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en: All-photonic W-band terahertz receiver based on THz-to-optical carrier conversion with soliton microcomb dual carriers for high-speed OOK wireless transmission

en: We demonstrate an all-photonic terahertz (THz) receiver for a data-modulated signal, targeting a 106-GHz, 2.97-Gb/s on-off keying (OOK) link. The scheme employs dual-wavelength optical carriers referenced to a soliton microcomb and performs THz-to-optical carrier conversion via nonpolarimetric electro-optic downconversion using an electro-optic polymer modulator. RF spectra and eye diagrams confirmed error-free transmission with a Q-factor of 5.78 and a bit-error rate of 3.74×109, well below the hard-decision forward-error-correction threshold (Q-factor=2.67, (BER) = 3.8×103). Comparative measurements using a single-wavelength optical-carrier configuration clearly revealed the superior signal-to-noise performance of the dual-wavelength scheme. System-level modeling further indicated the scalability of the transmission distance beyond 100m. These results establish soliton microcomb-referenced dual carriers as a promising platform for compact, integrated receivers enabling seamless wireless-optical convergence in future 6G networks.

en: Optics Express

ja: Optics Express


en: Optimizing 20 Gbps of ground-to-satellite free-space optical communication in low earth orbit with hybrid wavelength-mode division multiplexing

en: Physica Scripta

ja: Physica Scripta


en: A Simple Beam Expanded for Indoor Optical Wireless Communication with Short Transmission Distance

en: Optics Communications

ja: Optics Communications


en: Multi-point temperature sensing using a linear-cavity lasing system

en: A multi-point fiber sensing system formed from a linear cavity laser is proposed. Various optical sensing systems have been investigated, for example, using fiber Bragg grating (FBG) and Brillouin scattering for multi-point sensing. This paper focuses on a simple sensing system by using multi-wavelength lasing with parallel cavities and a semiconductor optical amplifier (SOA). First, optical nonlinearity in amplification of the SOA is discussed to clarify the effects of gain saturation and four-wave mixing on the proposed multi-channel sensing system. And then lasing conditions in the linear cavity laser consisting of an SOA, an arrayed waveguide grating (AWG), and FBGs are theoretically investigated. The multi-wavelength lasing power is found to be limited mainly by gain saturation in the SOA. The lasing power for the eight-channel system is evaluated to be -8.5 dBm when the total loss in the linear cavity is 10 dB. The lasing power can be increased by 3 dB when the channel number is decreased to four. Next, multi-wavelength lasing in the cavity consisting of an SOA, an AWG, a loop mirror, and fiber mirror reflectors is experimentally demonstrated up to eight channels. Finally, two-channel temperature sensing ranging from 13°C to 76°C is experimentally confirmed by using two FBGs as the sensing elements with an AWG having 100-GHz bandwidth.

en: Applied Optics

ja: Applied Optics


en: Optical Label Routing Processing for BPSK Labels Using Complex-Valued Neural Network

en: IEEE/OSA Journal of Lightwave Technology


en: Designing of Optical Switch Controlled by Light Intensity in Cascaded Optical Couplers

en: Optical Engineering

ja: Optical Engineering


en: Optical Switch by Light Intensity Control in Cascaded Coupled Waveguides

en: Lightwave switching is discussed with a cascaded connection of optical couplers with light intensity control elements. By employing wavelength-selective amplifiers such as a waveguide-type Raman amplifier, all-optical wavelength-selective switching can be realized. We discuss analytically using coupled-mode theory that the lightwave switching is feasible by controlling the intensity of propagating lightwave. The switching operation is verified numerically using finite-difference beam-propagation method. As a result, the expected operation is realized and some characteristics involved with dependencies of wavelength and phase are also investigated. A preliminary experiment using attenuators, beam splitters and mirrors is also described to verify the switching operation with only light-intensity control in interferometers.

en: IEICE Transactions on Electronics

ja: IEICE Transactions on Electronics


en: Simultaneously two-parameter measurement using tilted fiber grating and long period fiber grating

en: Microwave and Optical Technology Letters