44results about How to "Low wavelength dependence" patented technology

Disclosed are a wire grid polarizer, which exhibits high polarization, p-polarized light transmittance, and s-polarized light reflectance in the visible light region, and the optical characteristics of which have low angular dependence and wavelength dependence, and a manufacturing method for the same. A wire grid polarizer (10) comprises a light transmissive substrate (14), on the surface of which a multiplicity of convex strips (12), the width of which gradually narrows from the base to the apex, is formed parallel to one another with intervening flat spots (13) formed between the convex strips (12), and at a specified pitch (Pp), and a metallic layer (20), which covers the entire surface of a first side face (16) of the convex strip (12) and a portion of the flat spot (13) adjacent thereto, and either does not cover a second side face (18) of the convex strip (12) or covers a portion of a second side face (18); and a manufacturing method forms a metallic layer (20) by vapor depositioning a metal or metal compound from a direction that is substantially orthogonal to the length direction of the convex strips (12) and forms a 25-40 DEG angle relative to the height direction of the convex strips (12) on the side of the first side face (16), under conditions in which the deposition amount is 40-60 nm.

A broadband optical fiber tap for transferring optical energy out of an optical fiber having an optical fiber with a primary and secondary microbends for the purpose of coupling optical energy into the higher-order modes of the fiber, and a reflecting surface formed in the cladding of the fiber and positioned at an angle so as to reflect, by total internal reflection, higher-order mode energy away from the optical fiber. In the preferred embodiment, the two microbends are spaced apart by a distance approximately equal to one-half of the intermodal beat length for LP01 and LP11 modes of a single-mode fiber.

A diffraction grating having a transparent supporting substrate; and a cured resin layer which is stacked on the transparent supporting substrate and which has concavities and convexities formed on a surface thereof, wherein when a Fourier-transformed image is obtained by performing two-dimensional fast Fourier transform processing on a concavity and convexity analysis image obtained by analyzing a shape of the concavities and convexities formed on the surface of the cured resin layer by use of an atomic force microscope, the Fourier-transformed image shows a circular or annular pattern substantially centered at an origin at which an absolute value of wavenumber is 0 μm−1, and the circular or annular pattern is present within a region where an absolute value of wavenumber is within a range of 10 μm−1 or less.

A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light. In the Raman amplifier according to the present invention, when a certain pumping wavelength is defined as a first channel, and second to n-th channels are defined to be arranged with an interval of about 1 THz toward a longer wavelength side, the pumping lights having wavelengths corresponding to the first to n-th channels are multiplexed, and an pumping light having a wavelength spaced apart from the n-th channel by 2 THz or more toward the longer wavelength side is combined with the multiplexed light, thereby forming the pumping light source. The pumping lights having wavelengths corresponding to the channels other than (n-1)-th and (n-2)-th channels may be multiplexed, thereby forming the pumping light source. The pumping lights having wavelengths corresponding to the channels other than (n-2)-th and (n-3)-th channels may be multiplexed, thereby forming the pumping light source.

A waveguide-type broadband optical isolator according to the present invention, comprising: a reciprocal phase shifter which makes a phase difference 3π / 2 between a first light wave propagating through a first waveguide and a second light wave propagating through a second waveguide, with a fundamental operating wavelength λ, and a nonreciprocal phase shifter which provides a phase difference π / 2 for forward propagating waves and a phase difference −π / 2 for backward propagating waves.

To provide optical elements such as a phase plate suitably used in a broadband range and a polarizing diffraction element excellent in diffraction efficiency, a polymerizable liquid crystal composition to be used for them, and an optical head device using them.A polymerizable liquid crystal composition containing a polymerizable compound having a mesogen structure comprising the following condensed benzene ring group (A) and the following 6-membered cyclic group (B) bonded to at least one bond in the group (A) directly or via a connecting group —OCO— or —COO—, and a monovalent terminal group bonded to each of both terminals of the mesogen structure, at least one of the terminal groups being a monovalent organic group having a polymerizable moiety:condensed benzene ring group (A): a naphthalenediyl group having bonds at 1-position and at 4- or 5-position, or an anthracenediyl group having bonds at 1- or 9-position and at 4-, 5- or 10-position;6-membered cyclic group (B): a 1,4-phenylene group, a trans-1,4-cyclohexylene group or a bivalent group having at least two groups selected from these groups bonded directly or via a connecting group.