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

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 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.

In a transparent laminate, n thin-film units (n=3 or 4) are laminated unit by unit successively on a surface of a substrate, and a high-refractive-index transparent thin film is deposited on a surface of the laminate of the n thin-film units, each of the n thin-film units consisting of a high-refractive-index thin film and a silver transparent conductive thin film. When the silver transparent conductive thin films are deposited by a vacuum dry process, the temperature T(K) of the transparent substrate at the time of film deposition is set to be in a range 340≦T≦410, whereby the transparent laminate having a standard deviation of visible light transmittance which is not larger than 5% in a wave range of from 450 to 650 nm can be produced.

A polarizer in which parallel transmittance T_P is increased and crossed transmittance T_C is provided. Instead of arranging a plurality of all metal wires on one plane, a plurality of metal wires is separately formed on at least two different parallel planes, and adjacent meal wires among the plurality of metal wires are staggered in the polarizer. The heights of a first group of metal wires formed on a first plane and a second group of metal wires formed on a second plane, from a surface of the light-transmitting substrate are different. Further, a metal wire of the second group is provided to be more distant from the light-transmitting substrate than the first group of metal wires by distance D, and the distance D is smaller than the thickness of the first group of metal wires.

A higher order mode dispersion compensating fiber includes an optical fiber and a first loss layer which is provided within the fiber and which attenuates a lower order mode propagating through the optical fiber while not attenuating a higher order mode which is higher than the lower order mode. A dispersion compensating fiber mode converter for a higher order fiber includes a single mode fiber; a higher order mode dispersion compensating fiber; and a fused and extended portion which has been formed by fusing and extending the single mode fiber and the higher order mode fiber. The fused and extended portion converts between the LP₀₁ mode of the single mode fiber and the LP₀₂ mode of the higher order mode dispersion compensating fiber.

An optical system for transmitting a source image is provided. Light having a field angle spectrum emanates from the source image. The optical system includes an optical waveguide arrangement, in which light can propagate by total internal reflection. The optical system also includes a diffractive optical input coupling arrangement for coupling the light emanating from the source image into the optical waveguide arrangement. The optical system further includes a diffractive optical output coupling arrangement for coupling the light that has propagated in the optical waveguide arrangement out from the optical waveguide arrangement. The disclosure also provides related methods.

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.

A color filter (30) includes a black matrix (33), and the black matrix has a first antireflection layer (331) and a second antireflection layer (332) on the first antireflection layer. Each antireflection layer includes a first antireflection film (3311, 3321) having a first refraction index, and a second antireflection film (3312, 3322) having a second refraction index which is different to the first refraction index. Because of so-called destructive interference of outside source light beams reflected from various interfaces defined by the first and second antireflection films, net reflection of the light beams by the black matrix back to an outside of the color filter is minimal. For similar reasons, net reflection of internal source light beams by the black matrix back to an inside of the color filter is minimal. As a result, visibility of a liquid crystal display device (300) employing the color filter is improved.

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 low coherence interferometry imaging system comprising a common-path interferometer that is at least partially integrated as part of a planar lightwave circuit is disclosed. Imaging systems in accordance with the present invention are implemented in integrated optics without the inclusion of highly wavelength-sensitive components. As a result, they exhibit less wavelength dependence than PLC-based interferometers of the prior art. Further, the common-path interferometer arrangement of the present invention avoids polarization and wavelength dispersion effects that plague prior-art PLC-based interferometers. Still further, an integrated common-path interferometer is smaller and less complex than other integrated interferometers, which makes it possible to integrate multiple interferometers on a single chip, thereby enabling multi-signal systems, such as plane-wave parallel OCT systems.

It is an object of the present invention to provide a control technique for reducing wavelength dependence of wavelength dispersion values and also for suppressing a change in wavelength transmission characteristic with a temperature variation or the like, in a VIPA-type wavelength dispersion compensator. In order to achieve the object, the present VIPA-type wavelength dispersion compensator comprises: a VIPA plate capable of emitting incident lights in different directions according to wavelengths; a free-form surface mirror reflecting, at a previously set position, the lights of respective wavelengths emitted from the VIPA plate to return the reflected lights to the VIPA plate; a case provided with a heater which variably changes the temperature of the VIPA plate, a temperature sensor measuring the temperature of the VIPA plate and the ambient temperature; and a control section that reads out data which is measured or the like before starting the operation to be stored in a storing section, according to the measurement result of the temperature sensor, and optimizes the position of the free-form surface mirror and the temperature of the VIPA plate based on the read data.

A method of spatially relaying a first radiation component (1) having a first wavelength and a second radiation component (2) having a second wavelength different from the first radiation component (1), using an optical relaying device (10) which comprises a transparent plate (11) having anti-reflection coatings (12, 13) on both side surfaces thereof, comprises transmitting the first radiation component (1) across the optical relaying device (10) with predetermined incident (a) and emergent angles (β), resp., wherein said anti-reflection coatings (12, 13) being effective for the first radiation component (1) at the incident and emergent angles (α, β), resp., and reflecting the second radiation component (2) at the optical relaying device (10) with a predetermined reflection angle (a) being equal to at least one of said incident and emergent angles (α, β), wherein the first and second radiation components (1, 2) are split from each other toward different directions or combined into a common beam path. Furthermore, an optical relaying device (10) and a resonator device, in particular enhancement cavity device (100) and a laser resonator, are described.

A method for manufacturing a gray-tone mask that decreases the wavelength dependency with respect to an exposure wavelength under stable and simple film formation conditions. A reactive sputtering method that sputters a pure Cr target in an atmosphere of Ar and NO is used to form a Cr nitride film having a single-layer structure. Based on a plurality of different spectral transmittance curves obtained under a plurality of film formation conditions having different NO concentrations, a target concentration (intermediate value) for NO is obtained that sets the transmittance uniformity of the semi-transparent film to 1.0% or less in the range of 365 nm to 436 nm or 4.0% or less in the range of 300 nm to 500 nm. Then, a semi-transparent film is formed by using the NO target concentration.

An optical hybrid lens comprises a substrate having a first surface and a second surface opposite the first surface. A sub-wavelength grating lens is disposed on the first surface and comprises a plurality of posts. The plurality of posts is arranged on the first surface and the posts extend from the first surface. A refractive lens is arranged on the sub-wavelength grating lens at least partly enclosing the plurality of posts. Alternatively, the refractive lens is arranged on the second surface.