Impedance characteristics of quantum-well lasers

Weisser, S.; Esquivias, I.; Tasker, P.J.; Ralston, J.D.; Romero, B.; Rosenzweig, J.

doi:10.1109/68.392224

Cited by 63 publications

(34 citation statements)

References 11 publications

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“…The integrated spontaneous emission intensity is proportional to the density of carriers, and the emission spectra provides information on how the carriers are distributed in energy. If we assume the traditional carrier density squared dependence of the integrated spontaneous emission intensity, we can write the ratio of the barrier/SCH spontaneous emission to the well emission as (6) where is the total volume of the barrier and SCH regions, and and are the quadratic (radiative) recombination coefficients of the barrier/SCH and the well, respectively. The carrier densities in the barrier/SCH and well are and respectively.…”

Section: Rate Equations Analysismentioning

confidence: 99%

“…However, several difficulties have arisen when trying to measure the carrier lifetime in QW lasers. First, extracting the carrier lifetime from measurements is complicated by the additional high-frequency poles and zeros created by carrier transport across the separate confinement heterostructure (SCH) region, and capture and escape into and out of the QW [6], [7]. These problems can be minimized by proper laser design and by using small-signal measurement techniques that reduce the frequency at which data must be acquired in order to extract the lifetime [8].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Carrier lifetime and recombination in long-wavelength quantum-well lasers

Pikal

Menoni²,

Temkin³

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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Abstract-We present a novel analysis for correcting the measured differential carrier lifetime to account for carrier population in both the barrier and separate confinement heterostructure (SCH) regions of quantum-well (QW) lasers. This analysis uses information obtained from the measured spontaneous emission spectra to correct the measured lifetime and obtain the intrinsic well lifetime. Once the intrinsic well lifetime is obtained, the intrinsic well recombination coefficients can also be obtained. We show that the carrier population in the barrier/SCH layers can significantly affect the measured carrier lifetime and the extracted recombination coefficients. We also show that this analysis yields transparency carrier density and differential gain numbers which are very different from those obtained with the traditional analysis and much closer to what is predicted for highly strained QW lasers. These differences indicate the importance of accounting for barrier/SCH carriers on the measurement of basic QW laser material properties.

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Section: Rate Equations Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Carrier lifetime and recombination in long-wavelength quantum-well lasers

Pikal

Menoni²,

Temkin³

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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“…5,6 This model does not consider the carrier transport and capture dynamics discussed elsewhere 7,8 because it was assumed that the capture time is small and the escape time from the wells is very large compared to the carrier lifetime in the wells. In this simple model, d is the effective lifetime of the carriers confined in the quantum wells, without considering the carrier distribution in the barriers and separate confinement regions.…”

Section: ͑1͒mentioning

confidence: 99%

Differential carrier lifetime in oxide-confined vertical cavity lasers obtained from electrical impedance measurements

Giudice¹,

Kuksenkov²,

Temkin³

et al. 1999

Applied Physics Letters

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Differential carrier lifetime measurements were performed on index-guided oxide-confined vertical cavity surface emitting lasers operating at 980 nm. Lifetimes were extracted from laser impedance measurements at subthreshold currents, with device size as a parameter, using a simple small-signal model. The carrier lifetimes ranged from 21 ns at 9 A, to about 1 ns at a bias close to threshold. For a 6ϫ6 m 2 oxide aperture device the threshold carrier density was n th ϳ2ϫ10 18 cm Ϫ3 . The effect of carrier diffusion was also considered. An ambipolar diffusion coefficient of D ϳ11 cm 2 s Ϫ1 was obtained. © 1999 American Institute of Physics. ͓S0003-6951͑99͒00507-0͔Carrier lifetime measurements are an important tool in semiconductor laser characterization. 1,2 Recently, a new electrical technique for differential carrier lifetime measurements was developed. 2 It originally applied to edge emitting lasers with bulk active region. More recently, it has been applied to vertical cavity surface emitting lasers ͑VCSELs͒ 3 with quantum wells ͑QWs͒ in the active region. In this letter, experimental results on differential carrier lifetimes in indexguided oxide-confined VCSELs are reported. Lifetimes were obtained from laser impedance measurements at subthreshold currents and the equivalent circuit modeling. Threshold carrier densities and the corresponding recombination parameters were calculated as a function of device size. In addition, the effect of lateral carrier diffusion out of the active region was also considered.Devices studied in this work were oxide-confined InGaAs VCSELs lasing at 980 nm. The current aperture was obtained by partial oxidation of two quarter-wavelength GaAlAs layers. 4 Lasers with aperture sizes in the range of 6-12 m had room temperature threshold currents from 220 to 600 A. The laser impedance was measured from 1 MHz up to 3 GHz. Measurements were performed for bias currents between 9 A and threshold. Figure 1 presents the frequency dependence of the measured impedance of a device with a ϳ8ϫ8 m 2 active region, with a threshold current I th Ϸ240 A, at 40 A of drive current. The measured laser impedance was modeled using the small-signal subthreshold equivalent circuit shown in the inset of Fig. 1. The parameters included in this model were the following: an inductance L associated with a bond wire, a parallel combination of a resistance R m and capacitance C m associated with the top mirror interfaces, and a parallel combination of a resistance R d and a capacitance C a representing the active region. The impedance of the bottom mirror was neglected. The total impedance of the circuit can be written aswhere d ϭR d C a is the characteristic time equal to the differential carrier lifetime. 5,6 This model does not consider the carrier transport and capture dynamics discussed elsewhere 7,8 because it was assumed that the capture time is small and the escape time from the wells is very large compared to the carrier lifetime in the wells. In this simple model, d is the effective lifetime of the carri...

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“…On the other hand, this method is not very accurate at high currents, where the value of the differential resistance, R d becomes diminishingly small. This model in general is correct only as long as the transport effects including the capture-escape process [55,56,57,69] can be neglected. In the case of highly doped MQW lasers this model is not accurately correct and more complicated model is required [56,57].…”

Section: Determination Of the Differential Carrier Lifetime From The mentioning

confidence: 99%

“…The second equation describes the balance of photons inside the laser cavity. In this set of equations two important processes are ignored: carrier transport through the SCH and MQW layers [55] and carrier capture into quantum wells (in case of QW lasers) [56,57].…”

Section: Electrical and Optical Measurements Of Rf Modulation Responsmentioning

confidence: 99%

Advances in Measurements of Physical Parameters of Semiconductor Lasers

Shtengel¹,

Kazarinov²,

Belenky

et al. 1998

Int. J. Hi. Spe. Ele. Syst.

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We present a summary of advances in characterization techniques allowing for comprehensive study of physical processes in semiconductor lasers. 5. Electrical and optical measurements of RF modulation response below threshold. 5.1. Determination of the differential carrier lifetime from the device impedance. 5.2. Determination of the differential carrier lifetime from the optical response measurements. 6. Optical measurements of RF modulation response and RIN above threshold 6.1. Determination of the resonant frequency and damping factor using carrier subtraction technique. Determination of the differential gain and the gain compression coefficient. 6.2. Determination of the resonant frequency and differential gain from the RIN measurements. 7. Measurements of the linewidth enhancement factor. 7.1. Measurements of linewidth enhancement factorfrom ASE and TSE spectra. 8. Measurements of the carrier temperature and carrier heating in semiconductor lasers. 8.1. Determination of carrier heating from wavelength chirp and TSE measurements. 9. References.

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Impedance characteristics of quantum-well lasers

Cited by 63 publications

References 11 publications

Carrier lifetime and recombination in long-wavelength quantum-well lasers

Carrier lifetime and recombination in long-wavelength quantum-well lasers

Differential carrier lifetime in oxide-confined vertical cavity lasers obtained from electrical impedance measurements

Advances in Measurements of Physical Parameters of Semiconductor Lasers

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