• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.106-112
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• 1994

The injection-locking of the broad-area diode laser was analysed by using the Fabry-Perot model. The far-field pattern of the output beam was able to be treated by superposing the individual beams emitted from the front facet due to the multiple reflections between the front and rear facets. and the exact near and far field patterns were obtained. The angle-steering effect according to change of the incident frequency was changed was calculated and found to be 0.022 degree/GHz with a bandwidth of 120 GHz.20 GHz.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.2
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• pp.10-14
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• 1980

In this paper, the second harmonic distortion of the DH L.D. is analyzed using dynamic and static rate equations. In this analysis the modulation current Jm is changed by varang the iinjection current with the relation of where m stands for modulation index. It is showed that relative harmonic distortion ( ) has a peak exactly at the threshold current. It is also confirmed that this method is simople and more accurate than previously reported methods in the decision of the threshold current.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.6
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• pp.72-77
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• 1980

We analyze several problems concerning the operation of the optical feedback prebias control scheme in the loser diode optical transmitter and present a LD simulation circuit as a way of adjusting the component's optimum value without using the Laser - triode. 1.5% light power decrease was observed between the temperature range of $0^{\circ}C$ and 36$^{\circ}C$ in which the total light power of LD was used for feedback loop and fairly good operation was demonstrated when a star coupler was employed as a beamsplitter by which approximately 1% portion of the light power was feedbacked.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.76-77
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• 1998

In this paper, the authors have implemented a blood flow simulator and a blood flowmeter probe using self-mixing effect of the laser diode. The purpose of the blood simulator is to simulate microvascular blood flow in tissue. It consists of melinex film (thickness = $125{\mu}m$) which has similar optical characteristics to epidermis and porous polyethylene filter (Vyon, porosity 35%, mean pore size $50{\mu}m$, thickness=1 mm) which has similar optical characteristics to dermis. The blood flowmeter probe consists of laser diode(5 mW, 780 nm wavelength), CD lens(focal lenght 12 mm), current-to-voltage converter, highpass filter, and preamplifier. It doesn't need optical fiber, therefore, implementation of the probe is simpler than conventional probe using optical fiber.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.53-57
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• 2011

We developed a small methane detection system because methane gas is used in many areas and is dangerous. The developed system consisted of LD(Laser Diode) tuned a wavelength of $1.65\;{\mu}m$, two mirrors to collect a laser beam, photo detector. It could detect methane gas at a long range and its sensitivity was 1.98 V/$CH_4%$.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.9-12
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• 2001

Optical aligning process to archive the maximum optical coupling is crucial in many optical device manufacturing line such as laser diode module. Due to the three-dimensional nature of housing module and the aligning process for laser diode coupler, large amount of the manufacturing time, typically ranging from tens of minutes to an hour has to be devoted to the aligning process alone. In this thesis, we propose a new optical aligning process that employee a two-pass algorithm: coarse-to-fine search. Coarse search is a kind of blind search that finds the candidate region where the maximum optical coupling might mostly occur, followed by a fine searching that finds the maximum within the candidate region. The algorithm has been tested on 50 samples of cam-type laser diode modules, and the experimental results are analyzed in terms of aligning time and coupling efficiency.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.126-129
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• 2002

To extract exact screening conditions of TO-CAN laser diode, junction temperature during screening was investigated. Temperature increase due to thermal resistance was measured and compared with theoretical calculation. Injection current dependence of injection temperature was derived with good agreement with experimental data and used to obtain accurate screening conditions.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.359-363
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• 2008

A novel WDM-PON system delivering bidirectional 1.25-Gbps data and broadcasting data is proposed. A subcarrier signal modulates optical carriers of a Fabry-Perot-laser-diode based broadband light source to broadcast to all users. Reflective semiconductor optical amplifiers are used as modulators for the baseband data at both the optical line terminal and the remote optical network unit for a channel. Bit error rate and error vector magnitude were measured to demonstrate the proposed scheme.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3016-3018
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• 2005

The PSD(Position Sensitive Detector) is a sensor for detecting the position of incident light. Because of its various advantages, it is used for position and angle sensing, optical range finders, laser displacement sensing, and etc. In the previous study of the position finding system, the laser tracking robot is developed. Small data rate and unidirectionality is the characteristics of data communication both DSP-based pan/tilt control board and the robot. If we can transmit data to the target using PSD sensor and laser diode module, there is no need for communication devices such as the bluetooth and wireless module. For this reason, this paper presents the new method for data transmission. Transmit data using RS-232 is modulated by a VTF(Voltage To Frequency) converter The laser diode module transmits the modulated data. And then the PSD sensor receive that data. Demodulation process is accomplished by the system which is consisted with trans-impedance amplifier, FTV(Frequency To Voltage) converter, and etc.