• Title/Summary/Keyword: DFB(Distributed Feedback)

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The Research on the Heated CWDM(Coarse Wavelength Division Multiplexing) Optical Transceiver for the Wavelength Compensation at the Low Temperature (저온 파장 보상을 위한 히터 내장형 CWDM(Coarse Wavelength Division Multiplexing) 광 송수신기에 관한 연구)

  • Kwon, Yoon-Koo;Park, Kyoung-Su;Lee, Ji-Hyun;Kim, Chang-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.3
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    • pp.1263-1269
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    • 2012
  • This paper is the research on the heated CWDM optical transmitter for the wavelength compensation at the low temperature. In general, the wavelength deviation of DFB laser is around 0.1 nm/C. The wavelength of DFB laser shifts to longer(shorter) wavelength according to the temperature increase(decrease). Typical CWDM optical communication network has 20 nm channel spacing from reference center wavelength per each channel. There is some limitation problem in the range of operating temperature due to the channel interference. For solving the limited temperature range problem, especially at the low temperature, we use the heater on the DFB laser. As a result, we could realize the CWDM optical transmitter to meet +/-6.5 nm from reference center wavelength in the range of temperature at $-40{\sim}+85^{\circ}C$, which is applicable to the industrial field.

Ultrafast pulse train generation due to mode-beating in multi-section (다전극 DFB 레이저에서 모드비팅에 의한 초고속펄스열 생성)

  • Kim, Byoung-Sung;Chung, Young-Chul;Kim, Sun-Ho
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1859-1860
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    • 1997
  • 다전극 DFB(distributed feedback) 레이저서, 레이징모드간 비팅을 통하여 초고속으로 자려펄스열을 발생시킬 수 있음을 제안한다. 이러한 자려펄스생성을 수정된 시영역 동적 모델(large signal time-domain dynamic model)을 이용하여 조사하였다.

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반절연 InP를 이용한 초고속 DFB 레이저 다이오드의 제작 및 특성 연구

  • 주홍로;김형문;김정수;오대곤;박종대;김홍만;편광의
    • Proceedings of the Optical Society of Korea Conference
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    • 1995.06a
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    • pp.11-17
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    • 1995
  • 반절연 InP를 전류 차단층으로 사용하는 초고속 변조 Distributed Feedback (DFB) 레이저의 다이오드를 제작 하였다. Grating이 형성된 InP 기판에 유기금속 증착법 (MOVPE)을 사용하여 다중 양자 우물 구조 성장 시켜 메사구조를 연성 한후, 전류 차단층으로 반절연 InP를 성장 하였다. 제작된 레이저 다이오드는 평균 문턱전류 10 mA, 기울기효율 14%이며, 30mA 구동 전류에서 10GHz 이상의 3dB 대역폭 특성을 보였다.

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Equi-spaced multichannel stabilization with a reference frequency from ($^13C_2H_2$) molecules and optical fiber fabry-perot filter (아세칠렌가스($^13C_2H_2$)분자의 흡수선을 이용한 기준 광신호 및 광섬유 파브리-페로 필터에 의한 등간격 다중채널의 안정화)

  • 이현재;류갑열;이동호;박창수
    • Korean Journal of Optics and Photonics
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    • v.8 no.1
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    • pp.68-72
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    • 1997
  • Using one of the absorption lines of $^{13}C_2H_2$ molecules near the zero dispersion wavelength(1549.49nm) of dispersion shifted fiber, we stabilized center frequency of an optical fiber Fabry-Perot filter. The free spectral range of the filter is 100 GHz for 100 GHz channel allocation. For equi-spaced three channel multiplexing, channel locking of three DFB-LDs to transmission peaks of the fiber Fabry-Perot filter was tried. To investigate the effect of dithering current applied to each DFB-LD, the change of DFB-LD linewidth was measured.

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Modeling for DC characteristics of DFB-LD (DFB-LD의 DC와 AC 특성 분석)

  • 김호진;안상호;엄진섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.5
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    • pp.1372-1383
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    • 1998
  • In this paper, modeling for DC and AC characteristics analysis of DFB-LD was performed considering effects of .lambda./4-shifted gratingandspatial hole burning within a laser diode cavity. From the simulation for DC characteristics, Light-Current curve, optical power distribution and carrier density distribution within the cavity can be obtained. The simulation for AC characteristics porovides IM response and the amplitude and phase and the amplitude and phase response of FM with excellent accuracy.

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Fabrication of 1.55.mu.m RWG DFB lasers (1.55.mu.m RWG-DFB 레이저 제작에 관한 연구)

  • 김중연;강명구;전현성;오환술
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.469-472
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    • 1998
  • InGaAsP/InP ridge waveguide(RWG) distributed feedback(DFB) lasers (LD) operating at 1.55.mu.m were fabricated by a two step MOCVD process. The CW laser threshold and the slope efficiency from these lasers are 22.5mA and 0.127mW/MA perfacet at room temperature. Single longitudinal mode operation with side mode suppression of more than 30dB is obtained at 5mW. The temperature sensitivity and characteristic temperature (T$_{0}$) from DFB lasers were obtained 1.0.angs./.deg. C and 50.3K between 20.deg. C and 70.deg. C, respectively.y.

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In-line Dual-Mode DBR Laser Diode for Terahertz Wave Source

  • Chung, Youngchul
    • Current Optics and Photonics
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    • v.4 no.6
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    • pp.461-465
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    • 2020
  • A dual-mode laser terahertz source consisting of two in-line distributed Bragg reflector (DBR) laser diodes (LD) is proposed. It is less susceptible to residual reflections from facets than an in-line dual-mode distributed feedback (DFB) LD. The characteristics of the proposed terahertz source are theoretically investigated using a split-step time-domain simulation. It is shown that terahertz waves of frequencies from 385 GHz to 1725 GHz can be generated by appropriate thermal tuning of two DBR LDs. The dual-mode DBR LD terahertz source exhibits good spectral quality for residual facet reflectivity below 0.02, but facet reflectivity of the in-line dual-mode DFB LD terahertz source should be below 0.002 to provide similar spectral quality.

A Study on the Electric Circuit Model for the Direct FM Characteristics of DFB Semiconductor Lasers (DFB 반도체 레이저의 직접 주파수변조(DFM) 특성의 전기적 회로모델에 관한 연구)

  • 정순구;전광석;홍완희
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.12
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    • pp.2426-2438
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    • 1994
  • In this paper we present for the first time the electric circuit model for direct frequrncy modulation(FM) response of the conventional distributed-feedback(DFB) semiconductor laser diodes. Especially, in this paper, the proposed model includes not only the carrier density modulation effect, but also the temperature modulation effect determining the DFM characteristics of DFB characteristics of DFB semiconductor lasers. The DFM response due to injection current modulation was obtained as a function of modulation frequency from DC to a few GHz. The circuit model representing the temperature modulation effect is obtained from the structure of DFB LD chip and the simulation results are compared with the published experimental results. The circuit model representing the temperature modulation effect is obtained from the structure of DFB LD chip and the simulation results are compared with the published experimental results. The circuit model representing carrier density modulation effect is obtained from the rate equations of DFB lasers and the simulation results are compared with the results that were obtained by the conventional numerical analysis approach. The results showed good agreements.

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A Simple Analytic Method of Optical DFB Waveguides with Quarter-Wavelength Shifted Region (${\lambda}$/4 천이영역을 갖는 광 DFB도파로의 해석적 분석법)

  • Kim, June-Hwan;Ho, Kwang-Chun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.12
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    • pp.36-43
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    • 2001
  • We evaluate the optical characteristics of planar distributed feedback (DFB) waveguides with quarter-wavelength phase-shifter. To analyze explicitly its band-pass and resonance properties, we present and newly develop a modal transmission-line theory (MTLT) based on Floquet's theorem and Babinet's principle. The numerical results reveal that this approach offers a simple and analytic algorithm to analyze either the filtering or the oscillating characteristic of DFB gratings with quarter-wavelength phase-shifter, and has a novel physical insight that may not be achieved in other approximating approaches

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Analysis of the spontaneous emission spectrum of a multisection DFB structure device (다중 구역 DFB 구조 소자의 자연 방출 스펙트럼에 관한 해석)

  • 정기숙;김부균;이봉영
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.7
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    • pp.230-244
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    • 1996
  • We derive analytic expressions for the spontaneous emission spectrum (SES) of a multisection distributed feedback (DFB) structure device employing complex coupled gratings including the effects of both facets reflections. The multisection DFB structure device used in the analysis is a general model which allows the independent phase of a grating in each section, and the sections without gratings. The expressions are the same as those derived by makino and glinski in case the gratings are index coupled and the phase of a grating in each section, ${\varphi}_k$ is '0' which means the phase of gratings in the device is ocntinuous. The expressions for the SES of a phase-shift-controlled (PSC) DFB structure device using tunable devices are derived from the general expressions. The number of parametes of the expressions is reduced by using the parameter of effective phase shift defined by the sum of the phase shift in a PSC region and the difference of the phase of a grating in each active region. Equations showing the effect of both facets reflections and the effective phase shift on the SES are derived. The validaty of the equations is verified by computer simultions. Computer simulation results also show the possibility of evaluating the structure parametes of the device from its SES.

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