86 results about "Attenuation loss" patented technology

Light diffusing optical fibers and methods for producing light diffusing optical fibers are disclosed. In one embodiment, a light diffusing optical fiber includes a core portion formed from silica glass and comprising a plurality of helical void randomly distributed in the core portion of the optical fiber and wrapped around the long axis of the optical fiber. A pitch of the helical voids may vary along the axial length of the light diffusing optical fiber in order to achieve the desired illumination along the length of the optical fiber. A cladding may surround the core portion. Light guided by the core portion is scattered by the helical voids radially outward, through the cladding, such that the light diffusing optical fiber emits light with a predetermined intensity over an axial length of the light diffusing optical fiber, the light diffusing optical fiber having a scattering induced attenuation loss greater than about 0.2 dB/m at a wavelength of 550 nm.

The present invention relates to a transmission optical fiber. The optical fiber includes, from its center to its periphery a central core, an intermediate cladding, and a depressed cladding. The optical fiber has an effective area (S_eff) of at least about 120 μm² at a wavelength of 1550 nm and an effective cutoff wavelength (λ_Ceff) of less than 1600 nm. The optical fiber has an effective area of more than 120 μm² with a cutoff wavelength limited to less than about 1600 nm without degradation of other optical parameters (e.g., attenuation losses and dispersion).

An optical fiber resistant to hydrogen-induced attenuation losses at both relatively low and relatively high temperatures includes a substantially pure silica core and a hydrogen retarding layer. The hydrogen retarding coating may be made of carbon, metal, or silicon nitride. The fiber may also include a cladding layer, a second silica layer, and a protective outer sheath.

A method for controlling attenuation losses caused by microbending on the signal transmitted by an optical fiber having an internal glass portion. A first coating layer of a first polymeric material surrounds the glass portion and a second coating layer of a second polymeric material surrounds the first coating layer. The first polymeric material has a hardening temperature lower than 10° and an equilibrium modulus lower than 1.5 MPa.

The invention discloses a terahertz wave band wireless transmitting and receiving device and a transmitting and receiving method thereof. The transmitting and receiving device comprises a transmitting terminal composed of a first cold head, a terahertz quantum-cascade laser and a first polyethylene window plate, an optical path part containing two off-axis parabolic mirrors and air and a receiving terminal composed of a second cold head, a terahertz quantum well detector and a second polyethylene window plate. The invention has the advantage that currently undistributed frequency range of electromagnetic wave is selected to transmit and receive electromagnetic wave, the absorption of the selected frequency point of electromagnetic wave by the air is relatively weaker, thus reducing the attenuation loss of terahertz wave during the transmission process; the semiconductor quantum-cascade laser which has high energy conversion efficiency and small volume, is easy to integrate, and can work for long time and perform mass production is adopted by the transmitting terminal; the semiconductor quantum well detector which has small volume, is stable and reliable and can perform mass production is adopted by the receiving terminal; and the adopted semiconductor laser and detector both can operate at high frequency, thus being suitable for future terahertz communication applications.

In a ring network comprising a plurality of nodes and a 16 channel coarse wavelength-division multiplexing (CWDM) plan, a technique is disclosed for adding and dropping channels that reduces the maximum attenuation loss that any channel encounters—thereby enabling longer rings to be constructed without using optical amplifiers in the ring. The 16 channels are typically distributed between the wavelengths 1310–1610 nm with 20 nm separation between channels. It is obscured that glass fibers have gradually decreasing loss at longer wavelengths in this band. The network includes a hub and several nodes that are interconnected by optical fibers in a ring configuration, where distance from the hub is the minimum value measure in either the clockwise or counterclockwise direction. Channels are assigned to the various nodes based on their wavelength. The channels whose wavelengths are near 1310 nm are assigned to nodes that are progressively closer to the hub.

The invention relates to an optical fiber integration antenna and a signal transmission method which are an antenna device and a signal transmission method used in a wireless communication base station in a wireless communication network. The optical fiber integration antenna comprises an antenna assembly arranged outdoors, the antenna assembly is connected with an optical fiber remote far-end processing unit via a micro-distance radio frequency connecting assembly, the optical fiber remote far-end processing unit is connected with a long-distance optical cable, and the long-distance optical cable is connected with an optical fiber remote near-end processing unit and an information source device in a generator room. The invention ensures that the antenna assembly and the optical fiber remote far-end processing unit are installed together and are connected by the micro-distance radio frequency connecting assembly, which saves coaxial cables and ensures that the attenuation loss between the antenna assembly and the optical fiber remote far-end processing unit is minimum, and the installation of the whole set of antenna device is convenient. Because an optical signal transmission is used between the information source device and the antenna, the transmission quality is high, so that communication quality is improved to certain extent, which is favourable for 3G communication.

The invention relates to the field of photovoltaic technologies and discloses a photovoltaic cell module terminal box of a wiring window free of bus bars on the surface. The photovoltaic cell module terminal box of the wiring window free of the bus bars on the surface comprises a plastic box body for an output wire cable to be connected in a sealed mode, wherein an opening is formed at the bonding position of the back side of the plastic box body and a photovoltaic cell module back board or glass, the front side and the lateral side of the plastic box body are airtight and free of windows, wiring terminals with the same number as the bus bars led out of photovoltaic cell module back board or the glass are arranged in the plastic box body, a bypass diode is connected between adjacent wiring terminals, the wiring terminals at two ends are respectively connected with positive and negative poles of the output wire cable and respectively provided with heat-dissipation conductive metal pieces, and diodes are arranged on the heat-dissipation conductive metal pieces. The photovoltaic cell module terminal box is simple in structure, the surface of the plastic box body is airtight and free of windows, the heat dissipation effect is ideal, the electricity generation attenuation loss is reduced, waterproof reliability is good, installation operation is convenient, and the manufacturing and follow-up installation and usage cost of the terminal box is remarkably reduced.

The invention discloses a low-loss high-speed cable and a flat cable. The low-loss high-speed cable comprises a wire core group, a first shielding layer, a second shielding layer and an outer coatinglayer; the first shielding layer wraps the wire core group; the second shielding layer wraps the first shielding layer; and the outer coating layer coats the second shielding layer; the wire core group comprises two inner conductors; two first fluorinated ethylene propylene insulating layers respectively cover the two inner conductors; and the two first fluorinated ethylene propylene insulating layers are covered with a second fluorinated ethylene propylene insulating layer which is formed by simultaneous extrusion molding. The wire rod of the low-loss high-speed cable of the invention is soft; the low-loss high-speed cable has high temperature resistance; the shielding layers of the low-loss high-speed cable can achieve full shielding; and the dielectric constant consistency of the low-loss high-speed cable is relatively high. With the low-loss high-speed cable adopted, signal attenuation loss can be reduced.

A DTS system resistant to radiation induced attenuation losses during the service life of an installation at both low and high temperatures using matched multi-wavelength distributed temperature sensing automatic calibration technology in combination with designed Pure Silica Core (PSC) optical fibers and an in process photo bleaching method provided by the light sources of the distributed temperature sensing system.

The invention discloses a high/low temperature-resistant nylon composite material and a preparation method thereof. The high/low temperature-resistant nylon composite material comprises the following components: 55-85 parts of aliphatic nylon 12, 5-25 parts of nylon 610, 5-10 parts of nylon 612, 1-15 parts of a cycloolefin copolymer, 0.5-5 parts of a compatilizer, 0.1-1 part of a hindered phenol antioxidant, 0.1-0.5 part of a copper salt compound antioxidant, 2-3 parts of N-butylbenzene sulfonamide and 0.2-1 part of N,N-dimethyl-p-toluenesulfonamide, wherein the relative viscosities of the aliphatic nylon 12, the nylon 610 and the nylon 612 are below 2.7; the cycloolefin copolymer is selected from ethylene with density of 1.01+/-0.01 g/cm<3> and a norbornene copolymer TOPAS resin; the compatilizer is selected from maleic anhydride grafted amorphous polyolefin. The high/low temperature-resistant nylon composite material is difficult to crystallize, high in transparency and low in coefficient of thermal expansion, and has the advantages of greatly improving the problem of high optical attenuation loss and further improving the mechanical strength of the material.

The invention provides a system and a method for detecting coupling performance of a radio frequency circuit and an antenna of a wireless router. The system comprises a radio frequency test device, an antenna coupling test apparatus and a terminal. The radio frequency test device comprises a radio frequency circuit and an omnidirectional antenna, the radio frequency circuit is used for performing transmitting and receiving of frequency under a wireless mode, and the omnidirectional antenna is connected with the radio frequency circuit, mounted at a port of the radio frequency test device and used for receiving signals transmitted by the wireless router in a coupling manner; the antenna coupling test apparatus is used for placing a to-be-tested device and calculating air attenuation loss between the antenna of the to-be-tested device and the omnidirectional antenna under the condition of different distance therebetween; and the terminal is used for setting different wireless mode channel frequency, and testing a coupling performance index of the radio frequency circuit and the antenna of the to-be-tested device according to the air attenuation loss under the condition of different distance and different frequency. According to the invention, a problem of matching of the radio frequency circuit and the antenna is located quickly without damage to products, thus, product performance is improved, and test efficiency is increased.

The invention discloses a floor structure which can improve the isolation between antennas. A plurality of upper crenels and lower crenels with identical structures are arranged on the floor, the widths of the upper crenels and the lower crenels are equal, and a lower crenel is arranged between two adjacent upper crenels; conversely an upper crenel is arranged between two adjacent lower crenels; and a transmitting microstrip antenna and a receiving microstrip antenna are respectively connected with both ends of the floor. The floor structure improves the electromagnetic interference between airborne antennas. The method prolongs the transmission path of the electromagnetic wave between interference antennas, increases the attenuation loss of the electromagnetic wave, and can basically improve the isolation between the antennas in the acceptable antenna radiation characteristic distortion range.

Fiber optic assemblies include subunit cables wrapped in binders. The assemblies have small cross sections and low bend radii while maintaining acceptable attenuation losses. SZ stranding of the subunit cables allows ease of access to the individual cables during installation.

The invention relates to a porous nano-material, which comprises primary particles and second particles which are composed of primary particles. The invention also relates to a sound attenuator based on the porous nano-material, and the sound attenuator is prepared from the porous nano-material. The superior effects of the porous nano-material and the sound attenuator based on the porous nano-material are as follows: the porous nano-material has light weight and thin thickness with excellent sound insulation performance, and the panel of the porous nano-material is made into different shapes according to needs, and the sound attenuation loss of the porous nano-material is not lower than 20-100 db/cm; the sound attenuator based on the porous nano-material is suitable for various environments with popularization value.