F. Mederer

3-Gb/s data transmission with GaAs VCSELs over PCB integrated polymer waveguides

GaAs quantum-well (QW)-based vertical-cavity surface-emitting lasers (VCSELs) at 855-nm emission wavelength are investigated for intraboard polymer waveguide links. We report a 3-Gb/s pseudorandom bit sequence (PRES) nonreturn-to-zero (NRZ) data transmission over about 5-cm long printed circuit board (PCB) integrated multinode polymer waveguide arrays of two different geometries at bit-error rates (BERs) of less than 10/sup -11/.

Single-mode VCSELs

We compare various approaches aiming at large-area high-power single-mode oxidized VCSELs. Stable and reproducible single-mode emission with SMSR (side-mode suppression ratio) greater than 30dB and output powers well above 5mW are reported for the long monolithic cavity and self-aligned shallow surface etching approaches, both of which are suitable for commercial production. Additionally, Photonic Crystal Surface-Emitting Lasers (PCSELs) are introduced, which enable advanced mode control by novel transverse optical guiding techniques.

Large-Area Single-Mode Selectively Oxidized VCSELs: Approaches and Experimental

We present the investigation of several methods to increase the active diameter of single transverse mode oxide confined VCSELs in both the 850 and 980 nm wavelength regimes. Among the concepts considered are mode intensity specific shallow surface etched reliefs, monolithically increased cavity lengths, current confinement matching the fundamental mode intensity distribution and saturable absorbers. All approaches are introduced in theoretical considerations and corresponding measurement results are presented. Additionally, numerical simulations are performed to gain an increased understanding of some of the mode selection mechanisms. The considered concepts are evaluated in terms of decrease of the series resistance (for impedance matching/driving reasons) and device lifetime (as derived from maximum current densities). The results obtained are also compared to other approaches found in literature (e.g. metal apertures, photocurrent feedback, Fabry-Perot etalon, half-symmetric cavity). Conventional devices with optimized thin oxide aperture location have shown single-mode output powers above 4 mW with an active diameter of 3.5 micrometer. A record high single-transverse mode output power of 5 mW at a series resistance of 98 (Omega) is obtained for a 7 micrometer aperture device by increasing the cavity length monolithically by 4 micrometer.

Multi-Gb/s graded-index POF data link with butt-coupled single-mode InGaAs VCSEL

InGaAs quantum-well-based vertical-cavity surface-emitting lasers (VCSELs) at 935-nm emission wavelength are investigated for perfluorinated graded-index plastic-optical fiber (GI-POF) links. We report a 7-Gb/s pseudorandom bit sequence (PRBS) nonreturn-to-zero (NRZ) data transmission over 80-m-long 155-/spl mu/m-diameter GI-POF at a bit-error rate (BER) of better than 10/sup -11/.

GaAs VCSEL's at /spl lambda/=780 and 835 nm for short-distance 2.5-Gb/s plastic optical fiber data links

Selectively oxidized GaAs vertical-cavity surface-emitting lasers for /spl lambda/=780- and 835-nm emission wavelength and 120-/spl mu/m-core diameter step index plastic optical fiber (POF) are investigated for short distance interconnects. 2.5-Gb/s pseudorandom data transmission over up to 2.5 m of plastic fiber is demonstrated with a bit-error rate (BER) of better than 10/sup -11/. Furthermore, bias-free data transmission at 2.5 Gb/s over 1-m fiber length again at a BER of better than 10/sup -11/ is reported.

Biased and bias-free multi-Gb/s data links using GaAs VCSELs and 1300-nm single-mode fiber

Selectively oxidized single-mode GaAs vertical-cavity surface-emitting lasers are investigated for biased 3-Gb/s and bias-free 1-Gb/s data links. Bit-error rates of better than 10/sup -11/ for pseudorandom data transmission over 4.3 km of standard 1300-nm single-mode fiber are demonstrated. A simple mode filter is used to suppress intermodal dispersion. The requirements of the gigabit ethernet are fulfilled even for bias-free operation.

10 Gb/s data transmission with TO-packaged multimode GaAs VCSELs over 1 m long polymer waveguides for optical backplane applications

Abstract TO-packaged GaAs vertical-cavity surface-emitting lasers (VCSELs) are being investigated for high-bit-rate data transmission over 103 cm of a 250×200 μm 2 core size polymer-based optical waveguide to be employed in optical backplanes. The bit-error rates for 5 and 10 Gb/s transmission over the waveguides incorporating 45° deflection mirrors are better than 10−12. For the first time, the measured bandwidth-length-product for a polymer-based optical backplane exceeds 10 GHz × m .

Polymer optical waveguides integrated in printed circuit boards

Temperature stable polymer optical waveguides have been realised and integrated into printed circuit boards (PCB). A special waveguide fabrication process based on hot embossing has been developed which is compatible with standard PCB processing technologies.

High performance selectively oxidized VCSELs and arrays for parallel high-speed optical interconnects

High-bandwidth single-mode selectively oxidized vertical-cavity surface-emitting laser (VCSEL) arrays operate at 980 nm or 850 nm emission wavelength for substrate or epitaxial side emission. Coplanar feeding lines and polyimide passivation are used to reduce electrical parasitics in top-emitting GaAs and bottom-emitting InGaAs VCSELs. To enhance fundamental single-mode emission for larger devices of reduced series resistance a surface relief transverse mode filter is employed. Fabricated VCSELs are applied in various interconnect schemes. InGaAs quantum-well based VCSELs at 935 nm emission wavelength are investigated for use in perfluorinated graded-index plastic-optical fiber (GI-POF) links. We obtain a 7 Gb/s pseudo random bit sequence (PRBS) nonreturn-to-zero (NRZ) data transmission over 80 m long 155 /spl mu/m diameter GI-POF. We investigate data transmission over standard 1300 nm, 9 /spl mu/m core diameter single-mode fiber with selectively oxidized single-mode GaAs and InGaAs VCSELs. We achieve biased 3 Gb/s and bias-free 1 Gb/s pseudo-random data transmission over 4.3 km at 830 nm emission wavelength where a simple fiber mode filter is used to suppress intermodal dispersion caused by the second order fiber mode. For the first time, we demonstrate 12.5 Gb/s data rate transmission of PRBS signals over 100 m graded-index multimode fiber or 1 km single-mode fiber using high performance single-mode GaAs VCSELs of 12.3 GHz modulation bandwidth emitting at /spl lambda/=850 nm.

12.5 Gbit/s data rate fiber transmission using single-mode selectively oxidized GaAs VCSELs at /spl lambda/=850 nm

We report 12.5 Gbit/s data transmission over 100 m multimode fiber (MMF) and 1 km single-mode fiber (SMF) using single-mode selectively oxidized GaAs VCSELs emitting at 850 nm. In both cases the bit-error rate (BER) remains better than 10/sup -11/ for pseudo-random bit sequence (PRBS) transmission. The obtained results clearly indicate that GaAs VCSELs are attractive transmitters for high speed fiber optic interconnects. A schematic of the selectively oxidized top emitting GaAs VCSEL is shown-the one-wavelength thick inner cavity contains three active GaAs-Al/sub 0.2/Ga/sub 0.8/As quantum wells.