• Title/Summary/Keyword: mode-locked laser

Search Result 128, Processing Time 0.022 seconds

Characteristics of Injection-Locked High Power Diode Laser (고출력 다이오드 레이저의 주입-잠금 과정 연구)

  • 문한섭;김중복;이호성;양성훈;김점술
    • Korean Journal of Optics and Photonics
    • /
    • v.6 no.3
    • /
    • pp.222-227
    • /
    • 1995
  • A single mode, 100-mW diode laser was injection-locked by the master laser which was spectrally narrowed with Littman-type grating feedback. In the incomplete-injection-locking, we observed that two frequencies were simultaneously generated from the slave laser. The power ratio and frequency shift of two frequency components were proportional to the square of injected laser intensity. When the ratio of the injection intensity to the slave laser intensity was about $10^{-3}$, the injection-locking bandwidth was to be about 1.4 GHz. The bandwidth proportionally increased to the square root of the injection intensity, which was in good agreement with the theoretical predictions. The Iinewidth of the locked-laser was about 2.5 MHz, which was five times as narrow as that of free-running operation. ation.

  • PDF

Dependence of Mode Locked Yb-doped Fiber Laser Output on the Size of the Beam Incident upon a Semiconductor Saturable Absorber Mirror (반도체 포화 흡수체 거울에 입사되는 광의 크기에 따른 모드 잠금된 Yb 첨가된 광섬유 레이저 출력 특성)

  • Moon, Dong Joon;Kim, Myung Jin;Ahan, Cheol Yong;Kim, Nam Seong;Kim, Hyun Su
    • Korean Journal of Optics and Photonics
    • /
    • v.23 no.3
    • /
    • pp.103-107
    • /
    • 2012
  • We investigate the dependence of the output of a mode locked Yb-doped fiber laser on incident intra-cavity intensity on a semiconductor saturable absorber mirror (SESAM). To vary the incident intra-cavity intensity, we change the beam spot size on a SESAM by varying the focal length of a lens installed in the front of the SESAM.

Spectral Comb Stabilization of a Mode-Locked Semiconductor Fiber Ring Laser by External Optical Injection (외부 광주입에 의한 모드 잠금된 고리형 광섬유 레이저의 스펙트럼 빗살 안정화)

  • Seo, Dong-Sun
    • Journal of IKEEE
    • /
    • v.15 no.4
    • /
    • pp.313-318
    • /
    • 2011
  • The effects of external continuous wave optical injection on spectral comb of a 10 GHz harmonically mode-locked semiconductor fiber ring laser have been studied. Greater than 40 dB spectral deeps in the spectral comb and greater than 30 dB reduction of supermode beating noise are achieved by injecting coherent light with ~ 100 KHz spectral width. To examine the possibility of using a low-cost seed source, we replace the seed source by a DFB laser with ~ 10 MHz spectral width. It shows similar spectral deeps, however supermode beating noise enhancement, rather than reduction, is observed.

Arbitrary Waveform Generation via Spectral Line-by-Line Pulse Shaping on Mode-Locked Pulses

  • Seo, Dong-Sun;Jiang, Zhi;Weiner, Andrew M.
    • Journal of IKEEE
    • /
    • v.10 no.2 s.19
    • /
    • pp.116-122
    • /
    • 2006
  • We have built a grating-based, high-resolution, spectral line-by-line pulse shaper. By controlling individual spectral lines of a mode-locked laser output, we demonstrate the interesting functionalities of the pulse shaper for arbitrary waveform generation, such as width tunable pulse generation, phase controlled waveform generation, microwave waveform generation, etc.

  • PDF

Modulation Depth Dependence of Timing Jitter and Amplitude Modulation in Mode-Locked Semiconductor Lasers (모드잠김 반도체 laser의 타이밍 지터및 크기 변조의 변조 신호 크기 의존성)

  • Kim, Ji-hoon;Bae, Seong-Ju;Lee, Yong-Tak
    • Proceedings of the Optical Society of Korea Conference
    • /
    • 2000.02a
    • /
    • pp.276.2-278
    • /
    • 2000
  • In a recent years, a number of approaches have been studied, including passive, active, and hybrid mode-locking of semi-conductor lasers for short pulse generation and research has been devoted to achieve low timing-jitter operation since the timing jitter is unfavorable for system applications. Among the methods of mode locking, passive mode locking does not need external rf drives, and therefore the operation and fabrication procedures are simplified. In spite of these attractive advantages of passive mode-locked laser, it has critical drawbacks such as large timing jitter and the difficulty in synchronization with external circuits. Their inherent large timing jitter value was shown to be suppressed to certain levels by means of hybrid mode-locking technique$^{(1)}$ , where the saturable absorber section was modulated by an external signal with the cavity round trip frequency. Furthermore, the subharmonic mode-locking (SHML) technique alleviates the restrictions of high speed driving electronics. It has been demonstrated experimentally$^{(1)}$ that the hybrid subharmonic mode-locking technique has lead to significant reduction of the timing jitter. (omitted)

  • PDF

Femtosecond Mid-IR Cr:ZnS Laser with Transmitting Graphene-ZnSe Saturable Absorber

  • Won Bae Cho;Ji Eun Bae;Seong Cheol Lee;Nosoung Myoung;Fabian Rotermund
    • Current Optics and Photonics
    • /
    • v.7 no.6
    • /
    • pp.738-744
    • /
    • 2023
  • Graphene-based saturable absorbers (SAs) are widely used as laser mode-lockers at various laser oscillators. In particular, transmission-type graphene-SAs with ultrabroad spectral coverage are typically manufactured on transparent substrates with low nonlinearity to minimize the effects on the oscillators. Here, we developed two types of transmitting graphene SAs based on CaF2 and ZnSe. Using the graphene-SA based on CaF2, a passively mode-locked mid-infrared Cr:ZnS laser delivers relatively long 540 fs pulses with a maximum output power of up to 760 mW. In the negative net cavity dispersion regime, the pulse width was not reduced further by inhomogeneous group delay dispersion (GDD) compensation. In the same laser cavity, we replaced only the graphene-SA based on CaF2 with the SA based on ZnSe. Due to the additional self-phase modulation effect induced by the ZnSe substrate with high nonlinearity, the stably mode-locked Cr:ZnS laser produced Fourier transform-limited ~130 fs near 2,340 nm. In the stable single-pulse operation regime, average output powers up to 635 mW at 234 MHz repetition rates were achieved. To our knowledge, this is the first attempt to achieve shorter pulse widths from a polycrystalline Cr:ZnS laser by utilizing the graphene deposited on the substrate with high nonlinearity.

Laser Doppler Vibrometer with Self Vibration Compensation (자체 진동 보상기능을 가진 레이저 도플러 진동측정계에 관한 연구)

  • Lee, Young-Jin;Kim, Ho-Seong
    • Proceedings of the KIEE Conference
    • /
    • 2001.11a
    • /
    • pp.53-55
    • /
    • 2001
  • A dual probe laser Doppler vibrometer (LDV) that has one laser source and provides two independent object beams has been developed for the first time. An electronic circuit that converts light signal to electronic signal has been also developed using phase locked loop(PLL). It was found that this types of dual probe LDV can be used in differential mode and self-vibration compensation mode.

  • PDF

Laser Doppler Vibrometer with self vibration compensation (자체 진동 보상기능을 가진 레이저 도플러 진동측정계에 관한 연구)

  • Lee, Young-Jin;Kim, Ho-Seong
    • Proceedings of the KIEE Conference
    • /
    • 2001.07c
    • /
    • pp.1838-1840
    • /
    • 2001
  • A dual probe laser Doppler vibrometer (LDV) that has one laser source and provides two independent object beams has been developed for the first time. An electronic circuit that converts light signal to electronic signal has been also developed using digital phase locked loop(DPLL). It was found that this types of dual probe LDV can be used in differential mode and self-vibration compensation mode.

  • PDF

Mode Locking of AlGaAs Semicondctor Laser Traveling Wave Amplifiers (AlGaAs 진행파 반도체 레이저 광증폭기의 모드록킹)

  • 이창희;강승구;정기웅;임시종;유태경
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.32A no.1
    • /
    • pp.119-128
    • /
    • 1995
  • We report hybrid and passive mode-locking results of tilted-stripe AlGaAs semiconductor laser traveling wave amplifiers with saturable absorbers. Dependence ofthe pulse width on the mode locking frequency, the bandwidth of spectral filters, and the bias current of the laser amplifier are investigated. We generate 4 ps optical pulses by using the hybrid mode locking technique. The repetition rate and the peak power of generated pulses are 516 MHz and 170 mW, respectively. The tuning range of uor mode locked laser is 10 nm with the center wavelength of 780 nm. We also generate 2.6 ps optical pulses with peak power of 830 mW by using the passive mode locking technique.

  • PDF

Stabilization and characterization of a 10 GHz harmonically mode-locked Er-doped fiber ring laser by suppression of relaxation oscillation (완화진동억압을 이용한 10 GHz 고조모드잠금된 고리형 어븀첨가 광섬유 레이저의 출력 안정화 및 특성 측정)

  • 장지웅;이유승;전영민;임동건
    • Korean Journal of Optics and Photonics
    • /
    • v.13 no.1
    • /
    • pp.58-64
    • /
    • 2002
  • Using Mach-Zehnder type intensity modulator, we stabilized a 10 GHz harmonically mode-locked dispersion-compensated fiber ring laser using a feedback controlling system, and we measured its stability. The laser was stabilized for more than 16 hours by controlling the cavity length to suppress the relaxation oscillation frequency component which had caused the laser output instability. The ms timing jitter and ms amplitude noise were measured to be 260-524 fsec and 4~11.5%, respectively, and BER test measurement showed a value of 10$^{-13}$ .