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We present active components developed in imec's silicon photonics platform that enable 50-Gb/s non-return-to-zero operation using CMOS compatible voltages. [ABSTRACT FROM PUBLISHER]

We demonstrate 100-Gbps silicon-contacted germanium waveguide p-i-n photodetectors integrated on imec's silicon photonics platform. The performance of 14 and 20 μm long devices is compared. The responsivity of the devices is 0.74 and 0.92 A/W at 1550 nm, respectively. [ABSTRACT FROM PUBLISHER]

Short-range parallel optical interconnect between integrated circuits can alleviate bandwidth, power, and packaging density issues that are associated with low-latency high-bandwidth input-output over electrical interconnect. In this paper, we evaluate the option of using true source-synchronous signaling over optical interconnect with a large number of channels, reducing the substantial per-channel clock synchronization circuitry to one instance. We also look into dc-unbalanced signaling to remove the need for data coding. Uniformity across channels is key to the feasibility of such an approach. An actual 64-channel parallel optical interconnect setup at 1.25 Gb/s/channel is examined, and models for the performance and uniformity of the different constituent parts of the interconnect are drawn up. Major attention is given to the statistical modeling of the coupling efficiency between a vertical cavity surface emitting laser array and a multifiber connector. Although derived in the context of a uniformity study, the stochastic models and the modeling approach are valuable in their own right. In our case study, the usage of a common logic threshold across all channels, which is required for dc-unbalanced signaling, appears infeasible after all models are combined. Efficient true source-synchronous signaling turns out to be within reach in carefully designed systems. [ABSTRACT FROM PUBLISHER]

We have performed a numerical study involving the design and optimization of InP-based microdisk lasers integrated on and coupled to a nanophotonic silicon-on-insulator (SOI) waveguide circuit, fabricated through bonding technology. The theoretical model was tested by fitting it to the lasing characteristics obtained for fabricated devices, which we presented previously. A good fit was obtained using parameter values that are consistent with numerical simulation. To obtain optimized laser performance, the composition of the InP-based epitaxial layer structure was optimized to minimize internal optical loss for a structure compatible with efficient current injection. Specific attention was paid to a tunnel-junction based approach. Bending loss was quantified to estimate the minimum microdisk diameter. The coupling between the InP microdisk and Si waveguide was calculated as function of the bonding layer thickness, waveguide offset and waveguide width. To study the lateral injection efficiency, an equivalent electrical network was solved and the voltage-current characteristic was calculated. Based on these results, the dominant device parameters were identified, including microdisk thickness and radius, coupling loss and tunnel-junction p-type doping. These parameters were optimized to obtain maximum wall-plug efficiency, for output powers in the range 1-100 W. The results of this optimization illustrate the potential for substantial improvement in laser performance. [ABSTRACT FROM PUBLISHER]

A multichannel free-space microoptical module for dense MCM-level optical interconnections has been designed and fabricated. Extensive modeling proves that the module is scalable with a potential for multi-Tb/s·cm2 aggregate bit rate capacity while alignment and fabrication tolerances are compatible with present-day mass replication techniques. The microoptical module is an assembly of refractive lenslet-arrays and a high-quality microprism. Both components are prototyped using deep lithography with protons and are monolithically integrated using a vacuum casting replication technique. The resulting 16-channel high optical-grade plastic module shows optical transfer efficiencies of 46% and inter-channel cross talks as low as -22 dB, sufficient to establish workable multichannel MCM-level interconnections. This microoptical module was used in a feasibility demonstrator to establish intra-chip optical interconnections on a 0.6 μm CMOS optoelectronic field programmable gate array. This optoelectronic chip combines fully functional digital logic, driver and receiver circuitry and flip-chipped VCSEL and detector arrays. With this test-vehicle multichannel on-chip data-communication has been achieved for the first time to our knowledge. The bit rate per channel was limited to 10 Mb/s because of the limited speed of the chip tester. [ABSTRACT FROM PUBLISHER]

An 8×8 array of resonant-cavity light emitting diodes (RCLED's) emitting at 980 nm and flip-chip mounted onto complimentary metal-oxide-semiconductor (CMOS) integrated drivers, is presented. The RCLED's are optimized for maximal extraction efficiency into the numerical aperture of polymer optical fibers (NA=0.5) and minimal optical crosstalk. Design of the optimal cavity structure is presented, and 8×8 arrays are realized and mounted directly onto standard CMOS chips using a solder reflow technique. The CMOS integrated drivers are designed for high-speed operation and low-power consumption, and are realized in 0.8 and 0.6-μm CMOS technology. The electrooptical modules have been realized and characterized, and over 50-μW optical power coupled to POF at 3-mA drive current is reported. Open eye diagrams at operation speed up to 250 Mb/s are presented. These characteristics are compatible with CMOS integrated low-power receivers [ABSTRACT FROM PUBLISHER]