APEXInsight: Over the next three years, 77% of airports and 71% of airlines areplanning major programs or R&D in biometric ID management to smooth curb-to-gatepassenger flow, according to SITA. But in order for implementation of airportbiometric solutions to keep pace with the growth of air travel, collaborationbetween stakeholders is key.

At last week?s SITA Euro Air Transport IT Summit inBudapest, straplined ?Aviation 5.0 ? Are You Ready??, the focus was on identitymanagement and passenger flow, with emphasis on the role of biometrics and itspotential to deliver a frictionless ?walkthrough? passenger experience wherebythe cumbersome checkpoints encountered in most airports today will becomeconsigned to the past.

?Secure and seamless travel is a must for the airtransport industry. It is encouraging to see that both airlines and airportsare investing in biometric technology to deliver a secure, paperless way toidentify passengers across multiple steps of the journey. We have already seengreat success where we have implemented it at airports across the world? saidBarbara Dalibard, CEO, SITA, referring to implementations of SITA Smart Path technology.

SITA Smart Path uses biometrics as the singleidentification token at every step in the passenger journey and integrates intoexisting airport infrastructure and airline systems such as check-in kiosks,bag drop units, gates for secure access, boarding and automated border control,helping airlines and airports comply with the various regulations fromgovernments and border agencies. Currently, the most common use of biometricsat airports is identity verification at self-service check-in kiosks ? alreadyin use at 41% of airports. SITA says that self-boarding gates using biometricswith ID documentation, such as a passport, will become ubiquitous over the nextthree years. Currently only 9% of airports have implemented this, according to SITA?s Air Transport IT Insights 2018 report, though aroundhalf expect to do so by 2021.

However, to realize the aspiration of a smoothbiometrically enabled passenger journey through the airport ? which isnecessary to keep pace with the growth of air travel, on track to double by2036 ? stakeholder buy-in across the ecosystem is vital.

From the airport operator?s perspective, ChristophSchneider, Masterplanner at Munich Airport, pointed out that passengers havemuch higher expectations with regards to the provision of contextualized andpersonalized services: ?No single travel stakeholder (airline, airports,hotels, agencies, corporations, etc.) has the capability to optimizeend-to-end-journey experience on their own. All stakeholders want and need thedata to provide relevant customer related service offers, but customer relateddata are fragmented in silos.? A framework is needed to share customer databetween any of the parties, ?with customers owning the data and consenting whatis shared with who, in line with data privacy laws, in a secure controlled wayand adhering to privacy concerns,? Schneider said.

Optics & Photonics News

Core Modulator Technology Shrinks to Chip Scale

Research News – Stewart Wills

Image: Harvard SEAS]

Electro-optic modulators, which convert electronic data to optical signals, are key components of long-haul telecom networks?and, for decades, lithium niobate (LN)modulators have constituted the workhorse technology. But these bulky,power-hungry devices have proved resistant to chip-scale integration. That has represented a stumbling block in the drive toward low-power, ultra-low-loss photonic circuits, not only for next-gen telecommunications but also for data-intensive conventional computing and quantum information processing.

Now, a search team led by OSA Fellows Marko Lon?ar of Harvard University and Peter Winzer of Nokia Bell Labs has devised a way to radically shrink both the size and the driving voltage of LN modulators (Nature, doi: 10.1038/s41586-018-0551-y).The result is a device 100 times smaller and 20 times more efficient than existing modulators?and one that’s poised for on-chip integration. The researchers envision a vast application space for the new modulators, both in high-bandwidth data communications and in reconfigurable optical circuits for other areas, ranging from microwave signal processing to photonic neural-network computing.

Voltage problems

Over the years, LN modulators have gotten the nod owing to the excellent electro-optical properties of lithium niobate. In particular, the symmetry characteristics inLN crystals leads to a strong Pockels effect (that is, to changes in the material’s optical properties in response to an applied electric field). Those material properties, in turn, mean that tiny applied voltage changes can alter the crystals’ refractive index, on ultra fast, femto second timescales.

The problem comes when you try to scale down the fountain-pen-sized LN modulators common in existing telecom networks into something that can fit on a chip.Because of fundamental challenges in etching wave guides into lithium niobate,current-generation NB modulators must rely on wave guides with relatively large mode sizes and poor light confinement. That shortcoming, which in turn imposes limitations on other design details, forces the modulators to operate at drive voltages of 3 to 5 V?well beyond the roughly 1-V levels required to play well with typical CMOS circuitry.

As a result, LN modulators have required electrical amplifiers that have kept their size and power consumption large?and researchers have looked to other materials, including silicon, indium phosphide, polymers and plamsonic surfaces, to develop chip-scale modulators. Unfortunately, none of these alternatives has put together the compelling package of electro-optic properties sported by LN modulators.

Etching LNwaveguides

The team behind the new work decided to take another crack at fashioning a chip-scale LN modulator. To do so, they drew on previous work in Lon?ar’s lab that took a fundamentally different approach to etching in lithium niobate (Optica, doi: 10.1364/OPTICA.4.001536).

In that previous work?which also involved the two co-lead authors of the current study, Cheng Wang (now at the City University of Hong Kong) and Mian Zhang?the team used a technique that involved laying down a single-crystal, 600-nm-thick thin LN film atop a CMOS-compatible insulating layer of SiO₂ on silicon. That easier-to-etch material combination, plus tweaks to optimize standard plasma etching processes, allowed the team to dry-etch low-loss LNsub wavelength wave guides and fashion them into high-quality microring resonators.

The integrated modulator consists of lithium niobate (LN) waveguides in aMach-Zehnder interferometer configuration. As electronic data flows into the modulator, changes in the surrounding electric field are converted to changes in refractive index in the waveguides due to LN’s strong Pockels effect,allowing an electronic data signal to be converted to an optical one. [Image:Courtesy of Second Bay Studios/Harvard SEAS]

For the new study, the team applied the same technique to creating integrated modulators in a traveling-wave Mach-Zehnder interferometer configuration, withLN wave guides acting as the interferometer arms. The wave guides run through dielectric gaps that, on an applied voltage, impose a microwave electric field of opposite sign on the two interferometer arms. That field, through thePockels effect in the lithium niobate, changes the optical phase in the two interferometer arms in an opposite sense?allowing the electrical voltage signal to be changed into an optical one.

?Smaller,faster and better”

Through their improved approach to etching lithium niobate, the researchers found that they were able to create a modulator only 1 cm long and 0.5 cm wide?100 times smaller than conventional LN modulators. The modulator required a driving voltage of only 1.4 V, within the range that it could be directly driven by aCMOS circuit, without bulky amplifiers. And the devices can support data transmission rates of up to 210 Gbit/s?with rates as high as a blistering 1Tbit/s a distinct possibility with more advanced modulator designs. ?It’s like Antman,” co-lead author Wang said in a press release. ?Smaller, faster and better.”

A key advantage of the new modulator, according to Peter Winzer, is that it will speed up progress toward moving optics and electronics closer on a single chip??paving the way toward future fiber-in, fiber-out opto-electronic processing engines,” he said. The result could be a variety of fast, low-loss photonic circuits and applications.

In a particularly intriguing note, the study concludes that the device’s advantages of low optical losses, good electro-optical response, integration and scalability could combine to help create ?a new generation of active integrated opto electronic circuits that can be reconfigured on a pico second timescale using attojoules of electrical energy.” The team believes those circuits could find use in microwave photonics, quantum networks, topological photonic circuits and photonic neural networks, among other areas.

The prospects have not been lost on Harvard’s Office of Technology Development?which, with Lon?ar’s lab, has created a start-up company,HyperLight, to ?commercialize a portfolio of foundational intellectual property related to this work.”

PublishDate: 27 September 2018