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Polarisation switching in vertical-cavity surface-emitting lasers: from experimental observations to applications

Verschaffelt G., Panajotov K., Albert J., Nagler B., Peeters M., Danckaert J., Veretennicoff I., Thienpont H.

Opto-Electronics Review

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2001

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Vol. 9, No. 3

257-268

EN

Touted as promising components for present and future data-communication and sources for photonic switching fabrics, vertical-cavity surface-emitting lasers (VCSELs) have been studied in detail during the past years, with a focus on their static light-current and dynamic intensity modulation characteristics. Their superior beam quality, low power consumption, Gigahertz modulation bandwidth and the possibility of manufacturing these devices in 2D arrays are often cited as substantial advantages compared to traditional edge-emitting semiconductor lasers or light emitting diodes. A disadvantage of VCSELs is that the polarisation of the emitted light is not defined a priori due to the VCSEL’s quasi-cylindrical symmetry and its direction of lasing perpendicular to the active region. However, real VCSELs do emit linearly polarised light and often polarisation switching from one state to the orthogonal one is observed as the current is changed. In this contribution we will discuss the experimental characteristics of this intriguing polarisation switching phenomenon. We will give an overview of various physical mechanism proposed to explain the polarisation behaviour of these devices and we will illustrate the use of this polarisation switching in the implementation of reconfigurable optical interconnects.

2

Photonic systems for local image processing

Buczyński R., Viet K. B., Szoplik T., Veretennicoff I., Thienpont H.

Opto-Electronics Review

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2001

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Vol. 9, No. 3

215-228

EN

Local image processing is about performing a basic group of simple arthmetic and logic operations an a limited neighbourhood of very pixel in 2 D-represented data. The parallel architecture of optoelectronic processors makes these machines especially well suited to perform such local operations. In this paper we present some possible architectures of such processors and a proof-of-principle demonstrator based on present-day technology. We discuss applications and highlight limitations.

3

Free-space micro-optical modules: the missing link for photonic interconnects to sillicon chips

Thienpont H., Baukens V., Volckaerts B., Ottevaere H., Debaes C., Vervaeke M., Tuteleers P., Vynck P., Hermanne A., Hanney M., Brunfaut M., Van Campenhout J. M., Veretennicoff I.

Opto-Electronics Review

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2001

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Vol. 9, No. 3

238-247

EN

We report on design, fabrication, characterisation, and demonstration of scalable multi-channel free-space intercinection components with the potential for Tb/s cm² aggregate bit rate capacity over inter-chip interconnection distances. The demonstraton components are fabricated in a high quality optical plastic, PMMA, using an ion-based rapid prototyping technology that we call deep proton lithography. With the presently achieved Gigabit/s data rates for each of the individual 16channels with a BER smaller than 10⁻¹³ and with inter-channel cross-talk lower than -22 dB the module aims at optically interconnecting 2D opto-electronic VCSEL and receiver arrays, flip-chip mounted on CMOS circuitry. Furthermore, using ray-tracing software and radiometric simulation tools, we perform a sensitivity analysis for misalignment and fibrication errors on these plastic micro-optical modules and we study industrial fabrication and material issues related to the mass-replication of these components through injecton-molding techniques. Finally, we provide evidence that these components can be mass-fabricated in dedicated, highly-advanced optical plastics at low cost and with the required precision.

4

Functional properties of dual-rail photonic image processor using comparator arrays

Buczyński R., Szoplik T., Jankowski S., Veretennicoff I., Thienpont H.

Optica Applicata

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2001

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Vol. 31, nr 2

453-465

EN

We extend the description of a discrete-time cellular neural network, depicting the behaviour of both cellular and morphological processors, to any type of dual-rail processors. We show that a system with two arrays of differential pairs of transceivers can be treated as a two-layer cellular network and that it can perform morphological and rank order filter operations. As an illustration we built and tested a dual-rail processor composed of arrays of GaAs optical thyristor differential pairs and highlight experimental results on median filtering