Isao Morohashi

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Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a probabilistic process, and hence occurs at a limited rate, which restricts wider applications of Q-ICT. To(More)
— We are developing a low noise heterodyne receiver at 3THz band for applications of atmospheric and astronomical research and for application of wireless communications. We have developed a phase-locking system of a terahertz quantum cascade laser (THz-QCL) by using a hot electron bolometer mixer. The THz-QCL was locked to terahertz reference generated by(More)
A highly integrated 40Gbit/s coherent optical receiver is reported using a Costas loop as a homodyne optical phase locked loop (OPLL). A photonic IC, an electrical IC, and a hybrid loop filter are characterized, and the feedback loop system is fully analyzed to build a stable homodyne OPLL. All components are integrated on a single substrate within the(More)
—Adaptive digital modulation in the optical domain is performed using an integrated optical modulator with a high symbol rate of 10 Gbaud. The optical digital-to-analogue conversion technique that employs an optical IQ modulator and a dual-polarization quadrature-phase-shift-keying (DP-QPSK) modulator is applicable to binary PSK, QPSK, and 16-ary quadrature(More)
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