| 1. |
- Baveja, P. P., et al.
(author)
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Assessment of VCSEL thermal rollover mechanisms from measurements and empirical modeling
- 2011
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In: Optics Express. - 1094-4087 .- 1094-4087. ; 19:16, s. 15490-15505
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Journal article (peer-reviewed)abstract
- We use an empirical model together with experimental measurements for studying mechanisms contributing to thermal rollover in vertical-cavity surface-emitting lasers (VCSELs). The model is based on extraction of the temperature dependence of threshold current, internal quantum efficiency, internal optical loss, series resistance and thermal impedance from measurements of output power, voltage and lasing wavelength as a function of bias current over an ambient temperature range of 15-100 degrees C. We apply the model to an oxide-confined, 850-nm VCSEL, fabricated with a 9-mu m inner-aperture diameter and optimized for highspeed operation, and show for this specific device that power dissipation due to linear power dissipation (sum total of optical absorption, carrier thermalization, carrier leakage and spontaneous carrier recombination) exceeds power dissipation across the series resistance (quadratic power dissipation) at any ambient temperature and bias current. We further show that the dominant contributors to self-heating for this particular VCSEL are quadratic power dissipation, internal optical loss, and carrier leakage. A rapid reduction of the internal quantum efficiency at high bias currents (resulting in high temperatures) is identified as being the major cause of thermal rollover. Our method is applicable to any VCSEL and is useful for identifying the mechanisms limiting the thermal performance of the device and to formulate design strategies to ameliorate them.
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| 2. |
- Baveja, P. P., et al.
(author)
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Impact of photon lifetime on thermal rollover in 850-nm high-speed VCSELs
- 2012
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819489197 ; 8276
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Conference paper (peer-reviewed)abstract
- We present an empirical thermal model for VCSELs based on extraction of temperature dependence of macroscopic VCSEL parameters from CW measurements. We apply our model to two, oxide-confined, 850-nm VCSELs, fabricated with a 9-mu m inner-aperture diameter and optimized for high-speed operation. We demonstrate that for both these devices, the power dissipation due to linear heat sources dominates the total self-heating. We further show that reducing photon lifetime down to 2 ps drastically reduces absorption heating and improves device static performance by delaying the onset of thermal rollover. The new thermal model can identify the mechanisms limiting the thermal performance and help in formulating the design strategies to ameliorate them.
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| 3. |
- Westbergh, Petter, 1981, et al.
(author)
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40 Gbit/s error-free operation of oxide-confined 850 nm VCSEL
- 2010
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In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 46:14, s. 1014-1015
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Journal article (peer-reviewed)abstract
- Error-free transmission is demonstrated at bit rates up to 40 Gbit/s in a back-to-back configuration and up to 35 Gbit/s over 100 m multimode fibre using a directly modulated oxide confined 850 nm vertical cavity surface emitting laser.
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| 4. |
- Westbergh, Petter, 1981, et al.
(author)
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850 nm VCSEL Operating Error-Free at 40 Gbit/s
- 2010
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In: Semiconductor Laser Conference (ISLC), 2010 22nd IEEE International. - 0899-9406. - 9781424456833 ; , s. 154 - 155
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Conference paper (peer-reviewed)abstract
- We report on speed enhancement of 850 nm oxide confined VCSELs by photon lifetime reduction and demonstrate a 23 GHz modulation bandwidth and error-free operation at 40 Gbit/s.
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