We propose and demonstrate a type of broadband light source (BLS) based on mutually injection-locked Fabry-Perot laser diodes (F-P LDs). By mutually injection-locked F-P LDs, we realized a BLS with flatness and multimode output spectrum. The proposed BLS generates a 100GHz spaced optical frequency comb with fifteen modes, ranging from 1532 to 1544nm with a flatness of < 4dB. Consequently, the mutually injection-locked F-P LDs light source could be relatively simple and cost-effective compared with other demonstrated light source schemes.
A chaotic wireless communication system is described that is based on collective synchronization among wireless nodes. Chaotic synchronization was first investigated by numerically analyzing the collective behavior of wireless nodes, each having Chua's circuit as a chaos generator. The condition required to achieve synchronization among three nodes was estimated using numerical analysis. Numerical simulation demonstrated the possibility of chaotic synchronization among many wireless nodes and the possibility of formation of node clusters through chaotic synchronization. This study will open new research areas for chaotic communications and complex networks.
We investigate the new method to evaluate the absorption spectrum by using the scattered light spectrum. The measurement set-up is to prevent the direct reflection light. By subtracting the two spectra, we can evaluate the change in the absorption spectra of samples where the transmitted light spectrum can not easily be measured. We apply this method to the derivation of absorption spectrum of flowers' petals, and estimate what kinds of absorption spectra contribute to the color of flowers' petals.
A novel design for a high-speed divide-by-3/4 counter is presented. The proposed design reduces not only the critical path delay but also the feedback path delay, hence it can increase the operating speed. With this divide-by-3/4 counter, a divide-by-127/128 dual-modulus prescaler (DMP), implemented in 0.18µm CMOS technology, shows a maximum operating frequency of 7.0GHz with 2.4mW power consumption at 1.8V supply voltage, which has 25% speed improvement and still consumes less power as well compared to the recently-reported one.
In MTCMOS, the circuit state should be preserved for state retentive sleep, and the virtual power/ground rails clamp (VRC) scheme is an effective method for this purpose. Our approach realizes the voltage clamp function without additional devices like diodes, by feeding the virtual ground voltage back into a sleep signal. There are also other effects; cutting off the leak current of the sleep buffer, and charge recycling of sleep signal node. We have achieved a 19.7% lower power consumption and a 5.4% cell area reduction.