• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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• pp.220-221
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• 2002

• 한국전기전자재료학회논문지
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• 제18권6호
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• pp.576-581
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• 2005

We fabricated red organic light emitting diodes(OLEDs) utilizing tis(8-hydroxyquinoline) aluminum $(Alq_3)$ doped with $5\%$ of (4-(dicyanomethylene)-2-i-propyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) (DCJTI) and investigated the driving and modulation characteristics for applying to the electro-optical conversion device. To improve the driving characteristics of red OLEDs, 3 V of offset voltage, which is equal to the turn on voltage, Is applied to the device. Offset voltage enhanced the optical EL output and reduced the rise time of EL waveforms of red OLEDs, and hence the cutoff frequency is increased with increasing applied voltage. The optical pulse of 100 MHz has been obtained from red OLEDs. Therefore, we confirmed that the red OLEDs can be applied to the fields of optical communication as an electro-optical conversion device.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.33-38
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• 2002

An optical single cylinder diesel engine equipped with a common-rail injection system has been built to investigate diesel combustion and emission characteristics. Three optical widows (piston crown quartz for bottom view of the cylinder, upper piston quartz for allowing laser sheet and liner quartz for side view) have been placed in the optical engine to visualize spray characteristics and combustion process inside the cylinder. Before doing further research using various optical diagnostics with the optical engine, fundamental combustion experiments and flame visualization incorporating a high speed motion analyser have been carried out with a wide range of engine operating conditions.

• 한국생산제조학회지
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• 제23권2호
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• pp.133-137
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• 2014

The recent development of electro-optic devices and anticorrosion media has made it necessary investigate infrared optical systems with solid-solid interfaces of materials with amorphous characteristics. One of the most promising classes of materials for these purposes seems to be chalcogenide glasses, which are based on the Ge_Sb_Se system, have drawn much attention because of their use in preparing optical lenses and fibers that are transparent in the range of 3-12 um. In this study, a standard melt-quenching technique was used to prepare amorphous Ge_Sb_Sechalcogenideto be used in the design and manufacture of infrared optical products. The results of structural, optical, and surface roughness analyses of high purity Ge_Sb_Sechalcogenide glasses after various annealing processes reported.

• Current Optics and Photonics
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• 제3권5호
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• pp.429-437
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• 2019

Temperature adaptability is an important metric for evaluating the performance of an optical system. The temperature characteristics of the optical system are closely related to the material and shape of its lens. In this paper, we establish a mathematical model relating the temperature characteristics to the shape and material of the lens. Then a novel assembly structure that can solve the lens constraint and positioning problem is proposed. From those basics, the correctness of the theoretical model and the effectiveness of the assembly structure are verified through simulated analysis of the imaging quality of the optical system, whose operating temperature range is $-60{\sim}100^{\circ}C$.

• 대한전자공학회논문지
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• 제26권11호
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• pp.1736-1742
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• 1989

In this thesis, to verify input-output characteristics of GaAs MESFET, light is illuminated to C-band oscillator which already designed and manufactured, thus input-output variation of GaAs MESFET is to be shown. Experimental results of two kinds of optical effects, optical tuning and opticla switching, of GaAs MESFET Oscillators are presented. For optical tuning, the Oscillation frequency decreases with optical illumination and the Oscillator power output generally increases with optical illumination, the increase being around 1 to 3 dBm at 1mW/mm\ulcornerlight intensity. While the DC-lingt illuminated Oscillator response data provide information of the optical senditivity of GaAs-MESFET Oscillators. Pulse-light illuminated transient response data can be invoked to understand the detailed optical-electrical interaction mechanisms response. Thus, it is shown that direct control of micro-devices is realisable, if we use optical effect of GaAs semiconductor compound.

• 한국정밀공학회지
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• 제23권5호
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• pp.103-110
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• 2006

Automatic optical alignment modules are a key technology in optical communication system. However, the optic component assembly depends highly on manual or semi-automated alignment process. In this paper, a novel alignment mechanism with minimum degree-of-freedom has been designed and theoretical models are derived from geometric optical characteristics on collimators, optical filters and optical ray alignment. The automatic alignment control algorithm has been newly developed based on the mechanism and models, and then we make fast, precise and reliable alignment through the algorithm. The reliability of developed modules has been verified with various simulations and performance evaluations.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.272-273
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• 2004

Optical connector is prone to take environment attack since it is exposed to various environmental conditions. As the data bit rate is increased in the modern optical communication system. the stability of optical connector becomes more important issue in complex network comprising of many connection by connectors. In this research, to estimate the influence of defects of connector, especially surface scratches, on the transmission, surface scratches were intentionally introduced on the cross sectional surface of optical connector and the insertion loss, return loss. and BER were measured as functions of geometry and density of scratches, Environmental conditioning was also performed onto these connectors and the variations of basic optical characteristics mentioned above were measured. Based on this measurement the lifetime of connectors was estimated by statistical prediction method.

• 한국광학회지
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• 제33권1호
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• pp.35-44
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• 2022

광학계는 매우 다양한 용도로 사용되고 있기 때문에 유사한 구성의 광학계에서도 활용목적과 주어진 광학사양에 따라 다양한 설계가 존재한다. 하지만 광학수차는 광학계의 구조와 광학사양 모두에 영향을 받으므로 수차분석만으로는 광학설계의 고유한 특성을 파악하기 어렵다. 이 연구에서는 무차원의 설계변수를 사용하여 광학사양과 무관하게 광학설계의 수차특성을 파악하는 방법을 연구하고, 예시로서 서로 다른 용도와 사양을 가지는 4종의 triplet 설계를 분석하였다.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.147-151
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• 2004

In this study, an optical fiber assembly directly coupled with a laser diode or a photo diode is designed to confirm high reliable optical coupling efficiency of optical transmitter(Tx) and receiver(Rx). The optical fiber assembly is fabricated by soldering an optical fiber and a Kovar ferrule using a glass solder after inserting an optical fiber through a Kovar ferrule. The Kovar which has good welding characteristics is applied to introduce laser welding technique. The glass solder has excellent thermal characteristics such as thermal shift delamination compared with PbSn, AuSn solder previously used usually. Furthermore, the glass solder doesn't need fiber metalization and this enables low cost fabrication. However, the glass soldering is high temperature process over 35$0^{\circ}C$ and the convex shape after solidification due to surface tension causes the stress concentration on optical fiber. The stress concentration on the optical fiber increases the optical insertion loss and possibility of crack formation. The shape of glass solder was designed referring to 2-D Axi-symmetric FEM simulation. To test the mechanical reliability, mechanical vibration test and shock test were done according to Telcorida GR-468-Core protocol. After each test, the optical loss of the stress distributed fiber assembly didn't exceed 0.5 dB, which passes the test.