TOKYO, Feb. 14, 2006 -- NEC Corp. said it has developed fundamental silicon (Si) nanophotonics technology that boosts optical data transmission in large-scale integration (LSI) chips by eliminating bottlenecks. The company presented its development at ISSCC (International Solid-State Circuits Conference) 2006, held last week in San Francisco.
NEC said the new technology reduces the footprint area for the optoelectronic signal transfer function down to 10 microns square -- small enough to set onto an LSI chip -- by combining an ultrasmall amplifier with an existing Si nanophotodiode.
"Application to an optical wavelength division multiplexing system enables transmission of a significantly larger amount of data, compared to conventional copper wiring, through an optical wire with a width of less than one micron," the company said in a statement. "Both of these developments have significantly increased the possibility of realizing optical data transmission and high-frequency optical clock distribution on LSI chips."
Typically, the operating speed of an LSI chip has been accelerated by increasing the clock rate through miniaturization of transistors, NEC said. Recently, however, LSI manufacturers have found it difficult to increase clock speed without simultaneously increasing power consumption, due to the growing leakage current of transistors as miniaturization advances. To overcome this problem, NEC developed a multicore technology that enables the suppression of clock speed in an LSI chip through parallel processing. This technology has already been commercialized by NEC as an application processor, MP211, for mobile handsets. However, the company said, by 2015, the data transfer rate for a microprocessor (MPU) is expected to exceed one terabit per second -- 10 times higher than current rates -- and to cause difficulty in conventional electrical wiring in high-performance information and network systems.
"Thus, there is a great need for novel data transfer technology that employs light (optical wiring technology)," it said.
NEC used the small electrical capacitance of nanophotodiode (junction capacitance of about 10 aF) to reduce the footprint of the high-speed amplifier by approximately two orders of magnitude. A high-speed optoelectrical signal transfer was carried out with little power consumption by combining the circuit and the nanophotodiode.
The company said it is developing technology for realizing ultrasmall optica multiplexers/demultiplexers with a size of about 100 microns square, about one-hundredth the size of conventional devices, with an ultrafine optical waveguide; and ceramic electro-optic film fabrication, using an aerosol deposition method, to reduce the size of optical modulators, which change electric signals into optical signals, to 100 microns -- about one-tenth the size of conventional devices.
"These technologies greatly increase the possibility of incorporating into LSI chips optical wires that can realize data transfers 100 times greater than current copper wires with low power and high speed," it said.
NEC said its elemental Si nanophotonics technology and new circuit technology "will contribute substantially to the sophistication of computers and servers, in addition to the miniaturization of network devices and the development of network components with high endurance for electromagnetic noise."
Part NEC's research was commissioned by the New Energy and Industrial Technology Development Organization under Japan's Ministry of Economy, Trade and Industry as part of its Nano Structure Forming for the Advanced Ceramic Integration Technology Project.
For more information, visit: www.nec.com