• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.6
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• pp.75-81
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• 1995

InGaAsP/InP uncooled LDs emitting at 1.3$\mu$m wavelength are of interest for several application of fiber-to-the-home, optical interconnection, long-haul high-bit-rate optical transmission systems, etc. The strain compensated PBH-MQW-LD employing 1.4% compressive strained well (${\lambda}=1.3{\mu}m$) and 0.7% tensile strained barrier (${\lambda}=1.12{\mu}m$) layers grown by low pressure metallicorganic vapor phase epitaxy was found to be low threshold current and stable temperature characteristics. The average threshold current of 5.6mA and average slope efficiency of 0.27mW/mA at room temperature were obtained for uncoated uncooled-LD.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.8-13
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• 2008

At present many research projects on high-speed spindles are being conducted. These projects require a measurement technique which includes heat expansion, vibration and displacement measurement according to angular velocity. This paper presents the development of a measurement system for high-speed spindle displacement. The measurement system is based on $LabView^{(R)}$ and features the following sensors: optical sensor which reacts to the position of a marker on the spindle and enables two Laser Displacement Sensors(LDS). These Laser Displacement Sensors send their data to a DAQ(Data Acquisition Device). It is important that the delay time caused by the response times of the sensors as well as the sampling rate of the DAQ is considered because the spindle revolves at very high speeds.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1200-1203
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• 1990

Recently, the CAD/CAM system to automatically design and process are used in almost every industry world. We designed an original digitizer system to digitize a real size car drawing. We succeeded in the development of super large size Laser Digitizer System (LDS) which has input area of 2m by 6m, resolution of 0.1mm and accuracy of .+-.0.5mm. This Laser Digitizer System can use in design of cars, ships, planes and big maps. Also can use in sensing the position of nozzle head of laser processing system, and so on.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.161.1-161
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• 2000

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.103-104
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• 1998

GaN is a ppromising materials fot applications in the blue/ultraviolet (UV) light emitting diodes (LEDs)[1] and laser diodes (LDs) [2] High quality ohmic contacts are very critical to these applications since the qualities of ohmic contact system pplay an impportant roles in the high efficient device opperations. For the n-GaN there have been many repports about ohmic contacts and the sppecific contact resistance were as low as from 10-8$\Omega$cm2 However for the ohmic contacts on pp-GaN much fewer study were repported and the sppecific contact resistivity was much lower than of n-GaN. In this ppapper we repport a new Ni/ppt/Au metallization scheme and discuss the mechanism of ohmic formation

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.73-80
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• 1995

We fabricated the 1.55.mu.m RWG-DFB-LD and measured its electrical and optical characteristics. Interference fringe of optical beams was used for grating formation and epi layers were grown by lower-temperature LPE. The fabricated RWG-DFB-LD operated in a single longitudinal mode with more than 30dB SMSR at 1543nm emitting wavelength and its threshold current was 40mA. The wavelength shift with operating temperature and characteristic temperature T$_{o}$ were 0.9${\AA}/^{\circ}C$ and 59K, respectively. Linewidth enhancement factor .alpha. and linewidty.optical power product were estimated as 6.15 and 60MHz$\cdot$mW respectively.

• Journal of the Optical Society of Korea
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• v.9 no.2
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• pp.45-48
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• 2005

We investigate effects of the injected ASE (Amplified spontaneous emission) bandwidth on the performance of the wavelength-locked Fabry-Perot laser diodes (F-P LDs) under constant injection power density and constant injection power. For the constant injection power density, we can determine the minimum injection bandwidth by the required intensity noise or the bit-error rate (BER) performance. On the other hand, there exists the optimal ASE bandwidth for the constant injection power to minimize the intensity noise.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.101-106
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• 2012

We demonstrate a cost effective broadcast signal transmission at 1.25-Gb/s with 100 GHz channel spacing based on a broadband light source (BLS) for a wavelength division multiplexing-passive optical network (WDM-PON). The BLS is implemented by using mutually injected Fabry-Perot laser diodes (MI F-P LDs). The error-free transmission without a forward error correction (FEC) is achieved by its low relative intensity noise (RIN). The number of usable modes is determined by RIN and/or extinction ratio (ER) in the spectrum sliced light output.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.386-391
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• 2009

PSPICE circuit parameters of the blue laser diodes grown on wurtzite AlGaInN multiple quantum well structures were extracted directly from the three level rate equations. The relevant optical gain parameters were separately calculated from the self-consistent multiband Hamiltonian. The resulting equivalent circuit model for a blue laser diode was schematically presented, and its modulation characteristics, including the pulse response and the frequency response, have been demonstrated by using a conventional PSPICE.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.698-703
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• 2016

We report a new all-optical flip-flop (AOFF) with a quite simple structure, using optical beating in an injection-locked Fabry-Perot laser diode (FP-LD) with optical bistability. While conventional AOFF methods using an injection-locked FP-LD require additional devices such as secondary FP-LDs or polarization controllers for reset operation, the proposed method can be implemented using only a single commercially available FP-LD with set and reset signals. The optical beating induces intensity fluctuations inside the FP-LD, and releases the locking state to the reset state. Even though we demonstrated the AOFF at 100 Mbit/s, we expect that its operation rate could extend to 10 Gbit/s, according to the limit of the FP-LD's frequency response.