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公开(公告)号：JPH04145412A
公开(公告)日：1992-05-19
申请号：JP26863090
申请日：1990-10-05
Applicant: AGENCY IND SCIENCE TECHN
Inventor： HIDAKA TATSUHIKO
Abstract: PURPOSE:To transform wide parallel incident rays of light into an extremely sharp needle-like light beam and to maintain the light beam in the same shape for a long distance by providing a 1st optical element which forms an annular image at a prescribed distance and a 2nd optical element which produces non- diffracted light upon receiving the light emitted from the 1st optical element. CONSTITUTION:The L1 in the figure represents a convex lens having an aperture of D/2, focal distance of (f), and special shape formed by rotating the lens 360 deg. around its outer edge section and the L2 represents another convex lens having an ordinary shape. The B represents non-diffracted light produced by these lenses. The parallel rays of light made incident to the lens L1 are condensed to an annular shape having a diameter of D/2 at the position (e) and (e'') of the focal distance (f). Namely, an annular light source which is equivalent to that obtained when an annular slit is used can be formed and the energy efficiency of the lens L1 comes to 100%. Therefore, non-diffracted light can be produced efficiently with the lenses.
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公开(公告)号：JPH0224639A
公开(公告)日：1990-01-26
申请号：JP17439588
申请日：1988-07-13
Applicant: AGENCY IND SCIENCE TECHN
Inventor： HIDAKA TATSUHIKO
IPC: G02F3/00
Abstract: PURPOSE:To reduce the size of the optical arithmetic unit by constituting an optical logical arithmetic operation element by using a medium which has nonlinear characteristics so that light signals of many wavelengths are processed simultaneously and independently. CONSTITUTION:The oscillation light of a laser oscillator 11 which has wavelengths lambda1-lambdan is split into two by a collimator 12, a beam splitter 13a, and a mirror 13b. The light 1 which passes through diffraction grating spectral circuits 14a and 14b is diffracted spectrally and focused at the positions of optical switches 15a and 15b. Electric control signals d1a, d2a... d1b, d2b... which turn on and off the optical switches 15a and 15b are made to correspond to the wavelengths lambda1 and lambda2. The light beams which are controlled with those electric signals are multiplexed and converged at the position of the optical logical arithmetic operation element 20 through a multiplexing system 16. Consequently, the light signals which have many wavelengths are processed simultaneously and independently, so the size of the spatial parallel optical arithmetic unit can be reduced.
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公开(公告)号：JPH08125264A
公开(公告)日：1996-05-17
申请号：JP26381294
申请日：1994-10-27
Applicant: AGENCY IND SCIENCE TECHN , YOKOGAWA ELECTRIC CORP
Inventor： HIDAKA TATSUHIKO , HIRATA TAKAAKI , TACHIKAWA YOSHIHIKO
Abstract: PURPOSE: To simultaneously oscillate a semiconductor laser in a prescribed plurality of wavelengths, to miniaturize the laser and to lower the production cost of the laser by a method wherein a periodical phase shift is provided in the diffraction grating of the semiconductor laser and a plurality of reflection peaks are provided in the reflection spectrum of the diffraction grating. CONSTITUTION: A diffraction grating 9 is held formed on the upper surface of an n-type InP clad layer 2 by an electron beam exposure method and etching, for example, prior to a crystal growth of an n-type InGaAsP guide layer 3 and a period A corresponding to the primary diffraction grating is about 240nm. When a periodical phase shift is provided in the diffraction grating, the threshold gain of a semiconductor laser, which is oscillated in a plurality of wavelengths in every period M, is reduced and it becomes possible to produce simultaneously a laser beam of a plurality of wavelengths. Moreover, as this period M is decided by the period of the phase shift, a plurality of wavelengths, which are simultaneously oscillated, can be selected by selecting properly the period of the diffraction grating and the period of the phase shift. Accordingly, a multitude of the gain peak wavelengths of an active layer in correspondence with the wavelengths of the laser, whose threshold gain is reduced, are reduced and the number of wavelengths, which can be simultaneously oscillated, is increased.
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Patent Agency Ranking
公开(公告)号：JPH0636459B2
公开(公告)日：1994-05-11
申请号：JP17439688
申请日：1988-07-13
Applicant: AGENCY IND SCIENCE TECHN
Inventor： HIDAKA TATSUHIKO
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公开(公告)号：JPH06337320A
公开(公告)日：1994-12-06
申请号：JP14863993
申请日：1993-05-27
Applicant: AGENCY IND SCIENCE TECHN
Inventor： MATSUBARA KOJI , HIDAKA TATSUHIKO , YAJIMA HIROYOSHI
Abstract: PURPOSE:To three-dimensionally produce optical waveguides within a photosensitive layer in order to improve the scale of integration of optical integrated circuits. CONSTITUTION:A body 1 which is to be exposed and is formed by providing the surface of a substrate 1a with the photosensitive layer 1b consisting of a photosensitive material, such as photopolymer, which is changed in refractive index of a photosensitive part by photoirradiation and can immobilize this photosensitive part is set on an X-Y-Z stage 2 and a laser beam is condensed to a converging light by a lens system 7. The focal position of this light is moved relative to the photosensitive layer 1b, by which the photosensitive part 1c is formed. An optical waveguide pattern 1d is formed by immobilizing this part.
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公开(公告)号：JPH0225087A
公开(公告)日：1990-01-26
申请号：JP17439688
申请日：1988-07-13
Applicant: AGENCY IND SCIENCE TECHN
Inventor： HIDAKA TATSUHIKO
Abstract: PURPOSE:To enable the supermulti-oscillation of a semiconductor laser by a method wherein a laser and a distributed reflecting section are formed on the same position on the same substrate to form the semiconductor laser of a Fourier resultant wave type structure. CONSTITUTION:In a distributed reflection type semiconductor laser which oscillates concurrently in two wavelengths, if the period of a distributed reflection section 3 is l, l is represented by an equation, l=l/2ne (where ne denotes the refractive index of the distributed reflection section 3). Therefore, if l is made to change, the semiconductor laser oscillates in different wavelengths correspondingly. And, if the distributed reflection section 3 is constituted in such a manner that the laser oscillate a resultant wave that two wavelengths lambda1 and lambda2 of two periods l1(=lambda1/2ne) and l2 (=lambda2/2ne) are compounded together, the reflectivity of this part from an active section 2 side as a basis is high toward the wavelengths lambda1 and lambda2. In the combination of a reflector and a laser obtained as mentioned above, if an interval between lambda1 and lambda2 is large to a certain extent, light rays of the wavelengths lambda1 and lambda2 can be concurrently oscillated, so that wavelengths lambda1, lambda2... can be set independently of each other.
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公开(公告)号：JPH08125265A
公开(公告)日：1996-05-17
申请号：JP26381394
申请日：1994-10-27
Applicant: AGENCY IND SCIENCE TECHN , YOKOGAWA ELECTRIC CORP
Inventor： HIDAKA TATSUHIKO , HIRATA TAKAAKI , IIO SHINJI , SUEHIRO MASAYUKI , TACHIKAWA YOSHIHIKO
Abstract: PURPOSE: To form a diffraction grating provided with periodically specified phase shifts in a dummy manner by a method wherein two kinds of the phase shifts, which have amounts of phase shift different from each other, are alternately provided in the diffraction grating and at the same time, the sum of the amounts of the two kinds of the phase shifts is specified. CONSTITUTION: An n-type InP clad layer 2, an n-type InGaAsP guide layer 3, an undoped InGaAsP active layer 4, a p-type InP clad layer 5 and a p-type InGaAsP contact layer 6 are laminated in order on the upper surface of an n InP substrate 1. Moreover, an n-type electrode 7 is mounted to the lower surface of the substrate 1, while a p-type electrode 8 is mounted to the upper surface of the layer 6. A diffraction grating 9 is formed on the upper surface of the layer 2 with phase shifts 10 of 144 degrees and phase shifts 11 of 216 degrees alternately and periodically in the direction of a resonator. The sum of the 144 degrees and the 216 degrees is 360 degrees.
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公开(公告)号：JPS63246883A
公开(公告)日：1988-10-13
申请号：JP8138987
申请日：1987-04-02
Applicant: AGENCY IND SCIENCE TECHN
Inventor： HIDAKA TATSUHIKO
Abstract: PURPOSE:To expand a tunable wavelength range, by arranging an acoustooptic element, which interferes with an incident laser beam for exciting sound waves, at a position, to which the laser beam from a semiconductor laser is inputted, at the outside of the semiconductor laser. CONSTITUTION:A laser beam from a main body 11 of a semiconductor laser is inputted in an acoustooptic element 13 through a collimating lens 12. An electroacoustic transducer element 14 and a high frequency power source 15 for exciting a suitable sound wave for the acoustooptic element 13 are provided. The main body 11 of the laser can be arbitrarily formed, but it is desirable to attach a reflection preventing film on the surface facing the lens 12. As a principle, a sound wave having a suitable wavelength and an intensity is formed in the acoustooptic element (TeO2) 13 through the electroacoustic transducer 14, and DFB (distribution feedback) action is imparted to the sound wave. Thus the oscillating wavelength of the semiconductor laser can be varied in a broad range only by the electric signal. The variable range reaches the intrinsic gain width (about 10 TH2) of the semiconductor laser and can be made as large as two orders of magnitude that of a conventional current injection type DFB laser.
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