result acquired by causing the OCDR measurement section 15 to carry out the OCDR measurement and an OTDR measurement result acquired by causing the OTDR measurement section 16 to carry out the OTDR measurement.
摘要:
The present invention relates to an optical amplifier with a structure for more effectively suppressing the over/undershoot in transient responses in high-speed AGC. This optical amplifier is an optical device for amplifying signal light inputted therein, and comprises a rare-earth-element-doped optical fiber, an optical coupler, a light-receiving section, a pumping light source, and a control section. In particular, as a typical structure of the optical amplifier, the rare-earth-element-doped optical fiber has a cutoff wavelength λc set longer than the pumping light wavelength λp but shorter than the signal light wavelength λs, and mainly allows a pumping light component in a fundamental mode to propagate therethrough. The pumping light and signal light are made incident on the first rare-earth-element-doped optical fiber such that only the pumping light component in the fundamental mode and a signal light component in the fundamental mode propagate through the first rare-earth-element-doped optical fiber in a state where the first rare-earth-element-doped optical fiber extends straight.
摘要:
A Raman amplifier can easily reduce the gain variation in Raman amplification even when the power of an input signal varies. The Raman amplifier is provided with (a) an optical fiber that Amplifies an input lightwave to produce an output lightwave, (b) a pump-lightwave-supplying means that supplies pump lightwaves having a plurality of wavelengths to the optical fiber, and (c) a control unit that controls only the power of the pump lightwave having the shortest wavelength among the pump lightwaves so that the average value of the gain of the Raman amplification by the optical fiber in an intended wavelength range can be maintained constant.
摘要:
The invention relates to an optical amplifier capable of achieving high-speed gain control in a wide dynamic range with a simpler constitution. A gain control circuit of the optical amplifier includes a first photodetector for outputting a voltage having a linear relation with power of part of signal light to be inputted to the optical amplifier medium, a second photodetector for outputting a voltage having a linear relation with power of part of the signal light amplified in the optical amplifier medium, a comparator for outputting a difference between the voltages respectively outputted from the first and second photodetectors, and a drive circuit for supplying a desired drive current to a pumping light source in response to the voltage outputted from the comparator. Each of the first and second photodetectors includes a photoelectric conversion element for performing conversion into an electric current in response to inputted optical power, and an operational amplifier for converting the electric current outputted from the photoelectric conversion element into a voltage. Particularly, at least one of the first and second photodetectors includes an adjusting mechanism for adjusting an offset of the outputted voltage.
摘要:
A Raman amplifier can easily reduce the gain variation in Raman amplification even when the power of an input signal varies. The Raman amplifier is provided with (a) an optical fiber that Amplifies an input lightwave to produce an output lightwave, (b) a pump-lightwave-supplying means that supplies pump lightwaves having a plurality of wavelengths to the optical fiber, and (c) a control unit that controls only the power of the pump lightwave having the shortest wavelength among the pump lightwaves so that the average value of the gain of the Raman amplification by the optical fiber in an intended wavelength range can be maintained constant.
摘要:
The present invention relates to an optical amplifier comprising a structure which prevents transmission quality from lowering and enables constant gain control with a higher speed and higher accuracy. In a typical embodiment of the present invention, amplified light from an EDF is once guided to an optical filter by way of an optical circulator. Of thus guided amplified light, noise light passes through the optical filter, whereas each of signal components is reflected thereby, so as to separate the noise light and signal components from each other. The noise light having passed through the optical filter is detected by a photodetector, and gain control is carried out by a gain control circuit so as to suppress fluctuations in the detected noise light power.
摘要:
An optical tomography device 1 is provided as one capable of obtaining tomographic information of a measuring object with higher accuracy. In the optical tomography device 1, numerical apertures of reception fibers 12, 13 are different from each other. Therefore, the device has a configuration wherein the reception fibers 12, 13 receive two kinds of respective light beams with different solid angle distributions, whereby the device can also obtain angular information, in addition to intensity information of light emerging from a measuring object 100. As a result, the accuracy is enhanced for an analysis about the tomographic information of the measuring object.