| 1. |
- Gustavsson, Johan, 1974, et al.
(författare)
-
High-speed 850-nm VCSELs for 40 Gb/s transmission
- 2010
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We have explored the possibility to extend the data transmission rate for standard 850-nm GaAs-based VCSELs beyond the 10 Gbit/s limit of today's commercially available directly-modulated devices. By sophisticated tailoring of the design for high-speed performance we demonstrate that 10 Gb/s is far from the upper limit. For example, the thermal conductivity of the bottom mirror is improved by the use of binary compounds, and the electrical parasitics are kept at a minimum by incorporating a large diameter double layered oxide aperture in the design. We also show that the intrinsic high speed performance is significantly improved by replacing the traditional GaAs QWs with strained InGaAs QWs in the active region. The best overall performance is achieved for a device with a 9 μm diameter oxide aperture, having in a threshold current of 0.6 mA, a maximum output power of 9 mW, a thermal resistance of 1.9 °C/mW, and a differential resistance of 80 Ω. The measured 3dB bandwidth exceeds 20 GHz, and we experimentally demonstrate that the device is capable of error-free transmission (BER
|
|
| 2. |
- Healy, S. B., et al.
(författare)
-
Active Region Design for High-Speed 850-nm VCSELs
- 2010
-
Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 46:4, s. 506-512
-
Tidskriftsartikel (refereegranskat)abstract
- Higher speed short-wavelength (850 nm) VCSELs are required for future high-capacity, short-reach data communication links. The modulation bandwidth of such devices is intrinsically limited by the differential gain of the quantum wells (QWs) used in the active region. We present gain calculations using an 8-band k.p Hamiltonian which show that the incorporation of 10% In in an InGaAs/AlGaAs QW structure can approximately double the differential gain compared to a GaAs/AlGaAs QW structure, with little additional improvement achieved by further increasing the In composition in the QW. This improvement is confirmed by extracting the differential gain value from measurements of the modulation response of VCSELs with optimized InGaAs/AlGaAs QW and conventional GaAs/AlGaAs QW active regions. Excellent agreement is obtained between the theoretically and experimentally determined values of the differential gain, confirming the benefits of strained InGaAs QW structures for high-speed 850-nm VCSEL applications.
|
|
| 3. |
- Westbergh, Petter, 1981, et al.
(författare)
-
40 Gbit/s error-free operation of oxide-confined 850 nm VCSEL
- 2010
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 46:14, s. 1014-1015
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 4. |
- Westbergh, Petter, 1981, et al.
(författare)
-
Higher speed VCSELs by photon lifetime reduction
- 2011
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819484895 ; 7952
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The impedance characteristics and the effects of photon lifetime reduction on the performance of high-speed 850 nm VCSELs are investigated. Through S 11 measurements and equivalent circuit modeling we show that the parasitic mesa capacitance can be significantly reduced by using multiple oxide layers. By performing a shallow surface etch (25 - 55 nm) on the fabricated VCSELs, we are able to reduce the photon lifetime by up to 80% and thereby significantly improve both static and dynamic properties of the VCSELs. By optimizing the photon lifetime we are able to enhance the 3dB modulation bandwidth of 7 μm oxide aperture VCSELs from 15 GHz to 23 GHz and finally demonstrate errorfree transmission at up to 40 Gbit/s.
|
|
| 5. |
- Westbergh, Petter, 1981, et al.
(författare)
-
Speed enhancement of VCSELs by photon lifetime reduction
- 2010
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 46:13, s. 938-940
-
Tidskriftsartikel (refereegranskat)abstract
- The dependence of the performance of high-speed 850 nm vertical cavity surface-emitting lasers (VCSELs) on photon lifetime is investigated. The photon lifetime is controlled by shallow surface etching. It is demonstrated that a reduction of photon lifetime by similar to 50% leads to a significant improvement of efficiency and speed. A record high 3 dB bandwidth of 23 GHz is achieved.
|
|
