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Hiroshi MURATA
2015 年 E98.C 巻 8 号 p.
751
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
フリー
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Lawrence R. CHEN
原稿種別: INVITED PAPER
2015 年 E98.C 巻 8 号 p.
752-763
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
フリー
We provide an overview of techniques for the photonic generation of arbitrary RF waveforms, particularly those suitable for impulse radio or multi-band ultrawideband (UWB)-over-fiber transmission, and chirped microwave waveforms, with an emphasis on microwave photonic filtering and optical spectral shaping followed by wavelength-to-time mapping. We discuss possibilities for integrating the various device and component technologies with silicon photonics.
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Andreas BELING, Joe C. CAMPBELL, Kejia LI, Qinglong LI, Ye WANG, Madis ...
原稿種別: INVITED PAPER
2015 年 E98.C 巻 8 号 p.
764-768
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
フリー
This paper summarizes recent progress on modified uni-traveling carrier photodiodes that have achieved RF output power levels of 1.8 Watt and 4.4 Watt in continuous wave and pulsed operation, respectively. Flip-chip bonded discrete photodiodes, narrowband photodiodes, and photodiodes integrated with antennas are described.
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Katsuyuki YAMAMOTO, Tadashi KAWAI, Akira ENOKIHARA, Tetsuya KAWANISHI
原稿種別: PAPER
専門分野: MWP Device and Application
2015 年 E98.C 巻 8 号 p.
769-776
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
Optical single sideband (SSB) modulation with the Mach-Zehnder (MZ) interferometer was realized by integrating the modulation electrode with the branch-line coupler (BLC) as a 90-degree hybrid onto the modulator substrate. In this paper, BLCs of the microsrtip-line structure were miniaturized on modulator substrates, LiNbO
3 (LN), to realize more compact optical SSB modulators. We introduced two techniques of miniaturizing the BLC, one is using periodically installed open-circuited stabs and the other is installing series capacitors. Compared with a conventional pattern of the BLC, an area of the miniaturized BLC by using periodically installed open-circuited stubs was reduced to about 50%, and that by installing series capacitors was done to about 60%. The operation of these miniaturized BLCs was experimentally confirmed as the 90-degree hybrid at around 10GHz. Output ports of each miniaturized BLC were directly connected with the modulation electrode on the modulator substrate. Thereby, we fabricated two types of compact SSB modulators for 1550nm light wavelength. In the experiments, the optical SSB modulation was successfully confirmed by the output light spectra and the sideband suppression ratio of more than 30dB were observed.
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Akira ENOKIHARA, Masashi YAMAMOTO, Tadashi KAWAI, Tetsuya KAWANISHI
原稿種別: PAPER
専門分野: MWP Device and Application
2015 年 E98.C 巻 8 号 p.
777-782
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
An electro-optic (EO) modulator integrated with the microwave planar circuit directly formed on a LiNbO
3 (LN) substrate for low frequency-chirp performance and compact configuration is introduced. Frequency chirp of EO intensity modulators was investigated and a dual-electrode Mach-Zehnder (MZ) modulator combined with a microwave rat-race (RR) circuit was considered for the low-chirp modulation. The RR circuit, which operates as a 180-degree hybrid, was designed on a
z-cut LN substrate to create two modulation signals of the same amplitude in anti-phase with each other from a single input signal. Output ports of the RR were connected to the modulation electrodes on the substrate. The two signals of the equal amplitude drive two phase modulation parts of the modulator so that the symmetric interference are realized to obtain intensity modulation of low frequency-chirp. The modulator was designed and fabricated on a single LN substrate for around 10 GHz modulation frequencies and 1550 nm light wavelength. The chirp parameters were measured to be less than 0.2 in the frequency range between 8 and 12 GHz. By compensating imbalance of the light power splitting in the waveguide MZ interferometer the chirp could be reduced even more.
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Yusuf Nur WIJAYANTO, Atsushi KANNO, Hiroshi MURATA, Tetsuya KAWANISHI, ...
原稿種別: PAPER
専門分野: MWP Device and Application
2015 年 E98.C 巻 8 号 p.
783-792
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
A millimeter-wave radar receiver using a
z-cut LiNbO
3 optical modulator with orthogonal-gap-embedded patch-antennas on a low-
k dielectric material is proposed. A millimeter-wave from a reflected radar signal can be received by the patch-antennas and converted directly to a lightwave through electro-optic modulation. A low-
k dielectric material is used as a substrate for improving antenna gain. Additionally, an interaction length between millimeter-wave and lightwave electric fields becomes long. As a result, large modulation efficiency can be obtained, which is proportional to sensitivity of the millimeter-wave radar receiver. Optical millimeter-wave radar beam-forming can be obtained using the proposed device with meandering-gaps for controlling interaction between millimeter-wave and lightwave electric fields in electro-optic modulation. Analysis and experimentally demonstration of the proposed device are discussed and reported for 40GHz millimeter-wave bands. Optical millimeter-wave radar beam-forming in 2-D is also discussed.
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Isao MOROHASHI, Takahide SAKAMOTO, Norihiko SEKINE, Tetsuya KAWANISHI, ...
原稿種別: PAPER
専門分野: MWP Subsystem
2015 年 E98.C 巻 8 号 p.
793-798
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
We demonstrated generation of arbitrarily patterned optical pulse trains and frequency tunable terahertz (THz) pulses by spectral synthesis of optical combs generated by a Mach-Zehnder-modulator-based flat comb generator (MZ-FCG). In our approach, THz pulses were generated by photomixing of a multi-tone signal, which is elongated pulse train, and a single-tone signal. Both signals were extracted from a comb signal by using optical tunable bandpass filters. In the case of optical pulse train generation, the MZ-FCG generated comb signals with 10 GHz-spacing and 330 GHz-width, which was converted to a 2.85 ps-width pulse train by chirp compensation using a single-mode fiber. By combining the MZ-FCG with a pulse picker composed of a 40 Gbps intensity modulator, divided pulse trains and arbitrarily bit sequences were successfully generated. The single-mode light was extracted by an optical bandpass filter and the band-controlled pulse train was extracted by an optical bandpass filter. By photomixing them, a THz pulse was successfully generated. In the case of THz pulse generation, by photomixing a single-tone and a multi-tone signals extracted by tunable bandpass filters, THz pulses with a center frequency of 300 GHz was successfully generated. Furthermore, frequency tunability of the center frequency was also demonstrated.
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Shigeru KUWANO, Daisuke IIDA, Jun TERADA, Akihiro OTAKA, Naoto YOSHIMO ...
原稿種別: PAPER
専門分野: MWP Subsystem
2015 年 E98.C 巻 8 号 p.
799-807
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
Terahertz (THz) band is an attractive candidate for future broadband (> 10 Gb/s) wireless backhaul and fronthaul. THz transmitter employing optical frequency comb can provide high quality THz carrier, and is useful to the future broadband THz communication systems based on coherent transmission technique. To realize coherent transmission, high quality carrier generation is essential and it is important to evaluate the signal quality of a THz transmitter. In this paper, we derive error vector magnitude (EVM) including optical impairments (optical amplifier noise, laser phase noise, optical crosstalk and IQ imbalance of optical modulator) of the optical frequency comb based transmitter. The calculated EVM is in good agreement with simulated one, and practical requirements for optical impairment are indicated. The analysis will be useful in the design of THz transmission systems employing an optical frequency comb.
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Tomotaka NAGASHIMA, Makoto HASEGAWA, Takuya MURAKAWA, Tsuyoshi KONISHI
原稿種別: PAPER
専門分野: Optical A/D Conversion
2015 年 E98.C 巻 8 号 p.
808-815
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
We investigate a quantization error improvement technique using a dual rail configuration for optical quantization. Our proposed optical quantization uses intensity-to-wavelength conversion based on soliton self-frequency shift and spectral compression based on self-phase modulation. However, some unfavorable input peak power regions exist due to stagnations of wavelength shift or distortions of spectral compression. These phenomena could induce a serious quantization error and degrade the effective number of bit (ENOB). In this work, we propose a quantization error improvement technique which can make up for the unfavorable input peak power regions. We experimentally verify the quantization error improvement effect by the proposed technique in 6 bit optical quantization. The estimated ENOB is improved from 5.35 bit to 5.66 bit. In addition, we examine the XPM influence between counter-propagating pulses at high sampling rate. Experimental results and numerical simulation show that the XPM influence is negligible under ∼40 GS/s conditions.
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Irneza ISMAIL, Quang NGUYEN-THE, Motoharu MATSUURA, Naoto KISHI
原稿種別: PAPER
専門分野: Advanced Photonics
2015 年 E98.C 巻 8 号 p.
816-823
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
All-optical 1-to-6 wavelength multicasting of a 10-Gb/s picosecond-tunable-width converted return-to-zero (RZ)-on-off-keying (OOK) data signal using a wideband-parametric pulse source from a distributed Raman amplifier (DRA) is experimentally demonstrated. Width-tunable wavelength multicasting within the C-band with approximately 40.6-nm of separation with various compressed RZ data signal inputs have been proposed and demonstrated. The converted multicast pulse widths can be flexibly controlled down to 2.67 ps by tuning the Raman pump powers of the DRA. Nearly equal pulse widths at all multicast wavelengths are obtained. Furthermore, wide open eye patterns and penalties less than 1.2 dB at the 10
-9 bit-error-rate (BER) level are found.
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Quynh NGUYEN QUANG NHU, Quang NGUYEN-THE, Hung NGUYEN TAN, Motoharu MA ...
原稿種別: PAPER
専門分野: Advanced Photonics
2015 年 E98.C 巻 8 号 p.
824-831
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
A combination of nonreturn-to-zero (NRZ)-to-return-to-zero (RZ) waveform conversion and wavelength multicasting with pulsewidth tunability is experimentally demonstrated. A NRZ data signal is injected into a highly nonlinear fiber (HNLF)-based four-wave mixing (FWM) switch with four RZ clocks compressed by a Raman amplification-based multiwavelength pulse compressor (RA-MPC). The NRZ signal is multicast and converted to RZ signals in a continuously wide pulsewidth tuning range between around 12.17 and 4.68 ps by changing the Raman pump power of the RA-MPC. Error-free operations of the converted RZ signals with different pulsewidths are achieved with negative power penalties compared with the back-to-back NRZ signal and the small variation among received powers of RZ output channels at a bit-error-rate (BER) of 10
-9. The NRZ-to-RZ waveform conversion and wavelength multicasting without using the RA-MPC are also successfully implemented.
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Masaki SHIRAIWA, Yoshinari AWAJI, Naoya WADA, Atsushi KANNO, Toshiaki ...
原稿種別: PAPER
専門分野: RoF and Applications
2015 年 E98.C 巻 8 号 p.
832-839
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
We report the adaptability of the burst-mode erbium-doped fiber amplifier (BM-EDFA) for uplink transmission of sharply rising analog radio-over-fiber (RoF) signals by using long-term evolution (LTE) -Advanced format on a mobile front-haul. Recent drastically increased mobile data traffic is boosting the demand for high-speed radio communication technologies for next-generation mobile services to enhance user experience. However, the latency become increasingly visible as serious issues. Analog RoF technology is a promising candidate for a next generation mobile front-haul to realize low latency. For the uplink, an RoF signal may rise sharply in response to a burst of in-coming radio signals. We propose that a newly developed BM-EDFA is applied for such a sharply rising RoF signal transmission. The BM-EDFA that we designed using enhanced intrinsic saturation power EDF to suppress the gain transient caused by received optical power fluctuations with optical feedback. The new BM-EDFA was designed for a wider linear output power range and lower NF than the previous BM-EDFA. The observed range of received optical power satisfying an error vector magnitude of less than 8%rms achieved over 16dB. We consider that our BM-EDFAs with wide linear ranges of output power will be a key device for the LTE-Advanced RoF uplink signal transmission via optical access networks for the next-generation mobile front-haul.
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Pham TIEN DAT, Atsushi KANNO, Tetsuya KAWANISHI
原稿種別: PAPER
専門分野: RoF and Applications
2015 年 E98.C 巻 8 号 p.
840-848
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
In this paper, we propose a flexible and high-capacity front-haul link for the uplink transmission of high-speed mobile signals using a cascade of radio-on-radio (RoR) and radio-over-fiber (RoF) systems. To emulate the cases that may occur in the uplink direction, we experimentally investigate the performance of superposing an uplink bursty LTE-A signal on the cascaded system using optical packet signal transmission. The performance of systems using different types of erbium-doped fiber amplifiers (EDFAs), including a high-transient EDFA, an automatic-gain-control EDFA, and a burst-mode (BM) EDFA is evaluated and compared. We confirm that the dynamic transience of the EDFAs has a significant influence on the signal performance. By using a BM-EDFA, we confirm successful transmission of the uplink packetized LTE-A signal on the cascaded system. Both the measured error vector magnitude and the received optical power range metrics exceed the requirements. We also estimate the maximum transmission range of the RoR link, and it is confirmed that a sufficiently long range could be achieved for the applications in mobile front-haul networks.
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Toshiaki KURI, Atsushi KANNO, Tetsuya KAWANISHI
原稿種別: PAPER
専門分野: MWP Sensing Technique
2015 年 E98.C 巻 8 号 p.
849-856
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
A re-configurable wavelength de-multiplexer for wave-length-division-multiplexed (WDM) radio-over-fiber (RoF) systems, which is specially designed for delivering frequency-modulated continuous-wave (FM-CW) signals, is newly developed. The principle and characteristics of the developed de-multiplexer are described in detail. Then the de-multiplexing performances of 4-channel WDM 32-GHz-band, 8-channel WDM 48-GHz-band, and 5-channel WDM 96-GHz-band FM-CW RoF signals are evaluated with the de-multiplexer.
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Benoît J. GOUHIER, Ka-Lun LEE, Ampalavanapillai NIRMALATHAS, Christina ...
原稿種別: PAPER
専門分野: MWP Sensing Technique
2015 年 E98.C 巻 8 号 p.
857-865
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
In this paper, we present a new electro-optic (EO) probing system based on heterodyne detection. The use of a recirculating frequency shifter allows to expand the bandwidth of the system far beyond what is attainable with a conventional heterodyne EO set-up. The performance for the frequencies up to 50GHz is analysed to forecast the viability of the system up to the THz range.
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Hai Huy NGUYEN PHAM, Shintaro HISATAKE, Tadao NAGATSUMA
原稿種別: PAPER
専門分野: MWP Sensing Technique
2015 年 E98.C 巻 8 号 p.
866-872
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
We demonstrate the characterization of a horn antenna in the full F-band (90 ∼ 140 GHz) based on far-field transformation from near-field electro-optic (EO) measurement. Our nonpolarimetric self-heterodyne EO sensing system enables us to simultaneously measure the spatial distribution of the amplitude and phase of the RF signal. Because free-running lasers are used to generate and detect the RF signal, our EO sensing system has wide frequency tunability. Owing to the stable and reliable amplitude and phase measurements with minimal field perturbation, the estimated far-field patterns agree well with those of the simulated results. We have evaluated the estimation errors of the 3-dB beamwidth and position of the first sidelobe. The largest standard error of the measurements was 1.1
° for 3-dB beamwidth and 3.5° for the position of first sidelobe at frequency 90 GHz. Our EO sensing system can be used to characterize and evaluate terahertz antennas for indoor communication applications such as small-size slot array antennas.
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Hiroshi YAMAMOTO, Hiroshi ITO
原稿種別: PAPER
専門分野: MWP Sensing Technique
2015 年 E98.C 巻 8 号 p.
873-877
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
The use of an interface-planarization (IP) prism in millimeter-wave ellipsometry is proposed to achieve reproducible measurements of soft, protean, and non-flat samples. The complex relative dielectric constants of a slice of bovine tissue were successfully measured at frequencies from 90 to 140 GHz using the IP prism to confirm its applicability. The use of the IP prism was found to be advantageous for protecting the sample surface from the desiccation during the measurements.
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Naokatsu YAMAMOTO, Kouichi AKAHANE, Toshimasa UMEZAWA, Tetsuya KAWANIS ...
原稿種別: BRIEF PAPER
専門分野: MWP Device and Application
2015 年 E98.C 巻 8 号 p.
878-881
発行日: 2015/08/01
公開日: 2015/08/01
ジャーナル
認証あり
A quantum dot (QD) electro-absorption device was successfully developed with a highly stacked InAs/InGaAlAs QD structure. A 1.55-µm waveband electro-absorption effect and a quantum confined Stark effect of approximately 22 meV under the application of a 214-kV/cm reverse bias electric field are clearly observed in the developed QD device.
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