• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.1
• /
• pp.123-128
• /
• 2010

We have investigated the properties of the novel triangular ring resonator with the total internal reflection mirrors and the semiconductor optical amplifier for photonic integrated circuits (PIC). A novel triangular resonators containing active and passive sections are fabricated and characterized with various multimode interference (MMI) lengths. The optimum MMI length and width turn out to be 108 and 9 ${\mu}m$, respectively. A free spectral range of approximately 228 GHz is observed near 1558 nm along with an on-off ratio of 9 dB. The proposed triangular resonator has a good advantage to remove the direct coupling between the two access waveguides of the MMI coupler. Hence, such resonators can be directly integrated with other devices making compact and highly functional PIC possible.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.415-419
• /
• 1999

Many bipolar logic circuit of conventional occurred problem of speed delay according to deep saturation state of vertical NPN Transistor. In order to remove minority carries of the base region at changing signal in conventional bipolar logic circuit, we made transistor which is composed of NPN transistor shortened buried layer under the Base region, PNP transistor which is merged in base, epi layer and substrate. Also the Ring-Oscillator for measuring transmission time-delay per gate was designed as well. The structure of Gate consists of the vertical NPN Transistor, substrate and Merged PNP Transistor. In the result, we fount that tarriers which are coming into intrinsic Base from Emitter and the portion of edge are relatively a lot, so those make Base currents a lot and Gain is low with a few of collector currents because of cutting the buried layer of collector of conventional junction area. Merged PNP Transistor's currents are low because Base width is wide and the difference of Emitter's density and Base's density is small. we get amplitude of logic voltage of 200mv, the minimum of transmission delay-time of 211nS, and the minimum of transmission delay-time per gate of 7.26nS in AC characteristic output of Ring-Oscillator connected Gate.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1800-1802
• /
• 1998

The Pohang Light Source (PLS) is a third generation 2 GeV synchrotron machine. An injection kicker modulator is positioned in the PLS storage ring tunnel. The kicker modulator is driving four kicker magnets simultaneously. The kicker magnets produce magnetic field to deflect the stored beam orbit in the storage ring closer to the injected beam from the PLS beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. The current kicker modulator was upgraded and installed on August 1995. Since then, the kicker modulator has shown very reliable and stable performance. The kicker modulator specifications are ${\sim}6.0{\mu}s$ full width, ${\sim}24$ kA peak current, and 10 Hz repetition rate. Output current waveform is a half sinusoid. Two thyratron switches(EEV CX-1536AX) are used in the kicker modulator. Total accumulated thyratron heater run hour is about 15,000 hours as of May 1998. Measurement result of spatial magnetic field distribution in the kicker magnet shows good uniformity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.10a
• /
• pp.766-767
• /
• 2010

By using LED which is a light source which has been in the spotlight recently, the ring light for medical purposes was developed for shadowless shooting of local site in the affected area. The developed ring light was designed to be able to control the various quantity of light by using PWM (pulse width modulation) method, and by controlling each LED (light emitting diode) independently the regulation of color temperature and color rendering are possible. Also, the persistent light for continuous shooting of affected area and flash mode action for snap shooting are possible. In this study the response speed of momentary flash function was checked using interface circuit configured for momentary shadowless shooting of affected area.

• ETRI Journal
• /
• v.25 no.3
• /
• pp.195-202
• /
• 2003

This paper proposes a new LDMOSFET structure with a trenched sinker for high-power RF amplifiers. Using a low-temperature, deep-trench technology, we succeeded in drastically shrinking the sinker area to one-third the size of the conventional diffusion-type structure. The RF performance of the proposed device with a channel width of 5 mm showed a small signal gain of 16.5 dB and a maximum peak power of 32 dBm with a power-added efficiency of 25% at 2 GHz. Furthermore, the trench sinker, which was applied to the guard ring to suppress coupling between inductors, showed an excellent blocking performance below -40 dB at a frequency of up to 20 GHz. These results confirm that the proposed trenched sinker should be an effective technology both as a compact sinker for RF power devices and as a guard ring against coupling.

• Korean Journal of Optics and Photonics
• /
• v.10 no.1
• /
• pp.58-63
• /
• 1999

A 10 GHz harmonically mode-locked semiconductor-fiber ring laser was implemented using a semiconductor optical amplifier at $1.5\mu\textrm{m}$ The laser pulse has 13~18 ps pulse duration, 0.4~0.6 nm spectral width and was positively chirped. The output pulse with an average power of 4 dBm was compressed to 6.8 ps using 2 km long standard single mode optical fiber.

• Textile Coloration and Finishing
• /
• v.13 no.6
• /
• pp.428-434
• /
• 2001

This study surveys the fiber behavior in yam formation and the Physical properties of Solo-spun yarn. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier In the previous part, the physical properties such as yarn count, evenness, strength, and breaking elongation of these yams were compared with the properties of ring shun yarns and analysed with the mechanism of Solo-spun yarn formation. In the second part of this report, the abrasion resistance and hairiness were discussed wish respect to the micro yarn structures. The narrower the groove width of Solo-spun roller is, the more active the bulk fibers migration is. The Solo-spun film structure has two groups. One is shorter than the others one in longitudinal direction of yarn and has the same structure as ring-spun yarn, which is derided from the smooth zone on the surface of Solo-spun roller. The other one is longer than the former and there are the wrapping fibers. This part is derived from the conflicted grooves on the surface of Solo-spun troller.

• Textile Coloration and Finishing
• /
• v.13 no.6
• /
• pp.70-70
• /
• 2001

This study surveys the fiber behavior in yarn formation and the Physical properties of Solo-spun yarn. The specimens were made by six types of Solo-spun rollers with fixed twist multiplier In the previous part, the physical properties such as yarn count, evenness, strength, and breaking elongation of these yarns were compared with the properties of ring spun yarns and analysed with the mechanism of Solo-spun yarn formation. In the second part of this report, the abrasion resistance and hairiness were discussed with respect to the micro yarn structures. The narrower the groove width of Solo-spun roller is, the more active the bulk fiber migration is. The Solo-spun yarn structure has two groups. One is shorter than the other one in longitudinal direction of yarn and has the same structure as ring-spun yarn, which is derived from the smooth zone on the surface of Solo-spun roller. The other one is longer than the former and there are the wrapping fibers. This part is derived from the conflicted grooves on the surface of Solo-spun roller.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.11 no.5
• /
• pp.307-314
• /
• 1986

Propagation constants for TMon and TEon modes in a circular waveguide with a ring type dielectri are computed using the numerical analysis when the width of dielectric is varied regularly. This structure can be applied to the supporter to make improve the Q-factor of dielectric resonators, and the results of numerical calculation can be used to design the slow wave structures. Also, the numerical analysis in this paper can be used to determine the resonant frequencies in dielectric resonators.

• Korean Journal of Optics and Photonics
• /
• v.8 no.6
• /
• pp.456-460
• /
• 1997

Several methods of aligning ring type cavities have been investigated for long time. The measurement of cavity transmission spectrum control is somewhat effective due to aligning cavity with measuring cavity loss at the same time. In this research, four mirrors are aligned and attached by the measurement of pulse width of the transmitted light. The intracavity loss is optimized to about 0.98%, giving the calculated total reflection coefficient of about 99.02%.