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There are many systems to include humans in the mechanical control loops. In such systems, low-skilled operators are considered to cause accidents. To prevent these kinds of accidents, analysis of human's model with various methods has been studied. “Crossover model” is well known as one of the models to analyze human-machine systems. However, many of those researches have analyzed humans when they...
We propose a novel multi-channel radio-on-fiber signal generation technique, using a reciprocating optical modulator. Each component can be individually modulated by a millimeter-wave.
This article proposes two types of simple disturbance observers for friction compensation. The proposed observers are based on the LuGre friction model. One observer directly uses the LuGre model as a design base, where the LuGre model is locally linearized and observer gains are derived from the linearized model. The other one is based on a type-1 disturbance observer with the LuGre model. In the...
In this paper, we propose a control method to swing up and stabilize a double Furuta pendulums (DFP).The DFP is a rotational type inverted pendulum system that has a base-link and two pendulums of different length at the both ends of the base-link. The proposed method consists of three controllers for the DFP, i.e., a swinging up controller for a long pendulum, a controller to keep a long pendulum...
This paper proposes a swinging-up and stabilization method for inverted pendulums based on a pendulum oscillation model. A normalized oscillation model is derived by using only one model parameter, i.e., the natural frequency of a pendulum. As a control strategy, energy-based control with a normalized energy model is utilized for the swinging-up from the pendant position. For the stabilization of...
We proposed and experimentally investigated a frequency swapping technique for two lightwaves by using a LiNbO3 optical switch where only Mach-Zehnder structures were nested. 10-GHz opposite frequency shifts for two lightwaves were successfully obtained.
We have successfully fabricated a polarization converter by reversing the polarity of the electrode in coherence length along a X-cut Z-propagating Ti:LiNbO3 waveguide. 100% conversion ratio was achieved with an applied voltage of 17 V.
Guard-time-free output port switching is demonstrated by using a LiNbO3 optical switch possessing rapid response and high extinction ratio. Evaluated maximum power penalty was 1.2 dB for error-free operation of the switch.
We investigated optical packet signal distortion due to crosstalk of an optical switch by adopting an intensity trimming technique. Less than -17 dB is required for error-free operation.
We demonstrate highly pure 160-GHz two-tone lightwave generation using a high extinction-ratio optical intensity modulator and a delay interferometer. The undesired sideband suppression ratio was more than 39 dB.
Internet access is ubiquitous throughout the developed and much of the developing world. Many users, especially youthful ones, regard broadband video applications, such as social networks, games and IP movies, as necessities. Innovative developments in broadband access technologies hold the key to enhancing these services and realizing futuristic applications. For example, the need for much higher...
Advances in telecommunication and information technologies are fueled by innovations resulting from strategic research. Strategic research may be defined as that mission-oriented research which pursues specific and realistic goals leading to practical applications. Photonic integration, a research activity since the beginnings of optical communication over 35 years ago, with the goal to reduce packaging...
We present a high-speed dual-parallel Mach-Zehnder modulator with thin substrate. Modulator frequency response was investigated by network analyzer and optical spectrum analyzer based techniques. Clear eye opening was achieved at 87 Gbaud with on-off-keying.
We study the impact of modulator extinction-ratio on duobinary signal generation. Duobinary transmission with 2 % modulation depth was achieved at 10 Gb/s, where the extinction-ratio was enhanced by an active trimming technique.
The present article argues that mirative markers are describable as the speaker’s confirmation of the relevant event conception that lies in or comes into his or her assumption (the immediate scope of predication). Mirativity can consist of at most three elements: (i) ‘the relevant event conception’s coming into the speaker’s assumption from either inside or outside his/her mind’ (UNEXPECTEDNESS),...
Crosstalk in a balanced bridge interferometric-type optical switch is highly suppressed by using Mach-Zehnder (MZ) structures as intensity trimmers. An imbalance in optical power is caused by deviations from the ideal dividing ratio of directional couplers in the switch, which causes an increase in the crosstalk. This imbalance was compensated for by adjusting the transmittances of the nested MZ structures...
Devices for rf/light signal conversions are very essential to build various microwave photonics systems. Among variety of photonic devices for MWP systems, the present talk will be focused especially on devices based on electrooptic modulation.
This paper discusses the possibility of applying the high extinction ratio Mach-Zehnder LiNbOs optical modulator to a high stability and high frequency (over 100 GHz) optical reference signal generator for Astronomical Radio Interferometer. ALMA (Atacama Large Millimeter/sub-millimeter Array) is a high-frequency radio interferometer array currently under development, and each of the ALMA antennas...
We demonstrate that dc extinction ratio can be improved by reducing polarization crosstalk in high-extinction-ratio LiNbO3 optical intensity modulator. Observed improvement was more than 25 dB for the modulator used in the experiment. However, for double sideband suppressed carrier modulation, other factor limits carrier-to-sideband ratio.
We propose and demonstrate ultra-flat frequency comb generation using a "push-pull" operated Mach-Zehnder modulator (MZM), where the MZM is dual driven with out-of-phase signals having different amplitudes. 10-GHz spaced 210-GHz-wide comb is flatly generated.
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