Abstract: The present invention is provided to obtain an inexpensive bidirectional optical module wherein a diffraction efficiency can be maximized at different diffraction order for light beam with different wavelength, and light usage efficiency is enhanced. The bidirectional optical module includes a light-emitting element for transmitting an optical signal toward an end of an optical fiber; a light-receiving element for receiving an optical signal from the end of the optical fiber; and a grating in which stair shapes are repeated with a predefined pitch. In the bidirectional optical module, a phase function is defined as phase-difference contour lines which is formed by making two light fluxes from predetermined positions interfere with each other on a surface arranged at a position of the grating. A planar pitch of the grating is formed such that values of the phase function form phase contour lines each representing an integer multiple of 360 degrees.

Abstract: An inexpensive optical bi-directional module by which diffraction efficiency of light beams having different wavelengths can be maximized at different diffraction orders, respectively, and light utilization efficiency is enhanced. The optical bi-directional module comprises a light emitting element for transmitting an optical signal toward the end of an optical fiber, a light receiving element for receiving an optical signal from the end of the optical fiber, and a grating having stepwise profiles repeated at a desired pitch. Assuming the position of the grating is on the DOE plane and the light emitting elements are located, respectively, at the end of the optical fiber and the position of the light receiving element, planar pitch of the grating is set such that a phase function being given as an equiphase-difference line on the DOE plane by causing interference of two light beams of the assumed light emitting elements has a phase function value representing an equiphase curve of integral multiples of 360°.

Abstract: A producing method of an optical element such as quarter-wave plate wherein preparing a first member which has a coefficient of elasticity of 1-4 (GPa) at normal temperature, setting the temperature of a die having microscopic shape with high aspect ratio to be higher than the glass transition temperature of the first member and pressing the die against the first member to transfer a microscopic shape on the first member, a microstructure is formed on the first member. In the same manner, a second microstructure is formed on a second member. Afterwards, by connecting the first member and the second member, an optical element in which the first member and the second member are connected having microstructures with high aspect ratio face each other, is obtained.

Abstract: A article having a micro-sized shape being formed on the surface of the article by pressing a die onto the surface, wherein the elastic modulus of the article at room temperature is in the range of 1-4 GPa, the thickness of the article after forming is equal to 0.1 mm or more and 20 mm or less and the aspect ratio of the micro-sized shape is equal to 1 or more. A forming method to produce an article comprising the steps of setting the temperature of a die having a micro sized shape to be equal or higher than the glass transitional temperature of material having an elastic modulus of 1 to 4 (GPa) pressing the die to the material to transfer the micro sized shape to the material, and cooling the die having the micro sized shape.

Abstract: An optical element holding structure, having: an optical element including an optical section having optical function, an outer peripheral portion which is positioned at the outer peripheral side of the optical section and a mounting portion which protrudes from the outer peripheral portion in a direction substantially parallel to the optical axis; and a lens barrel holding the optical element inside.

Abstract: There is described a molding method for molding a product, having a microscopic structure of high aspect ratio. The molding method includes the steps of: setting a temperature of a mold, having a microscopic shape, at a value higher than a glass transition temperature of a material being deformable with heat; pushing the mold against the material at a first velocity, after the material is positioned opposite to the mold so that the microscopic shape contacts the material; pushing the mold against the material at a second velocity being faster than the first velocity; and releasing the mold from the material. The pushing pressure for pushing the mold against the material at the first velocity is equal to or smaller than a half of that for pushing the mold against the material at the second velocity.

Abstract: A wide-band wave plate having at least two wave plates, each of which has a microstructure to generate a phase difference, the microstructure having a cycle not shorter than 1/nmin of a shortest wavelength of light in use, wherein the two wave plates are arranged to face opposite with their main axes in non-parallel with each other, wherein nmin is a refractive index of a wave plate material with respect to the shortest wavelength.

Abstract: There is described a method for depicting a predetermined pattern, such as a diffraction pattern employed in an optical element, on a substrate. The method includes the steps of: acquiring shape data of the predetermined pattern; generating a first input signal for deflecting an electron beam emitted from an electron gun in a main-scanning direction, and a second input signal for deflecting the electron beam in a sub-scanning direction, based on the shape data of the predetermined pattern; adjusting an alternating bias signal, having a specific frequency, according to the shape data of the predetermined pattern; superposing the alternating bias signal on the second input signal; and deflecting the electron beam emitted from the electron gun in the sub-scanning direction according to the second input signal on which the alternating bias signal is superposed, while scanning the electron beam by deflecting it in a main-scanning direction.

Abstract: A method of working an optical element for producing an optical element having a microscopic pattern, comprising a pattern drawing step for forming a specified pattern corresponding to said optical element on a base material including a layer of pattern drawing object, wherein said layer of pattern drawing object has a curved surface, and said specified pattern is drawn by the application of an electron beam to said layer of pattern drawing object.

Abstract: A article having a micro-sized shape being formed on the surface of the article by pressing a die onto the surface, wherein the elastic modulus of the article at room temperature is in the range of 1-4 GPa, the thickness of the article after forming is equal to 0.1 mm or more and 20 mm or less and the aspect ratio of the micro-sized shape is equal to 1 or more. A forming method to produce an article comprising the steps of setting the temperature of a die having a micro sized shape to be equal or higher than the glass transitional temperature of material having an elastic modulus of 1 to 4 (GPa) pressing the die to the material to transfer the micro sized shape to the material, and cooling the die having the micro sized shape.

Abstract: A article having a micro-sized shape being formed on the surface of the article by pressing a die onto the surface, wherein the elastic modulus of the article at room temperature is in the range of 1–4 GPa, the thickness of the article after forming is equal to 0.1 mm or more and 20 mm or less and the aspect ratio of the micro-sized shape is equal to 1 or more. A forming method to produce an article comprising the steps of setting the temperature of a die having a micro sized shape to be equal or higher than the glass transitional temperature of material having an elastic modulus of 1 to 4 (GPa) pressing the die to the material to transfer the micro sized shape to the material, and cooling the die having the micro sized shape.

Abstract: An echelon type diffraction structure 5a is formed on the flat optical surface of a lens 5, thereby ensuring easy designing and easy production of a diffraction structure as a microstructure. Further, the light of wavelength ?1 is applied to the diffraction structure 5a in a tilted position with respect to the optical axis of the lens 5 so that the first order diffracted light produced by the diffraction structure 5a travels along or parallel to the optical axis of the lens 5, with the result that improved light transmittance can be maintained. Further, a lens 7b is arranged between a light emitting device 7a and lens 5. Thus, the flat optical surface of the lens 5 is arranged on the side of the end face 1a of an optical fiber 1, thereby reducing the deterioration in aberration more effectively.

Abstract: A wide-band wave plate having at least two wave plates, each of which has a microstructure to generate a phase difference, the microstructure having a cycle not shorter than 1/nmin of a shortest wavelength of light in use, wherein the two wave plates are arranged to face opposite with their main axes in non-parallel with each other, wherein nmin is a refractive index of a wave plate material with respect to the shortest wavelength.

Abstract: A method of producing an optical element forming die, includes the steps of: cutting a base member to form a base optical surface of the base member while rotating the base member; cutting an outer circumferential surface of the base member so that an optical axis of the base optical surface is identical to a rotation center of the outer circumferential surface of the base member while rotating the base member; forming an optical surface having a predetermined pattern onto the base optical surface of the base member; forming an electroforming mold having an optical transfer surface complementary to the optical surface of the base member by electroforming wherein the electroforming is conducted with the base member; and cutting an outer circumferential surface of the electroforming mold on the basis of the outer circumferential surface of the base member.

Abstract: An optical bidirectional module 10 having therein light emitting element 11 which transmits optical signal to the end facet of the optical fiber, light receiving element 12 which receives optical signal from the end facet of the optical fiber and stair-shaped multi-level grating 15, wherein the stair-shaped multi-level grating separates the first light path between the end facet of optical fiber and the light emitting element and the second light path between the end facet of optical fiber and the light receiving element by a different wavelength of each optical signal, when the module mixes and separates optical signal with different wavelengths traveling in opposite directions related to the end facet of the optical fiber 1, used for bidirectional optical fiber communication by means of a wavelength multiplex system.

Abstract: An optical element holding structure, having: an optical element including an optical section having optical function, an outer peripheral portion which is positioned at the outer peripheral side of the optical section and a mounting portion which protrudes from the outer peripheral portion in a direction substantially parallel to the optical axis; and a lens barrel holding the optical element inside.

Abstract: A pattern drawing method of drawing a desired pattern on a base material by irradiating an electronic beam and scanning the base material with the electronic beam with a predetermined dose amount, comprising: a first step of drawing a first region on the base material by scanning with the electronic beam with a first dose amount; a second step of drawing a second region on the base material by scanning with the electronic beam with a second dose amount; and a inclining step of inclining a boundary between the first region and the second region to form an inclined surface by conducting a first scanning to scan with the electronic beam with the first dose amount and a second scanning to scan with the electronic beam with the second does amount in a mixed arrangement.

Abstract: An echelon type diffraction structure 5a is formed on the flat optical surface of a lens 5, thereby ensuring easy designing and easy production of a diffraction structure as a microstructure. Further, the light of wavelength ?1 is applied to the diffraction structure 5a in a tilted position with respect to the optical axis of the lens 5 so that the first order diffracted light produced by the diffraction structure 5a travels along or parallel to the optical axis of the lens 5, with the result that improved light transmittance can be maintained. Further, a lens 7b is arranged between a light emitting device 7a and lens 5. Thus, the flat optical surface of the lens 5 is arranged on the side of the end face 1a of an optical fiber 1, thereby reducing the deterioration in aberration more effectively.

Abstract: A producing method of an optical element such as quarter-wave plate wherein preparing a first member which has a coefficient of elasticity of 1-4 (GPa) at normal temperature, setting the temperature of a die having microscopic shape with high aspect ratio to be higher than the glass transition temperature of the first member and pressing the die against the first member to transfer a microscopic shape on the first member, a microstructure is formed on the first member. In the same manner, a second microstructure is formed on a second member. Afterwards, by connecting the first member and the second member, an optical element in which the first member and the second member are connected having microstructures with high aspect ratio face each other, is obtained.

Abstract: A plasma etching method for processing a substrate material, wherein a deposition process (S09) that uses a deposition gas as a process and an etching process (S11) that uses an etching gas as a process gas are alternately and repeatedly executed, thereby etching a substrate material, and a vacuuming process (S10, S13) is interposed between the two processes so that the process gas which has just finished being used is expelled out when the process gases are switched. Thus, the etching gas and the deposition gas do not mix during each process, thereby accurately creating a high-aspect-ratio recessed and protruding pattern on the surface of a substrate material.