Measurement of spontaneous-emission factor of AlGaAs double-heterostructure semiconductor lasers

Suematsu, Y.; Akiba, S.; Hong, Tchang-Hee

doi:10.1109/jqe.1977.1069417

Cited by 80 publications

(15 citation statements)

References 6 publications

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“…In addition, we improved the fabrication process of GaInAsP-InP current injection devices and achieved the room temperature CW operation, for the first time, with a record-low threshold of 150 A. Also, we evaluated the spontaneous emission factor of this device by the curve fitting method [16].…”

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confidence: 99%

Ultrasmall and ultralow threshold GaInAsP-InP microdisk injection lasers: design, fabrication, lasing characteristics, and spontaneous emission factor

Fujita

Sakai

Baba

1999

IEEE J. Select. Topics Quantum Electron.

164

132

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Abstract-We have calculated lasing characteristics of current injection microdisk lasers of several microns in diameter, taking account of the scattering loss at center posts and the carrier diffusion effect. We found that the optimum width of the disk wing exposed to the air is 0.6-0.7 m and the minimum threshold current is nearly 10 A for the disk diameter of 2 m. The internal differential quantum efficiency can be 95% if the transparent carrier density is reduced to 7.5 2 10 17 cm 03 and the diffusion constant is increased to 8 cm 2 /s. In the experiment, we have obtained the room temperature continuous-wave operation of a GaInAsP-InP device of 3 m in diameter, for the first time, with a record low threshold of 150 A. This achievement was mainly owing to the reduction of the scattering loss at the disk edge, and hence the reduction of the threshold current density.The spontaneous emission factor was estimated to be 6 2 10 03 . This value was much reduced by the large detuning of the lasing wavelength against the spontaneous emission peak. A larger value over 0.1, which is expected for such a small device, will be obtained by the wavelength tuning and the narrowing of the spontaneous emission spectrum.

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confidence: 99%

Ultrasmall and ultralow threshold GaInAsP-InP microdisk injection lasers: design, fabrication, lasing characteristics, and spontaneous emission factor

Fujita

Sakai

Baba

1999

IEEE J. Select. Topics Quantum Electron.

164

132

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“…12 When applied to VCSELs, this technique is likely to be inaccurate. In very small devices, the temperature of the active region, and therefore the threshold and efficiency, are dependent on the drive current as a result of self-heating, and these effects require careful compensation.…”

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confidence: 99%

Spontaneous emission factor in oxide confined vertical-cavity lasers

Kuksenkov

Temkin

Lear

et al. 1997

Applied Physics Letters

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We report on measurements of the spontaneous emission factor for oxide-confined InGaAs vertical cavity surface emitting lasers. The spontaneous emission factor is determined as a function of the active layer volume from the measurement of small-signal harmonic distortion at threshold. For a 3ϫ3 m oxide aperture device we obtain spontaneous emission factor of 4.2•10 Ϫ2 at room temperature. © 1997 American Institute of Physics. ͓S0003-6951͑97͒03501-8͔The possibility of controlling spontaneous emission in semiconductor microcavities has attracted considerable attention due to predictions of essentially thresholdless lasing and enhanced modulation bandwidth. 1 The spontaneous emission factor ␤ has been measured for buried mesa VCSELs with dielectric mirrors, 2 gain-guided VCSELs, 3,4 optically pumped lasers with planar resonators, 5 and for air-post mesa VCSELs at low temperatures. 6 The ␤ factor of oxideconfined VCSELs was estimated from the spectral and angular width of the spontaneous emission. 7 The results reported thus far differ significantly from structure to structure and the measurement conditions, with the highest values of ␤ ϳ10 Ϫ2 observed at low temperatures. 5,6 The enhancement in the value of ␤ is expected to significantly affect the laser performance when the lateral dimensions of the cavity are reduced to less than 1 m. 8,9 Unfortunately, VCSEL size scaling is limited by increasing optical loss and consequently the threshold carrier density. In addition, the enhancement of spontaneous emission in a microcavity formed by distributed Bragg reflectors is limited by the finite width of the reflection band and the optical field penetration into the mirrors. 10 Oxide confined VCSELs are characterized by significantly reduced internal loss and have already demonstrated record performance levels in terms of the threshold current and power conversion efficiency. 11 Lasers with the lateral cavity dimensions below ϳ1 m appear feasible.Devices used in our measurements are based on three InGaAs quantum wells in the active region, and are designed to emit at 980 nm. Two quarter-wavelength Ga 0.02 Al 0.98 As layers, one above and one below the active region, are partially oxidized to form the current aperture. Devices with the aperture sizes in the range of 3-25 m exhibit threshold currents from 0.27 to 3.3 mA, and threshold voltages of 2.6-1.4 V.The conventional method of estimating the ␤ factor is based on the rate equations fitting the measured light-current ͑L-I͒ curve. 12 When applied to VCSELs, this technique is likely to be inaccurate. In very small devices, the temperature of the active region, and therefore the threshold and efficiency, are dependent on the drive current as a result of self-heating, and these effects require careful compensation. Larger index guided devices lase in multiple transverse modes ͓see Fig. 1͑b͔͒, and the modal distribution is also dependent on the drive current, even though calculations usually assume it to be constant.An alternative technique is used here to determine ␤. It i...

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“…In this case, the eigenvalue equation (6) and the recursion relation (9) can be used for TM modes, except that K and K i in (10) should be replaced by K /n and K i/nY.…”

Section: The Behaviors Of Laterally Propagating Modesmentioning

confidence: 99%

“…Verical-cavity surfaceemitting lasers (VCSELs) are good candidates for the investigation and realization of microcavity laser characteristics. The spontaneous emission factor of VCSELs has been measured based on the rate equation fitting the measured light-current curve [6][7][8][9], small-signal harmonic distortion at threshold [10][11][12], and other techniques [1 3-15]. Theoretical and experimental results show that y is inversely proportional to the laser cavity volume, and reducing the cavity volume is the main method to increase y.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of spontaneous emission factor in selectively oxidized vertical-cavity lasers with double oxide layers

Huang

1998

SPIE Proceedings

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The behaviors of lateral propagating modes in the aperture and the oxidized regions are investigated numerically for selectively oxidized vertical-cavity surface-emitting lasers (VCSELs). The results show that the lateral propagating modes in the oxidized region are greatly affected by the oxide layer due to its low index, the modes are divergence for the VCSELs with sufficient thick double oxide layers. So the coupling between the modes in the aperture and oxidized regions is very weak, and we can expect that the lateral spontaneous emission is greatly affected in this case. Ignoring the contribution of the lateral spontaneous emission, we calculate spontaneous emission factor by counting the total number of the guided modes in selectively oxidized VCSELs with double oxide layers. The results agree very well with the reported measurements and are inversely proportional to the lateral index step.

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Measurement of spontaneous-emission factor of AlGaAs double-heterostructure semiconductor lasers

Cited by 80 publications

References 6 publications

Ultrasmall and ultralow threshold GaInAsP-InP microdisk injection lasers: design, fabrication, lasing characteristics, and spontaneous emission factor

Ultrasmall and ultralow threshold GaInAsP-InP microdisk injection lasers: design, fabrication, lasing characteristics, and spontaneous emission factor

Spontaneous emission factor in oxide confined vertical-cavity lasers

Enhancement of spontaneous emission factor in selectively oxidized vertical-cavity lasers with double oxide layers

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