• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.201-204
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• 1999

Polarization mode dispersion (PMD) restrict the bend-width of single mode optical filer, and it is important parameter in the optical fiber having long-length. Although fiber has perfect circular symmetry, fiber bending, twisting and laws governing manufacture cause additional Polarization mode dispersion. The effect of polarization mode dispersion in general single mode fiber of long length is discussed in this paper. Measurement of PMD with random mode coupling were conducted in two kind of fibers using different laws governing manufacture and interferometric method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.145-150
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• 2007

Optical communication according to request of technology of communications and optical fiber to be full filed faster communication and pass over transmission capacity limit per unit area, per unit hour appeared, and this optical fiber acts the biggest role to influence performance of optical communication network. Optical fiber(PMF Polarization Maintaining Fiber) is used, and is used by electric field measurement, self-discipline measurement, sensor(Sensor) Department by high definition measure such as thermometry and storehouse component that use because make broad sense status and polarized light information in passageway and union with storehouse integrated circuit etc. that use broad sense interference developing could transmit in state that keep transmitting broad sense plane of polarization is polarized light existence. Also, research is developed by optical fiber for Coherent communication recently.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.224-229
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• 2003

We realized a depolarizer based on two 2$\times$2 directional couplers and single mode optical fiber. A reduction method for the degree of polarization is demonstrated by using computer simulation, which is verified experimentally. The degree of polarization is -20 dB for the polarized input beam of spectral width less than 0.05 nm. The experimental results verify that the polarization noise, which is due to the change of the input polarization state, can be reduced by making the fiber-ring delay-line length greater thanthecoherencelengthofthesource.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.449-453
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• 2003

In a broadband erbium-doped fiber source for fiber optic gyroscope, a pump-polarization scrambling scheme is used to suppress the polarization dependence of the source mean wavelength. The degree of polarization of the pump is reduced to 1.4% by applying proper modulation depth to the polarization modulator where 10 m-long single-mode fiber is wound on a cylindrical PZT. In the case of using the pump-polarization scrambler as well as the output depolarizer, the mean-wavelength variations due to the random change of polarization are measured to be less than our measurement limit of 5 ppm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.11
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• pp.1509-1517
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• 1997

Charged and uncharged particle motions and collection characteristics around a bipolar charged rectangular shape electret fiber are studied numerically. Particle inertia, fluid drag, Coulomb force and polarization force are considered to predict the particle motion around the electret fiber. The effects of particle sizes, flow velocities, number of charges and polarities are also systematically investigated. For small size particles, the single fiber collection efficiency is greatly dependent on the charge polarity and the number of charges on a particle. However, particles larger than 5.mu.m do not show charging effect on collection efficiencies in the flow velocity ranges from 1.5 cm/s to 150 cm/s when the maximum charges are within +5 to -10. The results show that a strong electric field gradient at the corner of the bipolar charged fiber plays a very important role on collecting particles regardless of its charge polarity because of the polarization force. It also shows that the most penetrating particle size for a single electret fiber decreases as the flow velocity increases and the number of charges of a particle decreases.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1158-1165
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• 1988

In this paper, the polarization properties of spun fiber due to intrinsic birefringence and magneto-optic effects are theoretically analyzed and experimented. The degree of polarization which indicates the intrinsic birefrigence is measured over 0.818, and the variation of output polarization angle with input polarization angle is measured within 9$^{\circ}$. Compared with single mode fiber, spun fiber is found to have very excellent polarization-maintaining property. Implemented current measurement system using spun fiber can linearly measure the magnetic field up to 20,000 A/m generated by solenoid.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.716-721
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• 2016

A single-and dual-wavelength switchable polarized Yb-doped double-clad fiber laser around 1120 nm based on a pair of fiber Bragg gratings (FBGs) is demonstrated. The polarization-maintaining (PM) linear cavity is composed of a double clad PM Yb-doped fiber (YDF) and a pair of PM FBGs. The laser can operate in stable dual-wavelength or wavelength-switching modes due to the polarization hole burning (PHB) and the spatial hole burning (SHB) enhanced by the PM linear cavity. In dual-wavelength operation, the two orthogonally polarized wavelengths are centered at 1118.912 nm and 1119.152 nm, with an interval of 0.24 nm and a signal to noise ratio (SNR) of 35 dB. The maximum output power is 14.67 W when the launched LD pump is 24 W corresponding to an optical efficiency of 61.1%. The lasing lines switchover may be realized by adjusting the polarization controller (PC) fitted in the cavity. The two single-wavelengths are 1118.912 nm and 1119.152 nm. When the injected LD pump is 24 W, the highest output powers are 7.68 W and 8.64 W corresponding to optical efficiencies of 32% and 36% respectively. The spectral linewidth of the lasing lines are 0.075 nm and 0.07 nm, and the average numerical values of PER aredB and 19.9 dB, respectively.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.1
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• pp.31-39
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• 1991

The polarization properties of low birefringent optical fiber due to intrinsie birefringence and magnetooptic effects are theoretically analyzed and experimented. The low birefringent fiber is fo¬und to have more excellent polarization maintaining properties than normal single mode optical fiber. As the experimental results, the polarizability of low birefringent optical fiber is measured over 0.818. The variation of output polarization angle with input polarization angle is measured within $9^{\circ}$. Imple¬mented magnetic field measuring system using low birefringent optical fiber can linearly measure the magnetic field strength up to lOkAT generated by solenoid. The maximum error is 1.95% in the magnetic field strength of 4kAT.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.8-15
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• 2012

In this paper, we investigated possible optical parameters causing deviation of experimentally observed output spectra from theoretically predicted results in a high-order fiber comb filter based on a polarization-diversity loop configuration. They include wavelength dependency of half-wave plates (HWPs) inserted in the filter for wavelength switching and the modal birefringence of single-mode fibers (SMFs) with which optical components comprising the filter are connected. In order to consider the effect of the modal birefringence of the SMF on a filter performance, it is modeled as a low birefringence fiber with an arbitrary orientation angle and birefringence. It is found from the simulation results that the modal birefringence of SMFs strongly affects the spectral characteristics of the filter and decreases the extinction ratio of the filter, compared with the wavelength dependency of HWPs. In particular, it is also confirmed that the spectral deviation and asymmetric distortions of side-lobes in narrow band transmission spectra result mainly from the modal birefringence of SMFs.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2456-2458
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• 1999

The polarization mode dispersion (PMD) that restricts the transmission bandwidth was investigated in standard long single mode fiber which optimized at 1.3${\mu}m$. Although fiber has perfect circular symmetry, each optical fiber has different refractive index profiles. The investigation of PMD with random mode couplings were conducted in three kinds of fiber by the time-domain interferometric method. By using two manufacturing methods, MCVD(Modified Chemical Vapor Deposition) method and VAD(Vapor Phase Axial Deposition) method, the property of mechanical asymmetric lateral pressure, bending and twisting induced polarization mode dispersion were measured. The concatenated optical fibers were compared with other types.