Application of Photonics

Optical interconnect systemsdefining the minimal requirements to the 2R
As data rates inside digital electronic systems areregenerator used, and several case studies using
increasing, the bandwidth of traditional copperexperimental data were investigated. A simulation
interconnects is increasingly limited by signal distortion,platform was developed making the extension to
power consumption, cross-talk and pin-out capacity.other regenerator configurations possible. It shows
Optical interconnects are viable alternatives as theythat if an appropriate regenerator is available, signal
offer higher bandwidth, lower cost and lower powermonitoring of any optical data signal should be
dissipation compared to traditional copperpossible.
interconnects.Sensor applications
To fully exploit the advantages of opticalOptical sensors are immune to electromagnetic
interconnects over their electrical counterparts at theinterference and can be used in harsh environments.
inter-chip level, it is necessary to introduce the opticalThey also provide good sensitivity, linearity and
access directly on the digital CMOS chip. This requiresstability. Commercial applications include physical
tight integration of optics with the digital CMOS chip.sensing (e.g. strain) and chemical or biological sensing.
A consortium of 10 companies has built a systemCurrently, most optical sensors are based on fiber
demonstrator, in which two-dimensional laser andoptics or free space optics, but INTEC's research
detector arrays are integrated on the CMOS chipdeals with integrating the sensor functions on
using flip-chip technology. Data between chips isphotonic ICs.
transported over a two-dimensional optical fiberA micro-fluidic flow cell is constructed so that
ferrule, which interfaces to the packaged chips withbiological samples can be flown over the sensor in a
optical access.controlled manner. The first tests for the sensing of
Also for future generation electronic circuits, opticalan avidin-biotin binding are accomplished. In
interconnect at the intra-chip level is very promising.collaboration with the Molecular Biology Group (UGent,
But to be acceptable to the microelectronics industry,VIB) and the Polymer Research Group (UGent) a
severe constraints are imposed on the design of thedesign for SOI multi-array sensors and their surface
optical interconnect layer. All fabrication steps shouldtreatment is made.
be compatible with future generations of electronicPHOTONICS
circuits and the total additional cost incurred shouldPhotonics is the science of generating, controlling, and
remain affordable. This means that as manydetecting photons, particularly in the visible and near
fabrication steps as possible should be wafer-scaleinfra-red spectrum, but also extending to the
processes. Therefore, investigating in the feasibility ofultraviolet (0.2 - 0.35 µm wavelength), long-wave
adding a photonic interconnect layer on top of siliconinfrared (8 - 12 µm wavelength), and far-infrared
ICs is done. This interconnect layer is fabricated by aTHz portion of the spectrum (e.g., 2-4 THz
combination of wafer bonding and wafer-scalecorresponding to 75-150 µm wavelength) where
processing steps. It is planar and will be built from atoday quantum cascade lasers are being actively
high-density passive optical wiring circuit integrateddeveloped. Photonics is an outgrowth of the first
with InP-based sources and detectors using a waferpractical semiconductor light emitters invented in the
bonding approach. SOI-waveguides allowing for veryearly 1960s at General Electric, MIT Lincoln
high-density wiring are being developed andLaboratory, IBM, and RCA and made practical by
fabricated using standard CMOS-processingZhores Alferov and Dmitri Z. Garbuzov and
techniques. The III-V epi-material for the activecollaborators working at the Ioffe Physico-Technical
photonic devices isInstitute and almost simultaneously by Izuo Hayashi
Telecommunication systemsand Mort Panish working at Bell Telephone
In the area of optical communications, work has beenLaboratories. Photonics most typically operates at
continued on tunable laser diodes and opticalfrequencies on the order of hundreds of terahertz.
regenerators, two components which are consideredJust as applications of electronics have expanded
keys for future all-optical networks. In the past newdramatically since the first transistor was invented in
types of widely tunable laser diodes has been1948, the unique applications of photonics continue to
successfully designed and characterized. This year,emerge. Those which are established as economically
attention has focused on the further optimization ofimportant applications for semiconductor photonic
those laser diodes and on their direct modulationdevices include optical data recording, fiber optic
behavior C11818, RP107telecommunications, laser printing (based on
Optical performance monitoring using asynchronousxerography), displays, and optical pumping of
signal histograms has proven to be very useful inhigh-power lasers. The potential applications of
numerous experimental setups. In research a signalphotonics are virtually unlimited and include chemical
independent asynchronous histogram constructionsynthesis, medical diagnostics, on-chip data
method using only a 2R regenerator and ancommunication, laser defense, and fusion energy to
adjustable attenuator, thereby avoiding complexname several interesting additional examples.
sampling systems and high-frequency electronics, is.
developed. A theoretical study was performed,