摘要:
This invention relates to a method of making optical fiber having low polarization dependence. Light propagating through a cladding thereof has a mode group having a first eigenmode propagating at a first speed and a second eigenmode propagating at a second speed. Manufacture of the fiber is controlled so that a difference between the first and second speeds is small. A difference between the speeds divided by the first speed is preferably less than 5×10−7.
摘要:
This invention relates to an acousto-optical tunable filter generally of the kind described in U.S. Pat. No. 6,266,462. More specifically, the invention relates to a filter and its construction, the filter including a support, first and second mounts at spaced locations on the support, an optical fiber having first and second mounted portions secured to the first and second mounts respectively and a filtering section between the first and second mounted portions, a signal generator operable to generate a periodic signal, and an electro-acoustic transducer having a terminal connected to the signal generator and an actuating portion, the electric signal causing vibration of the actuating portion, and the actuating portion being connected to the filtering section so that the vibration generates a transverse wave traveling along the filtering section. The filter has an improved damper to more effectively dampen waves traveling along the filtering section.
摘要:
A method to reduce optical intensity modulation is described that involves generating a spiraling wave onto an acoustic-optic interaction portion of an optical fiber within an acousto-optic filter in order to create reflected waves that are orthogonal with respect to waves that are originally launched onto the interaction portion. A transducer is described having a first section and a second section. The first and second sections each have a polling direction along a first axis. The transducer also has a third section and a fourth section. The third and fourth sections each have a polling direction along a second axis. The third and fourth sections are each between the first and second sections. An acousto-optic filter having a horn with an elliptical cross section coupled to a transducer is also described. A transducer for an excitation element capable of launching spiraling acoustic waves is described.
摘要:
This invention relates to a method of making optical fiber having low polarization dependence and an acousto-optical filter with low PDL. A section of the fiber is heated and then allowed to cool. At least the heating is controlled to reduce stresses in a cladding layer surrounding a core of the interaction length after the interaction length is allowed to cool to reduce polarization dependence of the cladding layer. Preferably, at least time and temperature of heating is controlled.
摘要:
An interferometer-type laser sensor acts concurrently as a light source and to measure external physical quantities such as rotation, magnetic field, current and fluid velocity. The interferometer-type laser sensor has a laser resonator having a laser gain medium, optical path and two or more reflectors to reflect incident light toward an opposite direction. In addition, a device is provided for interfering light not reflecting on the said reflectors but passing through. A signal processor is provided to detect and process interference signal generated from the interfering device. The laser sensor has a distinction over the conventional passive fiber-optic gyroscope as followings: first, expensive polarization maintaining fiber or polarizer is not required, since there is no polarization error which is readily appeared at the conventional passive fiber-optic gyroscope. Secondly, wavelength-dependent errors generating during the use of a light source of wide width decrease remarkably by employing a laser of narrow width. Thirdly, an external light source is not required, since a laser resonator acts concurrently as a light source and measures external physical quantity.
摘要:
An apparatus for effectively filtering and separating fine floc, algae, suspended solids, etc. remaining in water after biological and physiochemical treatment is provided. The fine filtering apparatus includes flexible fibers that control packing density, thus improving filtration efficiency, the amount of clarified water, and filtering duration, and reducing power consumption compared to a conventional filtering apparatus is provided. In the filtering apparatus, flexible fibers having an effective diameter of 1 to 60 μm and which are flexible, elastic, and have proper surface roughness extend in the longitudinal direction of the apparatus. A jacket shaped unit for supplying source water (supplied water) has a porous structure. Clarified water (treated water) is discharged through a central porous chamber. The whole filter media layer can be utilized as a particle-entrapping space.
摘要:
The present invention relates to a power testing facility system of a train and a testing method using the same. In the present invention, there are provided a test bed for engaging a testing object, a DC power facility formed of a converter transformer and DC power converter, an AC power facility formed of a phase balancing apparatus, a voltage regulating transformer, and a power factor improving apparatus, a load facility formed of an induction generator and a bi-directional inverter, a measuring apparatus for measuring various characteristics of a propulsion apparatus, and a control apparatus for controlling the entire system. With the above elements, it is possible to implement a type test, a combination test and a train operation simulation test using a facility system adapted to test a power of a train. When selecting an instrument installed in a train, it is implement a desired reliability by testing a previously fabricated product. The facility is economically operated, and an operation cost is minimized. An easier maintenance is implemented. An electrical energy may be restored using a bi-directional inverter. A power loss is decreased. It is possible to prevent an indoor temperature increase.