OPTICAL FIBER CURRENT SENSOR
, Is a TO(transistor outline)-CAN-based ultra-small optical fiber current sensor which is easy to measure high-voltage high-voltage high- voltage measurement. The optical CT(current transformer), is easy to construct a more stable measurement system in a high voltage, large current situation than an existing electromagnetic field type CT due to an insulating, non-inductive property of an optical element using an optical current sensor. CT Is an asymmetric structure, of an optical fiber, and, is a,fiber type sensor capable of freely adjusting a range and sensitivity of an optical signal by adjusting the number of turns of, coils . however, the linear birefringence generated by bending a process of forming an asymmetric structure of the optical fiber and a coil made of an optical fiber may be adjusted to make, the optical CT. field (flint glass) application difficult, to apply to a field of the optical signal, thereby making, it difficult to apply the optical fiber to the field of the optical signal. On the other hand, or more of the transmission loss, of (2.5 dB/m) printed glass optical fiber is too large to be used as the sensor coil 5m, and the, optical fiber is not easily and stably fixed. . Is a cross-sectional view of an optical fiber current sensor according to an embodiment of the present invention. , Is a diagram, illustrating an optical fiber current sensor TOSA(Transmitter Optical Subassembly), for measuring a current flowing in a conductor using a sensor coil comprised of ROSA(Receiver Optical Subassembly) optical fibers, wherein, and TOSA are provided with an optical fiber current sensor. ROSA, and, are separated according to, polarization by polarization of light reflected from the sensor coil TOSA and ROSA are respectively packaged in the TO(transistor outline)-CAN and the. The TOSA is formed on the stem 1 TO-CAN and linearly polarizes light from the light source, and the incident key to the sensor coil may include a linear polarizer. The ROSA is formed on the stem 2 TO-CAN and includes a polarization light splitter, for separating light reflected from the sensor coil in response to polarization, and a first 2 TO-CAN and a second photo diode which are formed on 1 stems and detect light separated by the polarization. 2. ROSA, And 2, may further include a reflection mirror reflecting one of the light separated according to the polarization to enter the photo diode. ROSA And 2 TO-CAN may further include a partition formed on the at least stems to block interference between light separated by the polarization. ROSA May further include TEC(thermoelectric cooler) for maintaining a peripheral temperature of the reflection mirror. TOSA And ROSA may be integrally coupled. The ROSA may further include TEC to maintain a peripheral temperature of the polarized light separator. The optical fiber current sensor may further include a wavelength retarder that delays a wavelength of the polarized light of TOSA. TOSA Is a diagram illustrating an optical fiber current sensor according to an embodiment of the present invention, wherein the optical fiber current sensor may further include a light separator that enters the sensor coil, at ROSA and enters the light reflected from the sensor coil at. , Is a cross-sectional view of a light splitter, light source, wavelength retarder, polarized light separator. . Is . and the light detector, outputs the light to the light separator, by delaying the wavelength of the light separated from the sensor coil, and outputting the light to the light separator . and the light detector, may detect the light reflected from the sensor coil, and the light detector may be formed as a single package of the polarization light splitter. The optical fiber current sensor may further include at least one TEC maintaining a peripheral temperature of the light splitter and the polarization light separator. The package may include the at least one TEC. , TO-CAN Is a perspective view of an optical sensor according to an embodiment of the present invention, wherein the optical element, is mounted on the optical element in TO-CAN. 1 Is a diagram illustrating a principle of the optical current sensor according to an embodiment of the present invention. 2 Is a cross-sectional view of an optical fiber current sensor according to an embodiment of the present invention. 3 Schematically illustrates 2 shown in FIG. ROSA. 4 Schematically illustrates a manufacturing method of 2 shown in FIG. ROSA. 5 Is a graph illustrating an output of an agent 1 optical fiber current sensor according to an embodiment of the present invention. 6 Schematically illustrates another example of 2 shown in FIG. ROSA. 7 Schematically illustrates an optical fiber current sensor according to an embodiment 2 of the present invention. . The present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention in various different forms, parts irrelevant to the description are omitted to clearly describe the present invention, and like reference numerals denote like parts throughout the specification. , Will be understood to imply the inclusion of stated elements " or " and that, is not intended to exclude other elements but may further include other elements unless otherwise indicated. An optical fiber current sensor according to an embodiment of the present invention will now be described in detail with reference to the drawings. 1 Is a diagram illustrating a principle of the optical current sensor according to an embodiment of the present invention. To FIG. 1, a zero-light current sensor detects a current flowing in the conductor (10) using a circular birefringence change, of the optical fiber (faraday effect) formed by a magnetic field, i.e. Faraday effect (20). The optical current sensor may include a detector (10) that transmits light to a sensor coil (20) made by winding optical fiber (11) around a conductor (31), into a closed loop shape, and (11) photodetectors (32) for detecting light received from the detector coil 2 for detecting light received from the sensor coil. (33). The polarizer (31) linearly polarizes light from the light source (40) and enters, linearly polarized light into the optical fiber (10). A linearly polarized light having a polarizer (31) is optical fiber (10). When incident light, passes through the sensor coil (11), the polarization axis is rotated by (20) magnetic fields, and, is a Faraday effect, and the rotational angle ρ of, polarization axis is expressed as Equation. 1. In Equation 1, V is Verdet, and, is a constant that determines the characteristics of the Faraday device, i.e. N sensor coil, and, H denotes a magnetic field intensity and, I denotes the magnitude of the current flowing to the conductor (20). That is, when the, magnetic field is pre-integrated with the closed circuit . a current passes through the closed circuit, which is difficult to obtain when a bulk optical element other than the optical fiber (10) is used. As shown in Equation 1, the rotation angle of the polarization axis by the Faraday effect is proportional to the magnitude of the current flowing through the conductor (20), that is, the intensity of, magnetic field, and measures a, rotation angle ρ. (20). When the angle between the polarizer (31) and the detector (32) is θ, the output of the sensor coil cos is zero.2 As a result of the nonlinear transmission characteristics of θ . when θ====± 45, a linear and,sensitivity output can be obtained; therefore, the angle between, polarizers (31) and detector (32) can be set to ± 445. The detector (32) separates the output light of the sensor coil in accordance with the polarization and the light separated by, polarization is detected by 2 photodetector (33). The 2 photodetector (33) converts the light separated according to the polarization into a current value corresponding to the electric signal, and outputs the output of. 2 photodetector (33) I.1 , I2 The rotational angle ρ can be calculated from the output of the, 2 photodetector (33) by Equation 2 from the outputs of the two light detector two. That is, the output of the, 2 photodetector (33) is processed by the embedded computer to calculate the rotational angle ρ and the intensity of the current from, calculated rotational angle ρ can be measured. 2 Is a plan view of an optical fiber current sensor according to an embodiment 1 and, and FIG. 3 shows an example of 2 shown in FIG. ROSA. To FIG. 2 and FIG. 3, optical fiber current sensor (200) includes TOSA(Transmitter Optical Subassembly)(210), light splitters (beam splitter)(220), optical fiber sensor connectors (230) and ROSA(Receiver Optical Subassembly)(240). TOSA(210) Is an optical transmission operation and, packages for TO-CAN miniaturization, TOSA(210) a linear polarizer 1 corresponding to the polarizer of FIG. (212), and a wavelength retarder (214), linear polarizer (212) outputs light from the light source linearly and is mounted on, stems TO-CAN for (TO-CAN stem) miniaturization. The wavelength retarder (214) is integrally formed with TOSA(210) and reflects, linearly polarized light to a half wavelength or 1/4 wavelength, and the wavelength retarder (214) adjusts the vibration axis of the linear polarization to form TOSA(210) and (222) or 45 degrees of polarization with the polarized light separator -45. Light separator (220) has 50:50 separation ratios and separates linearly polarized light delayed by, wavelength retarder (214) to enter the sensor coil (300). The sensor coil (300) may be 1 reflective sensor coils as shown in FIG. (11) and may be formed of, reflective sensor coils, and the light incident on the optical fiber, may be reflected through the sensor coil. (10), and the light incident on the sensor coil is reflected while passing through the sensor coil, and the, sensor coil, (300). The reflected light is reflected by the light splitter (220) and enters ROSA(240). (220) May be positioned between the light splitter (300) and the sensor coil (220) so that light separated by the light splitter (300) may be accurately incident to the sensor coil (251), and a focal lens, may be positioned between the light splitter (300) and ROSA(240) so that the light reflected by (220) wavelength retarder ROSA(240) may be accurately incident to (252), and a focal lens, (214) may be positioned between (220) the light (253) splitter. (214). (220). At this time TOSA(210) and ROSA(240) may form a combined BOSA(Bidirectional Optical Subassembly), i.e. linear polarizer, wavelength retarder (212), polarization light splitter (214) reflective mirror (242), and photo diode (244) may be formed over one (PD1, PD2) stem, alternatively TO-CAN and, may form each, TOSA(210) OSA. ROSA(240). The fiber optic sensor connector (230) couples the optical fiber current sensor (200) to the sensor coil (300) to, and may be coupled to the sensor coil (300) for. BOSA and, when the optical fiber sensor connector (230) is coupled and detached. In FIG. 1, although the optical fiber sensor connector (230) is shown as a receptacle type, the optical fiber sensor connector (230) may have a pigle structure. ROSA(240), and. ROSA(240) may receive the light reflected by the light splitter (220) and, for TO-CAN miniaturization. , As shown in, and 3, ROSA(240) includes a polarizing light splitter 1 reflection mirror (32) corresponding to the photodetector (polarization beam splitter)(242), of FIG. (244) and a photodiode 1 corresponding to 2 photodetector (33) of FIG. (PD1, PD2). The polarization light splitter (242) and the reflection mirror (244) are mounted on TO-CAN stems (246) and the, polarized light separator (242) receives the light incident to ROSA(240) and separates the,axis direction from x and y, the polarized light splitter (242) outputs the light polarized in x-axis direction . y and the polarization direction of the light reflected by the 90 (PD1)-axis direction is 90 changed according to the polarization (244) of the two-polarized (PD2). light splitters. x. The photo diode (PD1, PD2) is mounted on TO-CAN stems (246) at a predetermined interval, detects light separated by, polarization and converts the detected light to a current value corresponding to an electric signal, and a partition, may be installed on (242) stems TO-CAN to minimize interference between separated lights along the polarization axis of the polarization light splitter (246). (cavity wall)(248). As such, optical fiber current sensor (200) can simplify TO-CAN structure by mounting optical elements such as linear polarizer (212) on (242), stem, polarization light splitter (244) reflection mirror (PD1, PD2) and photo diode, and thus can be manufactured at low cost and mass production. 4 Schematically illustrates a manufacturing method of 2 shown in FIG. ROSA. To FIG. 4, light incident to, ROSA(240) is separated according to the polarization axis of the polarized light splitter (242) and the polarizing beam splitter, and the reflection mirror (PD1, PD2) are fixed such that the (242) separated light is detected by the photodiode (244). and the polarizing beam splitter (242) and the reflection mirror (244) are combined to minimize an alignment error of the polarizing beam splitter TO-CAN and the reflective mirror (246). (249). The polarizing light splitters and the reflection mirror (242) are aligned on the (244) (244) stem TO-CAN, UV (246) using (242) epoxy. Attach. and partition (248) may be formed between the polarizing beam splitter (242) and the reflective mirror (244). 5 Is an output waveform . 500-2500 AT of an optical fiber current sensor measured while increasing the current to 500 AT by, as a graph illustrating output of an optical fiber current sensor according to an embodiment of the present invention. As shown in FIG. 5, it is found (200) that the output waveform of the two-fiber current sensor 60 Hz is well recovered as. AC signal. 6 Schematically illustrates another example of 2 shown in FIG. ROSA. To FIG. 6, ROSA(240') may further include 3 at ROSA(240) shown in FIG. TEC 9thermoelectric cooler)(243, 245). TEC(243, 245) Is positioned at one side of the polarizing light separator (242) and the reflection mirror (244) and absorbs a temperature around, polarized light separator (242) and the reflection mirror (244), and maintains the temperature of the polarizing light separator (242) and the reflection mirror (244) constant. The (polarization light separator, and the reflection mirror, maintain the ambient temperature of the polarizing light separator) and the reflection mirror, at . thereby preventing the polarization characteristics and the reflection characteristics from being changed by the ambient temperature of the polarizing beam splitter TEC(243, 245) (242) (242) and the reflection (244) mirror. (242) (244). (244). 7 Schematically illustrates an optical fiber current sensor according to an embodiment 2 of the present invention. To FIG. 7, optical fiber current sensor (700) includes OSA(710) and a wavelength retarder (720). OSA(700) May perform an optical transceiver operation and mounted on, single stem TO-CAN, such (730) may include a laser diode, light splitter OSA(700) polarized light splitter (LD), photo diodes (711), TEC(713, 714) and (712), (PD). The laser diode (LD) outputs, light as a light source. Light splitter (711) is the same as the function of the light splitter 2 of FIG. (220), a splitter (711) separates light from the laser diode (LD) to output a wavelength retarder (720), and separates light from the wavelength retarder (720) to output a polarized light splitter (712). The wavelength retarder (720) delays the light separated by the light splitter (711) at a half wavelength or 1/4 wavelength to enter the sensor coil (300), and the light reflected from, sensor coil (300) is delayed 1/4 wavelength or ¼ wavelength and output to the light splitter (711). The polarized light separator (712) separates the received light according to the polarization. The photo diode (PD) detects light separated by the polarization light splitter (242) and converts the detected light into a current value corresponding to an electric signal . and the partition TO-CAN may be installed on (730) stems (cavity wall)(740) to minimize interference between the transmitted and received lights. And TEC(713, 714) are located at one side of the light separator (711) and the polarization light separator (712) and absorb the ambient temperature of the, light separator (711) and the polarized light separator (712) to keep the temperature of the light separator (711) and the polarizing light separator (712) constant. By processing, optical transmission and the optical reception at one OSA, the structure of, optical fiber current sensors can be further simplified. Although the package type is described as TO-CAN, the optical fiber current sensor, may be formed in a package of another type. It is also possible. /And, may be implemented through a recording medium in which a program or a program for realizing a function corresponding to the configuration of an embodiment of the present invention is recorded or a recording medium in which the program is recorded, which can be easily implemented by those skilled in the art from the description of the present invention . It. is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. An optical fiber current sensor includes a transmitter optical subassembly (TOSA) that is formed in a package of a linear polarizer that applies light from a light source to a sensor coil that is formed with an optical fiber by linearly polarizing, a polarization beam splitter that separates light that is reflected from the sensor coil according to polarization, and a receiver optical subassembly (ROSA) that is formed in a package together with first and second photodetectors that detect separated light according to polarization. Erase Erase Erase Erase Erase Erase Erase Erase Erase Erase Erase Erase , The optical fiber current sensor, outputs the light to the sensor coil by delaying a wavelength of the light separated by the light splitter, and outputs the light to the light separator, and outputs the light to the sensor coil. The optical detector, outputs the light to the sensor coil and then outputs the light to the light separator by a light splitter, which separates the light reflected from the sensor coil, by the light separator, and outputs the light to the light separator. The optical fiber current sensor 13 of claim, further comprising at least one TEC maintaining the ambient temperature of the light separator and the polarized light separator. The optical fiber current sensor 14 of claim, wherein the package comprises the at least one TEC. The method 13 of claim. Optical fiber current sensor TO(transistor outline)-CAN including. package The light source of claim 13 wherein, the light source comprises a laser diode. The optical fiber current sensor 13 of claim, wherein 1/2 wavelength or 1/4 wavelength delay of the, input light is delayed.