• Title/Summary/Keyword: multi-section DFB lasers

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Analysis of Self-Pulsation Characteristics in Multi-Section Complex-Coupled DFB Lasers With Amplifying Optical Feedback (증폭된 광 귀환을 가자는 다중 전극 복소 결합 DFB 레이저에서 발생되는 self-pulsation 특성 해석)

  • Kim, Sang-Taek;Kim, Tae-Young;Kim, Boo-Gyoun;Leem, Young-Ahn;Park, Kyung-Hyun
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.527-534
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    • 2005
  • We investigate the pulsation characteristics in a multi-section DFB laser which is composed of one DFB section, phase tuning section, and gain section. Multi-section DFB lasers with anti-phase (AP) complex-coupled (CC) DFB structure show wide current ranges of gain and phase tuning sections fer stable pulsations compared to those with in-phase CC DFB structure or index-coupled DFB structure. For multi-section DFB lasers with AP CC DFB structure, the current range of a gain section for stable pulsations increases and the tuning range of the pulsation frequency increases as a coupling strength or a gain coupling coefficient increases Also, the tuning range using the phase variation in a phase tuning section increases. For a fixed coupling strength, the current ranges of gain and phase tuning sections for stable pulsations increase and the tuning range of the pulsation frequency increases as the length of a DFB section increases.

A Multi-Section Complex-Coupled DFB Laser with a Very Wide Range of Self-Pulsation Frequency and High Modulation Index (매우 넓은 영역의 Self-Pulsation 주파수와 높은 변조 지수를 가자는 다중 영역 복소 결합 DFB 레이저)

  • Kim, Boo-Gyoun;Kim, Tae-Young;Kim, Sang-Taek;Kim, Sun-Ho;Park, Kyung-Hyun
    • Korean Journal of Optics and Photonics
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    • v.17 no.2
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    • pp.191-197
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    • 2006
  • We analyze the self-pulsation(SP) characteristics due to mode beating of two modes emitted in a multi-section complex-coupled (CC) DFB laser composed of two DFB sections and a phase control section between them. SP frequency due to mode beating of the two modes is determined by the difference of grating periods in the two CC DFB regions. As the difference of grating periods in the two CC DFB regions increases, the SP frequency increases from very low frequency to the THz region. In the case of a mode which is not located in the stop band of the other DFB region, the mode propagates into the other DFB region without a high reflection, so that output powers emitted in a multi-section CC DFB laser have high modulation indexes due to the large interaction between the two modes.

Impact of facet reflectivity on self-pulsations in multi-section DFB lasers (다중 전극 DFB 레이저에서 단면 반사율이 self-pulsation에 미치는 영향)

  • 김상택;지성근;김부균
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.154-155
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    • 2002
  • 완전 광 3R(Retiming, Reshaping, Reamplification) 재생기는 WDM 시스템과 광 네트워크의 크기를 확장시키기 위하여 필요한 매우 중요한 소자이다. 완전 광 3R 재생기의 구현에서 입력 광 신호로부터 광 클락 추출은 가장 핵심적인 요소이다. 이러한 광 클락 추출을 위하여 모드락 레이저 다이오드와 다중 전극 DFB 레이저에서 self-pulsating 현상을 이용하는 방법이 많이 연구되고 있다. 독일의 HHI는 다중 전극 DFB 레이저에서 self-pulsating 현상을 이용하여 80 GHz 초고속 광 클락 추출과 25-82 GHz 전기적 튜닝 특성을 보였다. (중략)

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Effect of varying the coupling strength and section length on the self-pulsation characteristics of multisection index-coupled DFB lasers (다중 전극 Index-Coupled DFB 레이저에서 결합 세기 및 각 영역의 길이가 Self-Pulsation 동작 특성에 미치는 영향)

  • Kim, Sang-Taek;Kim, Tae-Young;Ji, Sung-Keun;Kim, Boo-Gyoun
    • Korean Journal of Optics and Photonics
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    • v.16 no.1
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    • pp.85-98
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    • 2005
  • As the number of compound cavity modes within the stopband of DFB sections decreases, the frequency of mode hopping decreases for the variation of $\Delta$λ$_{B}$, which represents the difference between the Bragg wavelengths of two DFB sections, so that the number of abrupt changes of pulsation frequencies decreases. In addition, the pulsation frequency varies continuously for the variation of the phase in a phase tuning section for a fixed $\Delta$λ$_{B}$. The number of compound cavity modes within the stopband decreases as the length of DFB sections increases and the length of a phase tuning section decreases. Thus stable self-pulsation operations for the variation of $\Delta$λ$_{B}$ and the phase in a phase tuning section could be obtained by proper selection of the coupling strength and the length of each section.ction.

A study on characteristics of self-pulsation due to the dispersive self-Q-switching in multi-section DFB lasers (다중 전극 DFB 레이저에서 dispersive Self-Q-Switching에 의해서 발생되는 self-pulsation 특성에 관한 연구)

  • 지성근;김상택;김부균
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.160-161
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    • 2003
  • 완전 광 3R(Retiming, Reshaping, Reamplification) 재생기는 WDM 시스템과 광 네트워크의 크기를 쉽게 확장시키기 위하여 필요한 매우 중요한 소자이다. 완전 광 3R 재생기의 구현에서 입력 광 신호로부터 광 클락을 추출하는 기술은 매우 중요한 기술이다. 이러한 광 클락 추출기술을 구현하기 위하여 모드락 레이저 다이오드와 다중 전극 OFB 레이저에서 self-pulsation 현상을 이용하는 방법이 많이 연구되고 있다. 모드락 레이저 다이오드를 이용한 방법은 모드 락킹 주파수가 레이저의 공진기의 길이에 의해서 결정되기 때문에 공진기의 길이를 정확하게 조절해야 한다는 단점을 가지고 있는 반면에 다중 전극 DFB 레이저의 경우 self-pulsation 주파수를 전기적으로 튜닝할 수 있다는 장점을 가지고 있다. (중략)

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