Abstract: A monochromator including: a concave mirror which converts incident light into parallel light and emits the parallel light, a plane diffraction grating for diffracting the parallel light emitted from the concave mirror, first reflection means which reflects first light diffracted by the plane diffraction grating and causes the diffracted light to enter the plane diffraction grating as second incident light, second reflection means which reflects second diffracted light and causes the reflected light to enter the plane diffraction grating as third incident light, and an exit slit disposed in the vicinity of a focal point such that third diffracted light is reflected by the first reflection means, to thereby enter the plane diffraction grating as fourth incident light and such that fourth diffracted light is converged at the focal point by the concave mirror, to thereby enable extraction of light having a specific wavelength.

Abstract: In order to start sweeping an optical spectrum analyzer 1 and a wavelength tunable light source 14 on the same timing, a motor 6 for driving a spectroscope 4 in the optical spectrum analyzer 1 is controlled. To this end, a drive circuit 7 outputs a control signal to determine the timing where the motor 6 starts to rotate. A wavelength control circuit 19 in the wavelength tunable light source 14 controls the sweep of the wavelength of single-mode oscillation from a light source unit 20 and starts sweeping the light source unit 20 in response to a signal externally supplied to control the timing of sweep start. As a result, the sweep of the wavelength being measured with the optical spectrum analyzer 1 and that of the wavelength of single-mode oscillation from the wavelength tunable light source 14 are started on the same timing and high-speed sweep is achieved.

Abstract: In an optical amplifier evaluation instrument, a rectangular spectrum light source 1 transmits continuous light having a wide-band and flat spectrum shape, a first optical modulator 2 receives and pulse-modulates the continuous light. Further, a second optical modulator 3 operates in the same period as the first optical modulator 2 and performs the on/off pulse operation, thereby providing a sampling window in a time domain for extracting and suppressing an optical signal. A modulation signal generation section 4 performs such control and drive. An optical signal undergoing pulse intensity modulation is input to a measured optical amplifier 6. Post-amplified signal light power for each frequency component and amplified spontaneous emission power for each frequency component in a time domain in which no optical pulse signal exists are measured and operations are performed for each wavelength.

Abstract: Emitted light from a light source 1 is separated into two parts through an optical fiber coupler 2, one is entered in a measured optical module 3 as measurement light, and the other is given a group delay by means of an optical fiber delay line 5, a reflector 25, etc., as local light signal, then the local light signal is combined with reflected light signal from the measured optical module 3 through an optical fiber coupler 21 and the reflected light signal and the local light signal are caused to interfere with each other. A polarization controller 100 comprising a polarizer and a polarization rotation device for arbitrarily rotating the polarization state 0 degrees and 90 degrees at the time is used to generate beat signals at the polarization rotation angles, and the sum of the intensities of the beat signals is found, making it possible to measure the light power of the reflected light signal regardless of the polarization state of the local light signal or reflected light signal.

Abstract: A photocoupler 3 splits the light from a low-coherence light source 1 into measuring light DL and local oscillator light KL. A photocoupler 5 receives measuring light DL arid is input to an optical circuit 7 to be measured. The photocoupler 5 splits the reflected light RL. A polarization controller 9 controls the state of polarization of the reflected light RL as split by the photocoupler 5. A photocoupler 13 allows local oscillator light KL to be incident on a reflector mirror 16 and splits local oscillator light KL. A photocoupler 11 combines the reflected light RL as controlled in the state of polarization by the polarization controller 9, with the local oscillator light KL.

Abstract: Output light spectrum P2(&lgr;) data from an optical amplifier and input light spectrum P1(&lgr;) data of signal light are prepared, the difference between the P2(&lgr;) and a value obtained by multiplying the P1(&lgr;) by a provisional gain GT is determined (Steps S232), for the obtained spectrum data, a noise removing process such as a moving average process and the like is performed and then, a spline interpolation process is also performed, whereby ASE light spectrum P3(&lgr;) data is prepared and an ASE light level P ASE is determined (Steps S233 through S235). In addition, a noise figure-measuring device 10 calculates the number of channels of WDM light and signal light wavelengths of the respective channels based on the P1(&lgr;) or P2(&lgr;), and performs analysis to calculate a noise figure NF and the like of an appointed wavelength range around the center of each wavelength thus calculated.

Abstract: In an optical amplifier evaluation instrument, a rectangular spectrum light source 1 transmits continuous light having a wide-band and flat spectrum shape, a first optical modulator 2 receives and pulse-modulates the continuous light. Further, a second optical modulator 3 operates in the same period as the first optical modulator 2 and performs the on/off pulse operation, thereby providing a sampling window in a time domain for extracting and suppressing an optical signal. A modulation signal generation section 4 performs such control and drive. An optical signal undergoing pulse intensity modulation is input to a measured optical amplifier 6. Post-amplified signal light power for each frequency component and amplified spontaneous emission power for each frequency component in a time domain in which no optical pulse signal exists are measured and operations are performed for each wavelength.

Abstract: The present invention relates to a double pass monochromator that improves wavelength resolution and reduces the actual length thereof. A return reflection means 7 that reverses the direction of dispersion of the wavelength of the second pass light 1c, 1f emitted and incident on a diffraction grating 4 during the reflection. In addition, the angles of the incident and emitted light during separation of spectral components by the diffraction grating are identical during the first and second diffraction.

Abstract: An optoacoustic modulator contains first and second optoacoustic media, to which first and second piezoelectric vibrators are attached respectively. Herein, both of the first and second optoacoustic media are designed in same measurements, wherein they are arranged in series along an optical axis of a light signal in such a way that crystal orientation of the first optoacoustic media differs from crystal orientation of the second optoacoustic media with an angle of inclination of 90.degree.. In addition, the first piezoelectric vibrator is attached to a first surface of the first optoacoustic media which is placed in parallel with the optical axis of the light signal, while the second piezoelectric vibrator is attached to a second surface of the second optoacoustic media which is placed in parallel with the optical axis of the light signal, wherein the first surface is directed perpendicular to the second surface.

Abstract: A distance correction method and the controller for a reflectometer is disclosed which is able to perform accurate correction of the distances measured by reflectometer. In the distance correction method for the reflectometer which measures the Fresnel reflection or Raleigh back-scattering light of an optical fiber or an optical waveguide, the distance correction D.sub.wg1 -D.sub.wgn is performed according to the respective group refraction ratios which are the parameters of the optical fiber or the optical waveguides longitudinally connected with having different known group refraction ratios.

Abstract: An optical amplifier evaluating device has a wavelength multiplex signal light generating section, and an O/E converter, and a frequency discriminating and power detecting device, and a computing section. The wavelength multiplex signal light generating section generates an wavelength multiplex signal light which includes signal lights having different wavelengths and having intensity envelopes modulated by different modulation frequencies which are enough higher than an atom life time in a high energy level or a carrier life time in an amplification medium of an optical amplifier to be evaluated, and supplies the wavelength multiplex signal light to the optical amplifier. The O/E converter converts an output light of the optical amplifier to an electric signal.

Abstract: This invention relates to a transaction processing system including a host computer (1), a transaction device (2), a first customer card (3) and a second customer card (4). The first card (3) and the second card (4) directly transfer information representing monetary values between them on the basis of signals verifying a transaction processing received from the host computer (1) through the transaction device (2). When the information representing the monetary values are exchanged between the first card (3) and the second card (4), the host computer (1) updates the balance of the account stored in the host computer (1).

Abstract: A rear projection type image display apparatus having an arrangement that a projection distance of a projection lens thereof is shortened and a density of mounting of parts relating to an optical system and an electric system is made higher. Furthermore, a width of a rear portion of a housing of the rear projection type image display apparatus is reduced rearwards at any position from the upper portion to the lower portion thereof, and the lower portion of a back cover is depressed inwards. Thus, a space required to install the rear projection type image display apparatus can be reduced, the rear surface of the apparatus can be disposed on a wall without any gap when the apparatus is installed along the wall, and the overall body of the apparatus can be received deep into a corner of walls when the apparatus is installed at the corner.

Abstract: A method and device for automatically and accurately measuring a noise figure of an optical amplifier are disclosed. In the method, light pulses which have different wavelengths .lambda..sub.1 .about..lambda..sub.n and have a period shorter than a time constant of extinction of the optical amplifier are generated. The light pulses thus generate are supplied to the optical amplifier. Powers P.sub.AMP1 .about.P.sub.AMPn of amplified lights outputted from the optical amplifier which correspond to the light pulses and have the wavelength .lambda..sub.1 .about..lambda..sub.n and powers P.sub.ASE1 .about.P.sub.ASEn of lights which have the wavelength .lambda..sub.1 .about..lambda..sub.n and are outputted from the optical amplifier when the amplified lights are not outputted from the optical amplifier are measured. Noise figures NF.sub.1 .about.NF.sub.n at the wavelengths .lambda..sub.1 .about..lambda..sub.n the optical amplifier are calculated according to the following equation.NF.sub.k =(P.sub.ASEk /h.nu..sub.

Abstract: A data processing network in which a plurality of workstations such as personal computers (PC) (12) are connected to a host processor (11) and contain PC programs at particular levels for controlling tasks on the personal computers. The personal computers send a signal to the host when they are about to conduct a task indicating which data files they have and at what level. The host has an object library containing a copy of each disk file for each version of PC program. The host determines if the personal computer has the latest level data file for the version of program at that personal computer and, if it does not, sends a copy of the latest level data file to the personal computer to replace the down-level data file. Preferably, the host checks if the personal computer has all the data files it needs for the particular task and, if it does not and if it should because of the version of PC program stored at the PC, the host can load a copy of the missing file to the personal computer.

Abstract: An area fill technique for graphic images is disclosed wherein the contour lines constituting an image are given in a series of line segments or a series of vectors, and horizontal line segments are ignored. Each line segment other than the horizontal ones is specified by the coordinate addresses for the start and end points in one direction, that is, from top to bottom or from bottom to top. Each is then converted into approximate pixels in the X-Y coordinate system, and stored in a random access work memory. The pixels of each line segment are stored in the work memory according to a rule whereby each line segment is represented by one pixel per horizontal line, and is written by taking exclusive OR of its pixels, excluding the start point, with read pixel data at corresponding coordinate addresses in the work memory.

Abstract: In a planar loudspeaker structure comprising planar membrane for forming a diaphragm on which a voice coil of a conductor pattern is formed, and a magnetic circuit for supplying a DC magnetic flux which crosses the voice coil, the conductor pattern includes first and second zigzag conductor pattern portions which are juxtaposed on substantially the entire area of the membrane and connected in series. Opposite ends of the series connection of the first and second conductor pattern portions are respectively connected to first and second terminals for receiving a low-band component of an input audio signal. A high-band component of the input signal is applied to a third terminal connected to a junction between the first and second conductor pattern portions and supplied only to the second conductor pattern portion.

Abstract: An image-receiving sheet for a heat transfer recording system. The sheet comprises a substrate coated with an image-receiving layer comprised mainly of non-plate-shaped inorganic pigment and a binder. The smoothness of the image-receiving surface as determined according to TAPPI Standard T479 om-81 is 200 to 1,000 sec/10 ml, and the air permeability of the image-receiving sheet, as determined according to ASTM D726 Method B is below 500 sec/100 ml.

Abstract: An immobilized enzyme column useful for automatic chemical analyzers for analyzing substances contained in the blood serum, urine or the like with use of an enzyme for clinical tests includes at least one column main body (19, 34 or 44, 51 and 52). The column has a channel (31) extending from a sample inlet (24) to a sample outlet (27). An air bubble inlet (28) is disposed close to the sample outlet to communicate with the channel (31), and an air bubble outlet (25) is disposed close to the sample inlet to communicate with the channel. An immobilized enzyme accommodating portion (20 or 35) is provided in the channel between the bubble inlet (28) and the bubble outlet (25) and partitioned by a filter (29) at each end thereof.