• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.204-205
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• 2003

We demonstrate a novel OFDR system with compactness and short measurement time based on the use of a wavelength-swept mode-locked fiber laser. The optical source uses an intra-cavity tunable Fabry-Perot filter as a tuning element. The fiber laser sweeps 20 nm in less than 10 ms. Spatial resolution of 100 fm and total measurement range of several centimeters are demonstrate

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1030-1035
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• 1992

This paper presents a non-contact type displacement sensor designed based on optical triangulation method. The optical principles of the sensor are described in detail with aids of paraxial geometric optics. A prototype sensor is designed and fabricated by using modern optoelectronic hardware. Its measuring performances are evaluated and discussed through a series of calibration processes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1649-1657
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• 2006

Fizeau interferometer is well known optical instrument for measuring the lens profile accurately. The object of this study is focused on the design and optical measuring techniques for large optical components, such as a reflection mirror for astronomical purpose. Measuring of large optical lens, the object could not be moved as small one but the measuring instrument must be moved for the alignment, because of the geometric conditions and the accuracy of the stage. Therefore, a five axis stage is designed to align the Interferometer instead of the measuring object. This instrument will be used for an on machine measuring system in polishing machine for large optical lens.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.1
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• pp.47-53
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• 1999

CD-ROM(Compact Disk-Read Only Memory) is very attractive storage media because it has much storage space but is small size and portable. Optical pickup, one of the most important parts for reading data on a CD-ROM, is not produced tuned up. For the use of goods, we must tune up the optical pickup by adjusting the screw for adjustment. First, we developed analog servo system for optical pickup tuners. For eliminating some problems in analog servo system, this paper designed the modeling of digital servo system for optical pickup tuner. Though the characteristics of optical pickup are changed, the digital servo system for optical pickup tuner can easily apply to all pickup, and can reduce the measurement error among the optical pickup tuners. For the purpose of confirming the designed digital servo system, we produced data that specify the disk vibration and the disk eccentricity, and simulated servo system with MATLAB.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.209-216
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• 2010

Optical Temperature Distribution Sensor Measurement System uses fiber optic sensors itself for temperature measurement is a system which can be measured the Installed surrounding entire temperature as a thousand points by laying a single strand of fiber optic. If there are a lot of measuring points in the distribution Measurement, the cost of each measuring point can be reduced the cost level of existing sensors and at the same time this has the advantage of connecting all sensors as one or two strands of fiber. Generally Optical Fiber is used for communication but Optical Fiber itself can be used for sensor and it has the characteristic of sensor function which can be measured Temperature in the at least each one meter distance. By using these characteristics each sensor and the number of Connection Lines can be reduced. In this paper, we implement a real time temperature monitoring system, which is easy to manage and control for data storage, data management, data storage using a computer and which has the functions of monitoring and correction according to Real-time temperature changes using historical temperature data.

• Current Optics and Photonics
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• v.4 no.3
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• pp.229-237
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• 2020

In this study, a beam-coupling system is designed to improve the coupling efficiency of achip-integrated spectrometer when the waveguide is arranged in a linear and discrete manner. In the proposed system the beam is shaped to be anti-Gaussian, to deposit adequate energy in the edge waveguides. The beam is discretely coupled to the corresponding waveguide by a microlens array, to improve the coupling efficiency, and is compressed by a toroidal lens to match the linear discrete waveguides. Based on the findings of this study, the coupling efficiency of the spectrometer is shown to increase by a factor of 2.57. Accordingly, this study provides a reference basis for the improvement of the coupling efficiency of other similar spectrometers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.203-206
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• 2001

This paper presents a straightness measurement system for flat and long workpieces. The measurement system consists of a laser optical unit, a CCD camera and processing system, and a carrier system with a stylus. The carrier system accompanies the stylus, which displaces a retroreflector along the surface profile. The optical unit is used to optically amplify the displacement of retroreflector. The CCD camera and processing system finally identifies the vertical displacement of the stylus unit. The developed system is applied to two surfaces: ground surface and LM guide surface. The experimental results show that the developed system can measure the straightness of flat surfaces within sub-micron error.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.83-86
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• 2002

In this paper, Efficiency of fiber optical system which consist of optical sensor and program was estimated According to the test results, the accuracy of sun-tracking was the most important of performance of the system.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.10
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• pp.845-850
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• 2016

A direct laser lithography system is widely used to fabricate various types of DOEs (Diffractive Optical Elements) including lenses made as CGH (Computer Generated Hologram). However, a parametric study that uniformly and precisely fabricates the diffractive patterns on a large area (up to $200mm{\times}200mm$) has not yet been reported. In this paper, four parameters (Focal Position Error, Intensity Variation of the Lithographic Beam, Patterning Speed, and Etching Time) were considered for stabilization of the direct laser lithography system, and the experimental results were presented.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.420-425
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• 1997

An interaction-free measurement system with the polarization-based Mach-Zehnder interferometer structure is described. Properties of the system are investigated especially for nonopaque objects. Here it is shown that the interaction-free measurement of such objects is possible. Our system, whose detection efficiency corresponds to 70% in the sense of interaction-free measurement, was implemented and preliminary experiments were performed to show its feasibility.