Semiconductor Lasers and Theory

Ohtsubo, Junji

doi:10.1007/978-3-642-30147-6_3

Cited by 21 publications

(6 citation statements)

References 47 publications

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“…The other potential source of high-frequency content relates to the oscillations in raw laser intensity. This appears as a ringing at the beginning of a scan due to the overshoot in laser output power when the injection current undergoes a large step-change, on the order of nanoseconds [38,39], induced by the square waveform (which can be related to the Gibbs phenomenon). Ringing can be observed at the beginning of the various square-wave pulses shown in figures 2 and 3.…”

Section: Detection Bandwidth Limitationsmentioning

confidence: 99%

Extended tuning of distributed-feedback lasers in a bias-tee circuit via waveform optimization for MHz-rate absorption spectroscopy

Nair

Minesi

Jelloian

et al. 2022

Meas. Sci. Technol.

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Variations in injection-current waveform are examined using diplexed RF-modulation with continuous-wave distributed-feedback (CW-DFB) lasers, with the aim to maximize the spectral tuning range and signal-to-noise ratio for MHz-rate laser absorption spectroscopy. Utilizing a bias-tee circuit, laser chirp rates are shown to increase by modulating the AC input voltage using square waves instead of sine waves and by scanning the laser below the lasing threshold during the modulation period. The effect of waveform duty cycle and leading-edge ramp rate are further examined. A spectral scan depth on the order of 1 cm-1 at a scan frequency of 1 MHz is achieved with a representative CW-DFB quantum cascade laser near 5 µm. Distortion of high-frequency optical signals due to detector bandwidth is also examined, and limitations are noted for applications with narrow spectral features and low-bandwidth detectors. Based on common detection system limitations, an optimization approach is established for a given detection bandwidth and target spectra. A representative optimization is presented for measurements of sub-atmospheric carbon monoxide spectra with a 200-MHz detection system. The methods are then demonstrated to resolve transient gas properties (pressure and temperature) via laser absorption spectroscopy at MHz rates in a detonation tube and shock tube facility. An appendix detailing a first-order model of high-speed distributed feedback laser tuning dynamics is also included to support the experimental observations of this work.

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Section: Detection Bandwidth Limitationsmentioning

confidence: 99%

Extended tuning of distributed-feedback lasers in a bias-tee circuit via waveform optimization for MHz-rate absorption spectroscopy

Nair

Minesi

Jelloian

et al. 2022

Meas. Sci. Technol.

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“…In both noise situations of this work, this reduction of the peak amplitude with the gain compression also comes with a relatively small frequency shift of the peak value. For instance for the FN, the shift ranges from about 2.7 × 10 5 Hz 2 /Hz at f = 2.2 GHz to 1.2 × 10 5 Hz 2 /Hz at f = 1.8 GHz; whereas for the RIN, it moves from about The FN is linked to the spectral linewidth through the relationship ∆ν = 2πFN| f≪fR [8,30]. With the increase of injection current, the FN shows an expected and typical decreasing behavior in the simulation (figure 9(a)), confirming the model.…”

Section: Noisementioning

confidence: 99%

Modeling of a quantum dot gain chip in an external cavity laser configuration

Ehlert¹,

Mugnier²,

He³

et al. 2021

Laser Phys.

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External cavity semiconductor lasers with strong optical feedback already exist using a gain chip medium. Owing to their ultrafast carrier dynamics, strong output power, and high temperature reliability, quantum dots as a gain medium are now envisioned as a promising solution to replace the current quantum well technology. This paper presents a semi-analytical rate equation model which is used to describe a quantum dot gain chip capable of lasing only with a free space external cavity laser. It investigates the evolution of the dynamical properties such as the turn-on delay and the damping rate. It also confirms the model's validity through the relative intensity noise and the frequency noise with respect to both material and device parameters like the linewidth enhancement factor, the gain compression factor, or the cavity length. Overall, this numerical investigation provides initial building blocks for future fabrication research and development of high performance devices including filters or gratings as wavelength-selective components.

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“…Here we do not derive the laser equations since they can be found in many textbooks and articles (see for example [19,20]). The analysis of a unidirectional travelling-wave ring resonator shows that the fundamental Maxwell-Bloch laser equations can be written in the form [6] …”

Section: Laser Equationsmentioning

confidence: 99%

“…As a result, laser diodes belong to class B and they are intrinsically stable. Laser diodes are, however, very sensitive to optical perturbations since their emission frequency is detuned from the peak of the gain spectrum producing an anomalous dispersion effect [6]. This explains why laser diodes can be easily brought into chaos by the introduction of external perturbations in the form of external optical feedback, optical injection or laser current modulation (see the review article [7]).…”

Section: Introductionmentioning

confidence: 99%

Chaotic He-Ne laser

Kuusela¹

2017

Eur. J. Phys.

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A He-Ne laser is an example of a class A laser, which can be described by a single nonlinear differential equation of the complex electric field. This laser system has only one degree of freedom and is thus inherently stable. A He-Ne laser can be driven to the chaotic condition when a large fraction of the output beam is injected back to the laser. In practice, this can be done simply by adding an external mirror. In this situation, the laser system has infinite degrees of freedom and therefore it can have a chaotic attractor. We show the fundamental laser equations and perform elementary stability analysis. In experiments, the laser intensity variations are measured by a simple photodiode circuit. The laser output intensity time series is studied using nonlinear analysis tools which can be found freely on the internet. The results show that the laser system with feedback has an attractor of a reasonably high dimension and that the maximal Lyapunov exponent is positive, which is clear evidence of chaotic behaviour. The experimental setup and analysis steps are so simple that the studies can even be implemented in the undergraduate physics laboratory.

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Semiconductor Lasers and Theory

Cited by 21 publications

References 47 publications

Extended tuning of distributed-feedback lasers in a bias-tee circuit via waveform optimization for MHz-rate absorption spectroscopy

Extended tuning of distributed-feedback lasers in a bias-tee circuit via waveform optimization for MHz-rate absorption spectroscopy

Modeling of a quantum dot gain chip in an external cavity laser configuration

Chaotic He-Ne laser

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