Performance-limiting asymmetric distortion is observed in the spectra of fundamental pulses transmitted through GaAs-Al(0.9)Ga(0.1)As multilayer waveguides designed for surface-emitted second-harmonic generation. This behavior is attributed to refractive-index changes resulting from the accumulation of free carriers created by two-photon absorption in the GaAs layers. Numerical simulations of the intensity-dependent spectra by use of the separately measured two-photon absorption coefficient are shown to be in good agreement with the observed spectra.

We present our work in the area of heterogeneous optical integration, where separately manufactured electronic components are assembled on to an active silicon photonics interposer to form a higher-level component. This process allows for the integration of components independently designed and optimized from several different technology and foundry platforms onto a common interposer. Heterogeneous integration is essential for manufacturing higher speed and performance components. Higher levels of integration also allow for closer placement of devices which minimizes the parasitic power consumed to compensate for the frequency dependent losses in the interconnect traces.

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To meet the insatiable demand for data bandwidth in VSR (very short reach up to 300m) applications including server and routers, parallel optical interconnection offers a promising solution in terms of performance and cost effectiveness. A 12-channel pluggable paralle optical transmitter module has been developed to achieve a data rate of 2.5 Gb/s per channel. To maintain the robustness of the optical signal integrity under different environmental conditions, the thermal management is crucial. In this paper the thermal performance evaluation of the optical module was carried out through both numerical simulation and experimental verification. The optical module mainly consists of a VCSEL (vertical cavity surface emitting laser) array, a driver IC and a heat sink. Three types of heat sinks were integrated into the transmitter module separately. The thermal environments used for this evaluation include the normal and high ambient temperature, and both still-air and forced-air conditions. The ambient temperature and the wind speed were controlled by using a Wind Tunnel. The simulation was performed by using a CFD (computational fluid dynamics) program. In all the three modules, the simulation and experimental results of the junction temperature have shown good agreements. For Module 1 under the high ambient temperature, a forced-air condition was required to keep the junction temperature below 70°C. For Module 2 and Module 3, the junction temperature can be controlled below 70°C even under the high ambient temperature without using a fan.

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