Abstract: A reduced size ceramic block filter has trap holes whose center is askew from the line running through the center of the transmission poles such that the height-wise distance between its center and the center line of the transmission poles is greater than (dt+d1)/2, but not greater than 3/8 of the height of the filter. The trap hole is also width-wise spaced from the next nearest transmission hole by an amount which approximates the distance between transmission holes. Due to this layout the diameter of the trap holes are reduced in order to maintain performance which is equivalent to a conventional filter whose trap holes are timely aligned with its transmission poles. The combination of reduced trap hole diameter and reduced width-wise spacing between traps and transmission holes, results in a reduced size ceramic filter.

Abstract: An object of this invention is to improve coupling efficiency of a silica optical waveguide having a high relative refractive index difference and a single mode optical fiber. A silica optical waveguide (10) consists of a single mode optical waveguide, and its core (12) is originally a rectangle. A width of the core (12) of the silica optical waveguide (10) is tapered at a predetermined length part (16) connecting to an optical fiber (20). A thickness of the core (12) in the tapered part (16) is constant.

Abstract: A transmission band filter (110) having a series of elements (111, 113, 115) each composed of a film bulk acoustic resonator and grounded shunt elements (112, 114) each composed of a film bulk acoustic resonator is connected between a transmission port (102) and an antenna port (106). A reception band filter (130) having a series of elements (131, 133, 135) each composed of a film bulk acoustic resonator and grounded shunt elements (132, 134, 136) each composed of a film bulk acoustic resonator is connected between a reception port (104) and the antenna port (106). A film bulk acoustic resonator (150) for adjustment is connected between the antenna port (106) and the ground. The resonance frequency of the adjusting film bulk acoustic resonator (150) lies between the upper limit frequency of the transmission frequency pass band of the transmission band filter (110) and the lower limit frequency of the reception frequency pass band of the reception band filter (130).

Abstract: A band-pass filter has a ladder-type circuit including first and second terminals whose characteristic impedances are Z0, and series elements and shunt elements disposed between a first terminal and a second terminal, each of the series elements and shunt elements containing a film bulk acoustic resonator. Assuming that characteristic impedance of any one of the series elements is Z1 and that characteristic impedance of any one of the shunt elements is Z2, the characteristic impedances Z0, Z1, and Z2 have a relation of 1<(Z1/Z0)<2, preferably 1.3<(Z1/Z0)<1.7, and 0.5<(Z2/Z0)<1, preferably 0.6<(Z2/Z0)<0.8.

Abstract: An optical circulator outputs an optical signal entered through its port A from its port B. A fiber collimator makes the optical signal spread out from the port B of the optical circulator into a collimated beam and applies it to a beam splitter. The beam splitter is disposed at an angle of 45° to the optical axis. Around of the beam splitter, total reflection mirrors are disposed in three directions per angle of 90° except for the direction in which the fiber collimator is disposed. The distance between the total reflection mirrors and the beam splitter is adjustable.

Abstract: An optical gate according to the invention comprises a polarization divider to divide an optical signal into two orthogonal polarization components and to output them as a first polarization component which precedes in the time base and a second polarization component which follows the first one in the time base; a semiconductor optical amplifier to modulate the phase of the second polarization component output from the polarization divider according to a control light; an assist light supplier to supply to the semiconductor optical amplifier an assist light to help the recovery of the refractive index variation of the semiconductor optical amplifier caused by the control light; a polarization combiner to combine the first and second polarization components of the optical signal transmitting on the semiconductor optical amplifier so as to adjust them in the same time location; and a polarization extractor to extract a predetermined polarization direction component from the output from the polarization combine

Abstract: A filter with an equivalent circuit that functions as well as physically larger filters without substantial drop off in performance.

Abstract: An optical delay unit comprises a periodic wavelength demultiplexer having M (M is a natural number) input ports including a signal input port, M output ports including a signal output port, and periodic input/output characteristics for wavelengths between the M input ports and the M output ports, and (M−1) optical paths to connect each of the (M−1) output ports in which the signal output port is excluded from the M output ports of the periodic wavelength demultiplexer with any of the (M−1) input ports in which the signal input port is excluded from the M input ports of the periodic wavelength demultiplexer.

Abstract: A reduced size ceramic block filter has trap holes whose center is askew from the line running through the center of the transmission poles such that the height-wise distance between its center and the center line of the transmission poles is approximately between {fraction (1/8 )}and {fraction (3/8 )}of the height of the filter. The trap hole is also width-wise spaced from the next nearest transmission hole by an amount which approximates the distance between transmission holes. Due to this layout the diameter of the trap holes are reduced in order to maintain performance which is equivalent to a conventional filter whose trap holes are timely aligned with its transmission poles. The combination of reduced trap hole diameter and reduced width-wise spacing between traps and transmission holes, results in a reduced size ceramic filter.

Abstract: An object of this invention is to improve coupling efficiency of a silica optical waveguide having a high relative refractive index difference and a single mode optical fiber. A silica optical waveguide (10) consists of a single mode optical waveguide, and its core (12) is originally a rectangle. A width of the core (12) of the silica optical waveguide (10) is tapered at a predetermined length part (16) connecting to an optical fiber (20). A thickness of the core (12) in the tapered part (16) is constant.

Abstract: An object of this invention is to compensate group delay or group velocity dispersion. An optical circulator (12) outputs an optical signal (10) entered through its port A from its port B. A fiber collimator (14) makes the optical signal spread out from the port B of the optical circulator (12) into a collimated beam and applies it to a beam splitter (16). The beam splitter (16) is disposed at an angle of 45° to the optical axis. Around of the beam splitter (16), total reflection mirrors (18, 20, and 22) are disposed in three directions per angle of 90° except for the direction in which the fiber collimator (14) is disposed. The distance between the total reflection mirrors (18, 20, and 22) and the beam splitter (16) is adjustable.

Abstract: A ceramic block filter is designed with a shunt transmission line to attenuate third harmonics. A metallized belt is printed on the top surface of the filter along its edges so that it is connected to the metallized ground of the side surfaces. Along one edge an unmetallized line is left along one edge of the filter, whose ends are grounded. The unmetallized line is designed with a length greater than one-half of the length of the metallized belt, but smaller than the length of the metallized belt. The length and width of the unmetallized line are design choices for the specific frequencies sought to be attenuated.

Abstract: An optical signal processor is disclosed comprising a first optical path having a first electroabsorption optical modulator to be applied with a constant voltage and to absorb light of a signal wavelength, a second optical path having a fixed phase relation with the first optical path relative to a probe wavelength, a probe light introducer for dividing probe light of the probe wavelength into two portions and feeding them respectively into the first and second optical paths, an original signal light introducer for introducing original signal light of the signal wavelength into the first electroabsorption optical modulator, and a combiner for combining both light of the probe wavelength passed through the first and second paths.

Abstract: An optical gate according to the invention comprises a polarization divider to divide an optical signal into two orthogonal polarization components and to output them as a first polarization component which precedes in the time base and a second polarization component which follows the first one in the time base; a semiconductor optical amplifier to modulate the phase of the second polarization component output from the polarization divider according to a control light; an assist light supplier to supply to the semiconductor optical amplifier an assist light to help the recovery of the refractive index variation of the semiconductor optical amplifier caused by the control light; a polarization combiner to combine the first and second polarization components of the optical signal transmitting on the semiconductor optical amplifier so as to adjust them in the same time location; and a polarization extractor to extract a predetermined polarization direction component from the output from the polarization combine

Abstract: A high performance dielectric ceramic filter in a small package is designed with one or more holes positioned off of the straight-line bisecting at least two holes. This configuration allows for the elimination of at least one trap hole while maintaining a given performance characteristic for the filter. In one specific embodiment of the present invention the performance characteristics of a conventional five-hole ceramic filter is realized in a three-hole filter wherein the holes are positioned so as to form the vertices of a triangle. The width of the resulting filter is approximately 50% of the width of the conventional five-hole filter it can replace. In another embodiment the same triangular positioning may be used to realize the performance characteristics of a four-hole ceramic filter.

Abstract: A nonlinear optical element is disclosed for reducing intensity noise of both mark level and space level, and being stable, miniaturized and low-priced. Signal light enters a semiconductor waveguide layer (14). The semiconductor waveguide layer (14) has a band gap wavelength shorter than a wavelength of the signal light. A diffraction grating (12), having a Bragg wavelength close to the wavelength of the signal light, is disposed adjacent to the semiconductor waveguide layer (14). DC voltage is applied to the semiconductor waveguide layer (14).

Abstract: An electronic apparatus includes power source for supplying a power, key input unit for inputting key instructions, a memory for memorizing the key instructions, a generator for generating a power off cancel instruction to be invalidated the power-off of the power supplied from the power source in response to at least one of the key instructions or at least one of the memorized instructions memorized by the memory, a detector for detecting the output of the power off cancel instruction generator, and a controller for controlling the power source in response to the output of the detector.

Abstract: In a language translator with a speech synthesizer, fixed words and variable words messages with translation are selectable.

Abstract: An electronic apparatus includes power source for supplying power, a key input unit for inputting key instructions, a memory for memorizing the key instructions, a generator for generating a power off cancel instruction to be invalidated the power-off of the power supplied from the power source in response to at least one of the key instructions or at least one of the memorized instructions memorized by the memory, a detector for detecting the output of the power off cancel instruction generator, and a controller for controlling the power source in response to the output of the detector.

Abstract: An asset control device comprising an input keyboard for entering information of transactions including the amount of a check and that of deposit, a current balance storage, an opening balance storage, a transaction storage for registering the serial number of a check and the amount thereof each time the check is drawn or the amount of money deposited each time the deposit of money is effected, a calculator operable to subtract the amount of check stored in the transaction storage from the opening balance or to add the amount of the deposited money stored in the transaction storage to the opening balance, and a display unit for sequentially displaying the transaction information and the result of calculation performed by the calculator.