Masayuki Izutsu

Optoelectronic frequency response measurement of photodiodes by using high-extinction ratio optical modulator

We propose a measurement method of photodetector frequency response. This technique is based on a heterodyne principle, where a high-extinction ratio Mach-Zehnder modulator is used to generate a two-tone lightwave as a stimulus signal up to millimeter-wave frequency bands. Our proposing method can provide a relatively short traceability chain to optical and electric power standards.

Simple, low fluctuation voltage signal generation for 8-Gb/s quadrature amplitude modulation using dual-parallel Mach-Zehnder modulator

Optical quadrature amplitude modulation (QAM) has attracted considerable attention because of its high spectral efficiency. For high capacity, the modulation rate should also be enhanced, which requires the generation of high-baud-rate multilevel electric signals with high precision in amplitude. In this paper, we describe a method to reduce the amplitude fluctuation of the electric signal by adopting a return-to-zero (RZ) format. We also demonstrate 2.0-Gbaud optical QAM signal generation with a conventional dual-parallel MachZehnder modulator (DPMZM) driven by the electric RZ data signals.

Beam steering array antenna controlled by optical wavelength

We developed a beam forming network (BFN) for an array antenna with 5 elements radiating 3 independently steerable beams, and measured the phase shift characteristics. The main part of the BFN is integrated as a single photonic integrated circuit (PIC) chip using birefringent Lithium Niobate (LN) waveguide. The phase distribution among the 5 element antennas is controlled by the wavelength tuning of an optical RF source. Highly linear phase shift characteristics with the sensitivity of 8.24°/nm are achieved. By using 3 tunable optical RF sources allocated to different wavelength range, the PIC chip can generate feeding signals for 3 independently steerable beams.

Multi-channel RoF signal generation using a reciprocating optical modulator

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.

Analysis of crosstalk impact on optical packet signals in an optical cross-bar switch by intensity-trimming method

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.

Highly pure 160-GHz two-tone lightwave generation using high extinction-ratio optical intensity modulator and delay interferometer

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.

MWP and terahertz technology

The importance will be emphasized to involve terahertz spectrum in the microwave photonic technologies of the next stage.

Frequency swapping using an optical switch with embedded Mach-Zehnder structures for wavelength-converted optical signal routing without lightsources

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.