An adaptive wavelength tunable optical filter employing anangle-tuned interference filter and an intelligent digital controller

This paper describes an adaptive wavelength tunable optical filter, which is composed of an angle-tuned interference optical filter and an intelligent digital controller. The new angle-tuned interference filter consists of a dielectric interference optical filter and a piezoelectric angle-tuning mechanism. It achieves quick wavelength switching within 2.5 ms in a 30 nm tuning range and a sufficiently low crosstalk less than -30 dB. The intelligent digital controller has two functions: wavelength tracking and wavelength channel selection. Combining these technologies, we have developed a practical low-cost tunable filter suitable for a post-optical-amplifier filter in a high-sensitivity detection system and a channel selector in a WDM system that requires 10-100 ms channel selection time. With a wavelength tracking operation, we have confirmed -35 dBm high-sensitivity detection in 20 nm wavelength range in a 10 Gb/s system. We have also confirmed a wavelength channel selection operation within 18 ms in a three-channel wavelength division multiplexed (WDM) system whose channel spacing is 4.4 nm     

A 2.125-Gb/s BiCMOS fiber channel transmitter for serial datacommunications

A 2.125-Gb/s transmitter meeting the specifications of the emerging ANSI Fiber Channel standard has been developed using BiCMOS technology. This transmitter features (1) a fully bipolar 10:1 multiplexer (MUX) and a 2.125-GHz retimer for high-accuracy transmission of data, (2) an emitter-coupled logic (ECL) CMOS analog phase-locked loop, (3) pure ECL-level output for direct connection to the currently available optical modules, and (4) BiCMOS process technology that includes 0.25-μm CMOS devices and 20-GHz bipolar devices. The LSI serializes 32-bit-wide, 53.125-Mb/s data into 2.125-Gb/s data through a CMOS 8B10B encoder. The chip area is 3×2 mm², and the power dissipation is 860 mW     

Acceleration of Tri-Addition to [70]Fullerene by “Nanom Black” Fullerene Soot

We report the structure and properties of a fullerene soot called “Nanom Black,” which is prepared by removing fullerenes from the soot formed in fullerene production. Nanom Black remarkably accelerates the regioselective tri-addition of phenylcopper reagent to C₇₀, giving C₇₀Ph₃H at a reaction rate approximately 50-fold that in the absence of Nanom Black. Transmission electron microscopy, X-ray diffraction, and Raman data on Nanom Black are presented, and a mechanistic rationale is discussed.