• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.217-222
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• 2009

In this paper, a low-cost hybrid-integrated tunable laser is realized using a polymer-ring resonator-based add/drop filter reflector and a reflective semiconductor optical amplifier. The add/drop filter reflector, composed of a double-ring resonator with different radii, can have characteristics of selective wavelength reflection and wide wavelength tuning with an aid of vernier effect derived from the radii difference. By hybrid-integrating the reflective semiconductor optical amplifier with the add/drop filter reflector, a tunable laser can be realized through an active alignment method. The hybrid laser exhibited a single mode lasing with side mode suppression ratio of 26 dB and full width half maximum of 0.03 nm. In addition, applying a low current as small as 25 mA onto electrodes over add/drop filter reflector, a wavelength tuning range of 17 nm could be obtained.

• Korean Journal of Optics and Photonics
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• v.11 no.6
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• pp.429-433
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• 2000

A study of the tunable fiber DFB laser using PZT-stretcher is presented. The device has an laser ocsillator by using a fiber Bragg grating at 1559.4 nm written directly into a 3-cm long $Er^{3+}$ doped fiber. Post UV-exposure method to provide the necessary phase shift is used for a single mode operation. The device shows the single mode operation of $230\muW$ output power and has a narrow linewidth of 35 kHz. The lasing wavelength of the laser can be tuned in a range of 3 nm by stretching the grating.rating.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.10 s.340
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• pp.19-28
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• 2005

In this paper, we analyzed tuning characteristics of the widely tunable SGDFB laser diode integrated with SGDBR. The improved time-domain model is used to analyse the laser diode. From the numerical analysis, the length of phase control region in the SGDFB section influences on the output power and the tuning range. Also, it was confirmed that the tuning range is affected by the length of the laser diode, the residual reflectivity at the facet, and the position of the facet.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.235-238
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• 2008

In this paper, we have developed wavelength swept laser system for the swept source optical coherence tomography(SS-OCT). A laser is constructed by using the two SOAs parallel configuration, fiber Fabry-Perot tunable filter(FFP-TF). The wavelength sweeps are repetitively generated with the repetition period of 50Hz. The wavelength tuning range of the laser is more than FWHM of 80nm centered at the wavelength of 1310nm and the line-width of the source is 0.12 nm.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.242-243
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• 2000

매우 짧고 결맞는 극자외선 광원의 개발에 대한 기대로 강력한 레이저 장과 상호작용하는 원자에서 일어나는 비선형 다광자 현상에 대한 연구가 최근에 활발하게 전개되고 있다. 이 상호작용 과정에서 발생하는 빛은 매우 넓은 파장 영역에 걸쳐있으며, 입사 레이저의 홀수 배에 해당하는 매우 높은 차수의 조화파들을 포함하고 있다고 알려져 있다$^{(1,2)}$ . 최근의 이론 및 실험에 의하면, 강력하고 짧은 레이저 펄스를 사용하면 고차조화파의 파장에 청색변이를 일으킬 수 있다$^{(3.4.5)}$ . 실제 관측된 청색변이는 이웃하는 홀수 조화파의 간격보다 더 크다$^{(5)}$ . 따라서, 원리적으로는 매우 넓은 가변 폭을 갖고 연속적으로 파장을 조정할 수 있는 파장가변 극자외선 광원의 개발이 가능하다. (중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.117-117
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• 2013

레이저 레이더용 시력안전파장대 고출력 광펄스 생성을 위한 광원으로 MOPA 구도로 광섬유 레이저를 제작 하였다. MOPA 기반 펄스 광섬유 레이저는시력 안정 파장대인 1,550 nm 대역 파장을 갖고 펄스폭이 2 ns 이하이며 반복률이 30~240 kHz 가변 가능하다. 광섬유 증폭단에서 1단 증폭기는 저잡음용 코어 펌핑 방식의 증폭기로 구현하였으며, 2단 증폭기는 중출력 증폭기로 코어 펌핑구조에 후방향 펌핑 구도로 설계하였다. 3단 증폭기는 최종목표인 2ns 이하의 펄스 폭 및 25 kWp 이상의 첨두출력을 달성하기 위하여 클래딩 펌핑 방식의 고출력 광증폭기로 구현하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.55-60
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• 2008

Multi-wavelength Erbium-doped fiber(EDF) ring laser was developed by using a sampled fiber Bragg grating reflecting multiple wavelengths, which was formed by impressing periodical pressure on the outside of a fiber Bragg grating. The wavelength spacing was varied to 4.1nm, 1.41nm and 0.82nm, by pressing the grating with the pressure period $200{\mu}m$, $580{\mu}m$ and $1000{\mu}m$, respectively.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.257-262
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• 2001

A Littman type tunable external-cavity diode laser system was developed. The laser output which is the Oth-order diffracted beam from a diffraction grating in an external cavity is a single longitudinal mode. Its FWHM was measured as less than 9 MHz. With the diode driving current of 140 mA and operating temperature of $25^{\circ}C$, the coarse tuning range of 3.475 urn was measured. A fine tuning experiment in which an external mirror was rotated by a PZT driven by a sawtooth wave was performed, and its tuning range of 0.042 urn was measured. sured.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.228-229
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• 2002

강한 세기의 레이저가 원자에 입사하여, 조사된 레이저 파장의 홀수 배에 해당하는 파장을 가진 빛이 여러 차수에 걸쳐 발생하는 것을 고차조화파(high-order harmonics)라고 한다. (1.2) 고차조화파를 이용하면 고가의 방사광 가속기로 발생시키는 연엑스선 영역의 빛을 작은 비용과 작은 규모의 장비로 발생시킬 수 있으므로 많은 주목을 받고 있다. 고차조화파는 기본적으로 원자의 공간적인 대칭성과 레이저 전기장의 시간적 주기성에 의해 홀수 차수에서 발생하게 된다. (중략)

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.321-326
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• 2003

We constructed grating- tuned external cavity semiconductor lasers using Littman and Littrow configuration, for which the wavelengths are tuned by rotation of the grating. This wavelength tunable semiconductor laser is one of the main devices of WDM optical communication. In Littman configuration, the wavelength range of about 60 nm (The C- and L-band range of 1,530~1,590 nm) was obtained by changing the incidence angle of the grating about $\pm$1$^{\circ}$ from the incidence angle of 70$^{\circ}$. In the 40 nm tuning range, the output power variation was less than 1.25 ㏈ and the side mode suppression ratio(SMSR) was 32 ㏈. In Littrow configuration (The incidence angle and the first order diffraction angle is the same, i.e. $\alpha$=$\delta$), the wavelength tuning range was about 80 nm for the same conditions used in Littman configuration except the incidence angle ($\alpha$=49$^{\circ}$). In 60 nm tuning range, the output power variation was less than 1.5 ㏈ and SMSR was 35 ㏈.