SMART PIXEL ARRAYS(SPAs)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

SR ENGINEERING COLLEGEAnanthasagar, Warangal

CONTENTS:

Introduction Crux of a smart pixel array Components of SPA Applications Advantages Disadvantages Conclusion

What is a SMART PIXEL??

Smart pixels, the integration of photo detector arrays and processing electronics on a single semiconductor chip.

These are driven by its capability to perform parallel processing of large pixelated images and in real-time reduce a complex image into a manageable stream of signals

A smart-pixel array can be defined as a two dimensional array of optoelectronic devices that combines both optical inputs and outputs with electronic processing circuitry

WHY SMART PIXEL ARRAYS??

Smart pixel arrays hold great promise as an enabling technology for board-to-board interconnections in digital system.

For taking advantage of the high space-bandwidth product of optics , optically interconnected two dimensional arrays of smart pixel have emerged as an attractive interconnection platform.

SPAs as an emerging optoelectronic technology is crucial to meet g performance needs in high-speed switching ; optical interconnects in computers, and flat-panel display applications

VERTICAL-CAVITY SURFACE-EMITTING LASERS (VCSELS)

The Vertical Cavity Surface Emitting Laser (VCSEL) is a very important and useful light source.

The figure shows a very simple depiction of a VCSEL showing the substrate, layers of GaAs and AlAs that form the Bragg planes, the quantum well region where gain occurs, the p and n doped regions that make the p.n. diode junction

COMPONENTS OF SPA:

• OPTICAL DECODER• PROCESSING

ELEMENTS• I/O PINS• VCSEL DRIVERS• PHOTO DETECTOR

ARRAY

PROCESSING ELEMENTS:

• Each PE is a 1-bit wide processor that can operate at 20 MHz and consists of an arithmetic logic unit, a logic circuit which can perform 16 logic functions, a full adder, a 32-bit shift-register, 6 static registers, and some control circuits.

• Although the PEs are capable of general purpose processing, they were designed with FFT processing in mind.

Applications of SPAs

SPAs have an umpteen No. of uses in the field of image processing ,data processing ,digital signal processing

Many applications requiring high performance image capturing use SPAs, which integrate very special functionslity at the pixel level.

The 3D image sensors consisting of SPAs are to evaluate size , shape and volume in industrial automation applications

SPAs are also used for optical data interconnect and optical memory access.

Microscopic topographer 3D Image sensor

Mega pixel high speed camera

ADVANTAGES OF SPAS:

• Smart pixel arrays provide high data transmission rates through high speed switching

• Smart pixel arrays provide decreased cross talk ,by virtually eliminating interference phenomenon

• Smart pixel inter connects are lighter as they are made of feather-light fiber ribbons when compared to today’s copper wires

• Smart pixel arrays provide high processing speeds by consuming significantly less optical power.

DISADVANTAGES OF SPAS:

• The greatest challenge being faced by smart pixel technology is economic

• There exists potential problems in getting the electrical design to interact with the optics

• The low efficiency of photo detectors results in reduced switching speed thus decreasing the data transfer rate.

• Non-uniformity may result due to fabrication imperfections

CONCLUSION:

Thus Smart pixels, the integration of photo detector arrays and processing electronics on a single semiconductor chip, have been driven by its capability to perform parallel processing of large pixelated images and in real-time reduce a complex image into a manageable stream of signals that can be brought off-chip. Data retrieval rates could improve by orders of magnitude, depending on the size of the smart pixel arrays