| 1. |
- Westbergh, Petter, 1981, et al.
(author)
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Single mode 1.3 ÎŒm InGaAs VCSELs for access network applications
- 2008
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In: Semiconductor Lasers and Laser Dynamics III. - : SPIE. ; 6997, s. 69970Y-1-8-
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Conference paper (peer-reviewed)abstract
- GaAs-based VCSELs emitting near 1.3 Όm are realized using highly strained InGaAs quantum wells and a large detuning of the cavity resonance with respect to the gain peak. The VCSELs have an oxide aperture for current and optical confinement and an inverted surface relief for suppression of higher-order transverse modes. The inverted surface relief structure also has the advantage of suppressing oxide modes that otherwise appear in VCSELs with a large detuning between the cavity resonance and the gain peak. Under large signal, digital modulation, clear and open eyes and error free transmission over 9 km of single mode fiber have been demonstrated at the OC-48 and 10 GbE bit rates up to 85°C. Here we review these results and present results from a complementary study of the RF modulation characteristics, including second order harmonic and third order intermodulation distortion, relative intensity noise (RIN), and spurious free dynamic range (SFDR). RIN levels comparable to those of single mode VCSELs emitting at 850 nm are demonstrated, with values from -140 to -150 dB/Hz. SFDR values of 100 and 95 dB·Hz2/3 were obtained at 2 and 5 GHz, respectively, which is in the range of those required in radio-over-fiber systems.
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| 2. |
- Bamiedakis, Nikos, et al.
(author)
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25 Gb/s data transmission over a 1.4 m long multimode polymer spiral waveguide
- 2014
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In: Conference on Lasers and Electro-Optics Europe - Technical Digest. - Washington, D.C. : OSA. - 9781557529992
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Conference paper (peer-reviewed)abstract
- Data transmission studies of a 1.4m long multimode polymer spiral waveguide using an 850nm VCSEL are presented. Error-free 25 Gb/s data transmission is demonstrated over that waveguide length, achieving a record bandwidth-length product of 21GHz×m.
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| 3. |
- Bamiedakis, N., et al.
(author)
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40 Gb/s data transmission over a 1 m long multimode polymer spiral waveguide
- 2014
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In: European Conference on Optical Communication, ECOC 2014; Cannes; France; 21 September 2014 through 25 September 2014. - 9782954944401 ; , s. Paper P.4.7-
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Conference paper (peer-reviewed)abstract
- We report record error-free data transmission of 40Gb/s over a 1m-long multimode polymer spiral waveguide. The waveguide imposes no significant transmission impairments in the link despite its highly-multimoded nature and long length, demonstrating its potential in high-speed board-level optical interconnections.
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| 4. |
- Bamiedakis, N., et al.
(author)
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40 Gb/s Data Transmission Over a 1-m-Long Multimode Polymer Spiral Waveguide for Board-Level Optical Interconnects
- 2015
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In: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 33:4, s. 882-888
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Journal article (peer-reviewed)abstract
- Optical interconnects have attracted considerable attention for use in short-reach communication links within high-performance electronic systems, such as data centers, supercomputers, and data storage systems. Multimode polymer waveguides, in particular, constitute an attractive technology for use in board-level interconnects as they can be cost-effectively integrated onto standard PCBs and allow system assembly with relaxed alignment tolerances. However, their highly multimoded nature raises important concerns about their bandwidth limitations and their potential to support very high on-board data rates. In this paper, we report record error-free (BER
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| 5. |
- Bamiedakis, N., et al.
(author)
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56 Gb/s PAM-4 data transmission over a 1 m long multimode polymer interconnect
- 2015
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In: CLEO: Science and Innovations, CLEO-SI 2015, San Jose; United States; 10-15 May 2015. - 9781557529688 ; , s. 2267-
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Conference paper (peer-reviewed)abstract
- Advanced modulation formats can enable >40 Gb/s data rates in waveguide-based optical interconnects without the need for high-specification optoelectronic components. Record 56Gb/s PAM-4 data transmission is demonstrated over a 1 m-long multimode polymer waveguide.
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| 6. |
- Baveja, Prashant, 1985, et al.
(author)
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Impact of device parameters on thermal performance of high speed oxide confined 850 nm VCSELs
- 2012
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In: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 48:1, s. 17-26
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Journal article (peer-reviewed)abstract
- We study the impact of device parameters, such asinner-aperture diameter and cavity photon lifetime, on thermal rollover mechanisms in 850-nm, oxide-confined, vertical-cavity surface-emitting lasers (VCSELs) designed for high-speed operation. We perform measurements on four different VCSELs of different designs and use our empirical thermal model for calculating the power dissipated with increasing bias currents through various physical processes such as absorption within the cavity, carrier thermalization, carrier leakage, spontaneous carrier recombination, and Joule heating. When reducing the topmirror reflectivity to reduce internal optical absorption loss we find an increase of power dissipation due to carrier leakage. There is therefore a trade-ff between the powers dissipated owing to optical absorption and carrier leakage in the sense that overcompensating for optical absorption enhances carrier leakage (and vice versa). We further find that carrier leakage places the ultimate limit on the thermal performance for this entire class ofdevices. Our analysis yields useful design optimization strategies for mitigating the impact of carrier leakage and should thereby prove useful for the performance enhancement of 850-nm, highspeed, oxide-confined VCSELs.
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| 7. |
- 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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| 8. |
- 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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| 9. |
- Castro, Jose Manuel, et al.
(author)
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48.7 Gb/s 4-PAM Transmission over 200 m of High Bandwidth MMF using an 850 nm VCSEL
- 2015
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In: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 27:17, s. 1799-1801
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Journal article (peer-reviewed)abstract
- We demonstrate 4-PAM 48.67 Gb/s transmission, using a directly modulated VCSEL, over 50, 100 and 200 m of multimode fiber with partial dispersion compensation properties. The results of our experiments indicate that 200 m reach is achievable with forward error correcting codes with small overhead.
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| 10. |
- Castro, Jose Manuel, et al.
(author)
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50 Gb/s 4-PAM over 200 m of High Bandwidth MMF using a 850 nm VCSEL
- 2015
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In: Optical Fiber Communication Conference 2015, Los Angeles, California, United States, 22–26 March 2015. - 9781557529374
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Conference paper (peer-reviewed)abstract
- Experiments for transmission of 50Gb/s, 4-PAM using direct modulated VCSEL over 100m and 200m of MMF with partial dispersion compensation properties are presented.
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