• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.544-547
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• 2006

A time-domain modeling approach is used to study characteristics of a widely tunable coupled-ring reflector (CRR) laser diode(LD). The CRR consists of a bus waveguide and two coupled ring resonators coupled to the bus without resorting to distributed Bragg grating structure. The tuning range can be a few tens of nanometers with a side mode suppression ratio exceeding 35dB through the adjustment of currents into the phase control sections in the rings. The CRR laser diode has long effective cavity length compared to conventional laser diodes. Accordingly, a broad additional resonance peak in the amplitude modulation characteristics is observed between 20 to 30 GHz, implying the extension of amplitude modulation bandwidth.

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.102-103
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• 1999

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.272-273
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• 2000

대용량의 정보처리에 필요한 새로운 광원에 대한 연구가 활발히 진행되고 있는 가운데, 광원과 광변조 능력을 동시에 가지고 있는 VCSEL이 상당한 주목을 받아 왔지만, 이 소자는 발진하는 레이저의 파장이 활성층의 온도 변화에 따라 천이하는 점과, 편광의 변질 등으로 인해 8$\times$8이상의 고집적 어레이 제작이 어려운 단점이 있어 실용화에 어려움을 겪고 있다. 마이크로 디스크의 위스퍼링 갤러리 모드를 응용한 광양자테 (PQR) 레이저가$^{[l,2]}$ 지닌 몇 가지 특성들은 VCSEL이 가진 문제들을 해결할 수 있는 가능성을 제시하고 있다. 수 $\mu$A에서 nA급의 문턱전류로 구동할 수 있어 주입전류에 의한 활성층의 온도변화 통제가 가능하며, VCSEL이 온도가 증가에 따라 출력파장이 선형적으로 증가하는 반면, PQR 레이저의 출력 파장은 (equation omitted)에 비례하여 증가하므로 온도-파장 관계가 포화되는 영역에서는 주입전류나 외기 온도에 의한 영향을 거의 받지 않는 안정성 때문에 고집적 어레이 광원 제작시 유리하다. 또, 레이저 출력면의 각도에 따라 각각 다른 파장의 빛을 방출하므로, 각도에 따른 각 파장별 필터를 이용하면 광센서 등 여러 가지 용도에 응용할 수 있을 것으로 기대된다. (중략)

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.123-127
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• 2002

We have measured the wavelengths of the absorption lines of the $^{13}$ C$_2$H$_2$molecule by using a wavelength meter calibrated against the national optical frequency standard (iodine Stabilized He-Ne Laser, KRISS-R701) in the visible wavelength region. To measure the absolute wavelengths of the absorption lines, the frequency of the laser has been stabilized in the peaks and the sides of the absorption lines of $^{13}$ C$_2$H$_2$. Also, we have proposed the development of a frequency standard source of ITU-T grid using stabilization in the sides of the absorption lines of $^{13}$ C$_2$H$_2$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.4
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• pp.20-30
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• 1969

Several new modulators using Voltage Variable Capacitance Diode are discribed. It was investigated that amplitude modulation which does not need modulation power is obtained by mdulation VVC diode as a tuning element of the quartz oscillator circuit. It offers a good AM system for carryphones in the citizen bands. While frequency modulated quartz oscillators coupled with a quarter wave network were tested as a wide band frequency modulator, Hartley type transistor oscillator offers the most stable and reproducibel FM quartz oscillator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.271-274
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• 2007

본 연구는 $1.3{\mu}m$ 파장의 초고속 Nd:YAG레이저 펄스를 얻기 위해 AOM을 이용하여 모드록킹 Nd:YAG레이저 공진기를 구성하였다. 여기용 반도체 레이저는 중심파장 810nm, 출력 1.2W이며, 레이저 매질은 직경 3mm, 길이 10mm로 $Nd^{3+}$가 1.0at%로 도핑된 Nd:YAG Rod를 사용하였다. 모드록킹에는 음향광학 변조기(변조 주파수 40MHz)를 사용하여 펄스폭 ${\tau}p=80ps$의 극초단 펄스를 얻었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.926-929
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• 2005

Recently, laser interferometer is widely used as a measuring system in many fields because of its high resolution and its ability to measure a board area in real-time ail at once. In conventional laser interferometer, for examples Out of plane ESPI, In plane ESPI, Shearography and Holography, it uses PZT or other components as a phase shift instrumentation to extract 3-D deformation data, vibration mode and others. However, in most cases PZT has some disadvantages, which include noli-linear errors and limited time of use. In present study, a new type of laser interferometer using a laser diode(LD) is proposed. Using Laser Diode Sinusoidal Phase Modulating(LD-SPM) interferometer, the phase modulation can be directly modulated by controlling the LD injection current thereby eliminating the need for PZT components.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1216-1221
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• 2011

We propose a multiplexed fiber Bragg grating (FBG) sensor network for vessel monitoring to measure the variation of strain and temperature by environmental perturbation based on code division multiple access (CDMA). The center wavelength of FBG was linearly changed by environmental perturbation such as strain and temperature variation so that we could be monitoring the state of sensors. A RSOA was used as optical broadband source and which was modulated by using pseudo random binary sequence (PRBS) signal. The correlation peak of reflected signal from sensor networks was measured. In this paper, we used the sliding correlation techniques for high speed response and dynamic rage of sensors.

• ETRI Journal
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• v.9 no.2
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• pp.92-95
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• 1987

코우히어런트 광전송에 관한 연구의 현황을 간략히 기술하였다. 그 내용은 광원인 단일 주파수 레이저의 안정화 방법, 광의 변조 방식, 국부 발진광의 주파수 변환 방법, 평형 광검파 방법, 수신 광신호와 국부 발진광의 편극 상태를 정합시키는 기법 및 파장 분할 다중화 기술등이다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.43-52
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• 1999

We propose a new method for tuning of center wavelength in photorefractive filter using $LiNbO_3$ crystal doped with 0.015Wt.% Fe. through the filter bandwidth property analysis using the geometrical method, a new wavelength selectivity theory was presented. In this scheme, the tuning of the center wavelength can be achieved by the real time incident angle control of the received heam, which was gotten by the spatial light modulator. So, tuning time depend on the response time of the SLM and results in the high speed turing. Because the use of thermally fixed grating in our filter, it has uniform diffraction property to the all filtering wavelength. Designed tunable filter has 4nm bandwidth and composed of the three channel with 10nm space. From the optical experiment, we get the 4.5nm, 4.25nm, 4nm bandwidth and 1530.5nm, 1540.5nm, 1549.5nm center wavelength respectively.