6 December 2012
OPEL subsidiary ODIS produces integrated laser device using POET monolithic optoelectronic platform
OPEL Technologies Inc of Toronto, Ontario, Canada says that its US affiliate OPEL Defense Integrated Systems (ODIS Inc) of Storrs, CT has produced an integrated laser device, achieving a key milestone in its Planar Optoelectronic Technology (POET) process, which enables high-performance devices fusing optical and electronic devices together on a single chip.
The firm reckons that, by allowing the production of components with increased speed, density, reliability and lower costs, POET offers the semiconductor industry the ability to push Moore’s Law to the next level, overcoming existing silicon-based bottlenecks, and potentially changing the roadmap for a broad range of applications such as smartphones, tablets and wearable computers.
OPEL says that, after years of development, it has succeeded in fabricating the first Vertical Cavity Laser (VCL) using ODIS’ patented POET GaAs III-V technology. The firm adds that incremental progress over the years has led to what many consider to be the next phase of semiconductor development, i.e. surpassing the capabilities of complementary metal oxide semiconductor (CMOS) technology for the next generation of high-speed low-power applications, CMOS technology advances are now widely believed to have reached a saturation point.
The new laser can serve as the basis for chip-to-chip interconnection, and complements other optoelectronic devices already demonstrated by ODIS, including heterostructure field-effect transistors (HFETs), optical thyristors, pulsed lasers, and super-radiant light emitting devices (which can all be monolithically fabricated via the POET process).
“Dr Taylor and the ODIS team have chosen to achieve the most difficult laser first and have done so under extreme duress,” comments Peter Copetti, executive director of OPEL’s board. “This is not just an endorsement of the ODIS team but also of the POET process itself,” he adds.
“The re-set of our milestone timelines by approximately 8 weeks because of equipment repair caused by Hurricane Sandy is obviously a disappointment to everyone involved, but we believe it is merely a bump in the road,” Copetti continues. “In the long run, it should have no material impact on monetizing POET.” OPEL’s chief scientist Dr Geoffrey Taylor adds that,“POET remains on track with its vision of full monolithic integration and its applications in microprocessing”.
POET merges optical devices into the growth and fabrication that supports complementary HFET analog and digital functions. The n-channel and p-channel FETs take advantage of the high mobilities inherent to strained quantum wells. Simultaneously, the quantum wells provide the active emitter for lasers and amplifiers and the active absorber for detectors and modulators.
The intimate connections between diverse device types enables novel gate designs that dramatically reduce the power consumed in opto-electronic (OE) and electro-optic (EO) conversion, it is claimed. The VCL also has the small footprint required for dense circuit layout and enables vertical connections from anywhere in the circuit plane to fiber or to other stacked chips. Further, the same VCL structure enables both in-plane and edge-emitting operation, based on proprietary OE designs. The firm reckons that availability of the integrated VCL can change the architecture and design for future complementary integrated circuits.
Future technology development aims to lower the threshold current, increase the output power and optimize the in-plane version of the VCL. In addition, the complementary transistor circuit capability will be enhanced by reducing the feature size to the 100nm scale, incorporating ODIS’ new self-aligned contact technology. With transistor cutoff frequencies of about 38GHz for a 0.7μm gate, scaling is expected to produce 260GHz transistors with commensurate improvements in circuit speed.
In the near-term, POET is expected to include an optical interface as a single chip to connect existing CMOS processors. The optical interface chip integrates the laser, modulator, modulator driver, detector, receiver amplifiers, serializer/deserializer, clock & data recovery, and phase-locked-loop circuits monolithically.
The longer-term solution would look to replace CMOS gates with POET complementary HFET gates. POET processors would provide their own optical output and also perform the optical receive function, hence the need for a separate interface chip would no longer be required.
“This is a key milestone in our acceleration of POET for commercial application,” notes OPEL’s CEO Leon M. Pierhal. “OPEL now has all components in place for on-chip integration of photonic circuits in the same semiconductor framework as electronic circuits,” he adds.
“Hurricane Sandy's effect was felt at ODIS’ R&D facility at the University of Connecticut,” continues Pierhal. “Equipment damage within the facility caused by Sandy made the recovery from the storm and the completion of the VCL extremely difficult,” he adds. “The damage inflicted on the delicate equipment must now be effectively and permanently addressed in order to continue with POET's milestone achievements. A rebuild and retrofitting period of 6-8 week is being planned for December and January, which will delay the rollout planning process.”
The POET platform is currently the basis for a number of key ODIS commercial and military projects, including optical code division multiple access (OCDMA) devices for avionics systems, combined RF/optical phased arrays, optoelectronic directional couplers, and ultra-low-power random access memory (RAM).