Each critical quantity optical gain, differential refractive index change, linewidth enhancement factor that is used in the model requires long mathematical calculations with a strong background knowledge. Theoretical and experimental study of optical gain and. We have used an optical selfmixing technique to measure the linewidth enhancement factor of a terahertz quantum cascade laser. We report calculations of the linewidth enhancement factor for. Nov 15, 20 this paper presents a closedform analysis of the synchronized quantum cascade laser qcl and studies analytically the effect of linewidth enhancement factor lef on the frequency response of the qcl. A complete cad model for typei quantum cascade lasers with.
Laser linewidth is the spectral linewidth of a laser beam two of the most distinctive characteristics of laser emission are spatial coherence and spectral coherence. Spectral behavior of linewidth enhancement factor of a midinfrared quantum cascade laser. Apr 21, 2006 read measurement of the linewidth enhancement factor of quantum cascade lasers by the selfmixing technique, proceedings of spie on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Thermally insensitive determination of the linewidth. Osa importance of the microscopic effects on the linewidth. We find that contrary to previous predictions of a zero linewidth enhancement factor, it has a value of 0. Due to the tight confinement of charge carriers in quantum dots, they exhibit an electronic structure similar to atoms. We present measurements of the linewidth enhancement factor of a distributed feedback quantum cascade laser. Spectral purity and tunability of terahertz quantum cascade laser sources based on intracavity differencefrequency generation. Intrinsic linewidth of quantum cascade laser frequency combs francesco cappelli1,2, gustavo villares 1, sabine riedi, and j erome faist1, 1institute for quantum electronics, eth zurich, 8093 zuric h. Grantee research project results search research project. Experimental results using the amplified spontaneous emission spectroscopy of a typei quantum cascade laser are presented. A quantum dot laser is a semiconductor laser that uses quantum dots as the active laser medium in its light emitting region. Pereiraa materials and engineering research institute, sheffield hallam university, s1 1wb, sheffield, uk the linewidth enhancement.
Researchers provide experimental evidence of intrinsic linewidths approaching the quantum limit in a gaasalgaas quantum cascade laser emitting at. This represents the rst demonstration of a subradiative linewidth for any laser. Pdf by measuring the frequencynoise power spectral density of a cryogenicallycooled midinfrared quantum cascade laser, we investigate the different. The experiment is in agreement with the most recent theory on the fundamental. Electrically pumped photonic crystal distributed feedback quantum cascade lasers volume 1076 manijeh razeghi, yanbo bai, steven slivken, wei zhang. The method is applied to fabryperot, vcsel, external cavity laser ecl, dfb, quantum cascade laser. Linewidth enhancement factor of semiconductor lasers. Rp photonics encyclopedia linewidth enhancement factor. Linewidth enhancement factor of a typei quantum cascade laser m. Qc lasers have a symmetrical gain spectrum because the optical transition occurs between conduction subbands. Linewidth enhancement factor in gaasalgaas multiquantum. A nonzero lef at the gain peak is obtained due to these combined microscopic effects. The linewidth enhancement factor is investigated by analyzing optical feedback induced.
Comparison of linewidth enhancement factors in midinfrared. The possibility of developing ganbased qcls is also shown. Linewidth broadening factor and gain compression in. We clearly observed different values for the linewidth enhancement factor. Quantumlimited frequency fluctuations in a terahertz laser. Linewidth enhancement factor an overview sciencedirect topics. Dec 12, 2012 a broadband, compact, allelectrically driven midinfrared frequency comb based on a quantum cascade laser widens the scope of application of combs in this frequency range beyond that of sources. Due to their high performances, midinfrared quantum cascade lasers qcls have. Chuanga department of electrical and computer engineering, university of illinois at urbanachampaign.
We study a fivevariable electronhole model for a quantumdot qd laser subject to optical feedback. Osa linewidth enhancement factor in semiconductor lasers. Observing the intrinsic linewidth of a quantumcascade laser. Microscopic density matrix analysis on the linewidth enhancement factor lef of both midinfrared midir and terahertz thz quantum cascade lasers qcls is reported, taking into account of the many body coulomb interactions, coherence of resonanttunneling transport and nonparabolicity. Role of linewidth enhancement factor on the frequency. Midinfrared frequency comb based on a quantum cascade laser. More precisely, it is the width of the power spectral density of the emitted electric field in terms of frequency, wavenumber or wavelength. Using the hakkipaoli method, the optical gain spectra of the laser are e. Purcell enhancement strong coupling do we need a qw.
Linewidth enhancement factor of a typei quantumcascade laser. The linewidth enhancement fador in single quantum well grinsch semiconductor lasers is investigated theoretidy and experimentally. Linewidth enhancement factor of a typei quantumcascade. As expected, a much lower lef is found than is common for interband lasers, but instead of the predicted value of zero, the lef depends on the laser conditions and can be as high as 0. Results from roundrobin measurements in cost 288 asier villafranca, javier lasobras, ignacio garces photonics technology group university of zaragoza, pt walqa, ed. Gain compression and linewidth enhancement factor in mid. Jungho kim, maytee lerttamrab, shun lien chuang, fellow, ieee, claire gmachl. We present measurements of the linewidth enhancement factor of a distributed feedback quantum cascade laser dfbqcl using the socalled selfmixing technique. A comparative measurement is reported of the linewidth enhancement factor of bulk and multiple quantum well mqw longwavelength diode lasers using the chirp halfwidth product method. Grillot, measurements of the linewidth enhancement factor of midinfrared quantum cascade lasers by different optical feedback techniques aip advances 6, 01521210152127 2016.
From a twolevel limit to gain without inversion conditions m. Cthk1 linewidth enhancement factor of semiconductor lasers. Phase locking and spectral linewidth of a twomode terahertz. Extensive study of the linewidth enhancement factor of a. We obtained very low linewidth enhancement factor of 0. The abovethreshold linewidth enhancement factor of a midinfrared quantum cascade laser. Importance of the microscopic effects on the linewidth enhancement factor of quantum cascade lasers tao liu,1 kenneth e. We consider the case of a low linewidth enhancement factor and a short external cavity. Electrically pumped photonic crystal distributed feedback. Jul 15, 2012 researchers provide experimental evidence of intrinsic linewidths approaching the quantum limit in a gaasalgaas quantum cascade laser emitting at 2. This study presents a simple, single and an accurate computeraided design model for quantum cascade laser based on multilayer perceptrons. The flank of the r14 rovibrational absorption line of carbon monoxide at 2196. The amplitude of each modulation sideband, determined by j k m. Spectral gain profile of a multistack terahertz quantum cascade laser.
Using the hakkipaoli method, the optical gain spectra of the laser are extracted for the wavelength of 8. Introduction due to their high performances, midinfrared. Spectral purity and tunability of terahertz quantum. The lower linewidth enhancement factor 77 results in lower linewidth lasers, as well as lower chirp and lower reflection sensitivity 78. However, a narrow linewidth is generally not achieved in practice in freerunning qcls as a result of undesired noise that compromises their spectral. Unlike diode lasers, the lw enhancement factor of qcls can be either positive. We report on the measurement of the frequency noise properties of a 4. Linewidth enhancement factor an overview sciencedirect. The possibility of reducing the relative intensity noise rin of a quantum cascade laser is demonstrated. It provides direct evidence of the leveling of this noise down to a white noise plateau, corresponding to an intrinsic linewidth of a few hundred hz. For thin wells a small linewidth enhancement factor is obtained which clamps with increasing carrier density, in contrast to the monotonous increase observed for thicker wells. Linewidth enhancement factor of terahertz quantum cascade lasers. The linewidth enhancement factors for two typei quantum wells based on inassb are 2. Measurement of the linewidth enhancement factor of quantum.
A theoretical and experimental study of the optical gain and the linewidth enhancement factor lef of a typei quantumcascade qc laser is reported. Clamping of the linewidth enhancement factor in narrow. Roundrobin measurement within cost 288 action the cost 288 action nanoscale and ultrafast. Qcls have the potential to be a narrowlinewidth light source with an intrinsic linewidth of a few hundred hertz only that results from their closetozero henrys linewidth enhancement factor. In this study, a simple and a single complete cad model is obtained for type i quantum cascade laser based on characteristic quantities optical gain, refractive index change, linewidth enhancement factor. Rp photonics encyclopedia linewidth, bandwidth, laser. Introduction one property that distinguishes semiconductor lasers from most other laser systems is that there is a strong. Recent progress in quantum cascade lasers and applications 1537 regime, i. This study presents a simple, single and an accurate computeraided design model for quantumcascade laser based on multilayer perceptrons. As such, the measured voltage at laser contacts at steady state can be shown to be proportional. These findings are consistently explained by a detuned loading approach based on modifying the alpha parameter. Modulation dynamics of inpbased quantum dot lasers and. Gain compression and linewidth enhancement factor in midir quantum cascade lasers.
Measurements of the linewidth enhancement factor of mid. Quantum cascade laser, linewidth enhancement factor, optical. A complete cad model for typei quantum cascade lasers. An overview is prefaced, including a brief description of their beginnings and operating basics. Linewidth enhancement factor of a thz quantum cascade. The linewidth enhancement factor is investigated by analyzing optical feedback induced changes of the emission properties of the laser. Nanoscale displacement sensing based on nonlinear frequency. Sep 30, 2003 experimental results using the amplified spontaneous emission spectroscopy of a typei quantumcascade laser are presented. Frequencynoise dynamics of midinfrared quantum cascade lasers. Linewidth broadening factor and gain compression in quantum. Measurements of the linewidth enhancement factor of midinfrared. Measurement of linewidth enhancement factor of different. In this work, the linewidth enhancement factor of a midinfrared quantum cascade laser emitting around 5. Linewidth enhancement factor of terahertz quantum cascade.
The linewidth enhancement factor lef of terahertz quantum cascade lasers is measured using an optical feedback selfmixing technique. However, active region materials based on the typeii, inasgainsb system have linewidth. The abovethreshold linewidth enhancement factor of a midinfrared quantum cascade laser structure operated at 10. Unveiling spectral purity and tunability of terahertz quantum cascade laser. Cthk1 linewidth enhancement factor of semiconductor. Precise knowledge of the linewidth enhancement factor of a semiconductor laser under actual operating conditions is of prime importance since this parameter dictates various phenomena such as linewidth broadening or optical nonlinearities enhancement. Room temperature operation of 650 nm algaas multiquantumwell laser diode grown by molecular beam epitaxy tadashi saku, hidetoshi iwamura, yoshiro hirayama et al. Experimental results using the amplified spontaneous emission spectroscopy of a typei quantumcascade laser are presented.
Materials used, as well as growth methods, are also described. Gain compression and linewidth enhancement factor in midinfrared quantum cascade lasers. The model is based on artificial neural networks anns which is optimized by a new algorithm called artificial bee colony abc. Thz quantum cascade lasers resonant tunneling diodes could we try to improve on qcls learning from rtds. Frequency and phaselock control of a 3 thz quantum. The linewidth enhancement factor of intersubband lasers. Pdf linewidth enhancement factor of terahertz quantum. Ieee journal of selected topics in quantum electronics 2015. Apr 14, 2006 we present measurements of the linewidth enhancement factor of a distributed feedback quantum cascade laser dfbqcl using the socalled selfmixing technique. Theoretical and experimental study of optical gain and linewidth. While spatial coherence is related to the beam divergence of the laser, spectral coherence is evaluated by measuring the linewidth of laser radiation. A theoretical and experimental study of the optical gain and the linewidth enhancement factor lef of a typei quantum cascade qc laser is reported. Feb, 2016 in this work, the linewidth enhancement factor of a midinfrared quantum cascade laser emitting around 5. Therefore, by measuring the amplitude of each modulation sideband, the linewidth enhancement factor of the transmitter can be determined.
The linewidth enhancement factor of dilute nitride. Summarizing, the applications of these structures cover a broad range, including spectroscopy. As expected, a much lower lef is found than is common for. As expected, a much lower lef is found than is common for interband lasers, but instead of the predicted value of zero, the lef. Demonstration of a selfmixing displacement sensor based. Quantum cascade laser, linewidth enhancement factor, optical feedback, gain compression 1. Detuning characteristics of the linewidth enhancement. Cho, linewidth enhancement factor of a typei quantumcascade laser, j. Although mqw lasers provide substantially improved chirp performance compared with bulk devices, this depends considerably on the drive conditions when gain. Linewidth enhancement factor of a typeii quantumcascade. By phasedependent optical feedback from a short, piezocontrolled external cavity configuration, it is possible to achieve up to 9. The abovethreshold linewidth enhancement factor of a midinfrared quantum cascade laser structure operated at 10c is determined experimentally using two different methods based on optical feedback. Measurements of the linewidth enhancement factor of midinfrared quantum cascade lasers by different optical feedback techniques.
Narrow linewidth quantum cascade lasers as ultrasensitive. Measurement of the linewidth enhancement factor of. The factor 12 serves to convert the change of power gain. Introduction quantum cascade lasers have been proven to be sensitive to external perturbations such as external optical feedback and injection and to display nonlinear phenomena. From resonant tunneling diodes to quantum cascade lasers. The model includes microscopically computed coulomb scattering rates. Modulation dynamics of inpbased quantum dot lasers and quantum cascade lasers. Recent progress in quantum cascade lasers and applications. Recently, we have demonstrated that the intrinsic linewidth of quantum cascade lasers qcls can go beyond the radiative lifetime of the upper level. Measurement of linewidth enhancement factor of different semiconductor lasers in operating conditions guido giuliania, silvano donati a, wolfgang elsasser b a dipartimento di elettronica, universita di pavia, via ferrata 1, i27100 pavia, italy. Read measurement of the linewidth enhancement factor of quantum cascade lasers by the selfmixing technique, proceedings of spie on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Research project publication details compact multi. Quantum cascade lasers, midinfrared photonics, linewidth enhancement factor, alpha factor 1. Basic properties, linewidth enhancement factor and spectral linewidth of.
For pcdfb laser performance, the linewidth enhancement factor lef plays an important role in controlling the optical. We directly measured the optical gain, refractive index change, and the linewidth enhancement factor of a typeii quantum cascade laser. The system combines the inherent sensitivity of qcls to optical reinjection and their ultrastability in the strong feedback regime where nonlinear. Effects of resonant tunneling and dynamics of coherent. Linewidth enhancement factor of a typei quantumcascade laser m. Importance of the microscopic effects on the linewidth. Enhancement factor of fabry perot quantum cascade laser naoki kumazaki, yohei takagi, mikito ishihara et al.
This paper presents a closedform analysis of the synchronized quantum cascade laser qcl and studies analytically the effect of linewidth enhancement factor lef on the frequency response of the qcl. A broadband, compact, allelectrically driven midinfrared frequency comb based on a quantum cascade laser widens the scope of application of combs in. Intrinsic linewidth of quantum cascade laser frequency combs. Computeraided design model for a quantumcascade laser. Room temperature operation of 650 nm algaas multi quantum well laser diode grown by molecular beam epitaxy tadashi saku, hidetoshi iwamura, yoshiro hirayama et al. Pdf quantum cascade laser wavelength tuning due to. Modulation dynamics of inpbased quantum dot lasers and quantum cascade lasers cheng wang to cite this version.
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