40 Gbit/s versatile LiNbO

Kawanishi, Tetsuya; Higuma, Kaoru; Fujita, Takahisa; Mori, Satoshi; Oikawa, Satoshi; Ichikawa, Junichiro; Sakamoto, Takahide; Izutsu, Masayuki

doi:10.1049/cp:20050754

Cited by 19 publications

(14 citation statements)

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“…For high-extinction ratio optical modulation, we used an integrated MZ modulator designed for high-speed frequency-shift-keying [4], where the main MZ has a dual-electrode structure. The halfwave voltage for push-pull operation was 2.5V at dc.…”

Section: Resultsmentioning

confidence: 99%

“…However, the modulation frequency is limited by the frequency response of the modulator. A typical 3dB bandwidth of a modulator is 30 GHz [4], so that the frequency upper limit of the two-tone signal generated by DSB-SC modulation can not be larger than 100 GHz. Recently, a novel optical modulation scheme for highfrequency millimetre wave generation was reported, where 76GHz millimetre wave generation from 19GHz was demonstrated [5].…”

Section: Introductionmentioning

confidence: 99%

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160GHz two-tone lightwave generation using high extinction-ratio optical modulation

Kawanishi¹,

Sakamoto²,

Tsuchiya³

et al. 2006

2006 IEEE LEOS Annual Meeting Conference Proceedings

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By using a high extinction-ratio optical Mach-Zehnder modulator biased at a maximum transmission point, we demonstrated generation of a two-tone lighwave consisting of the second order sideband components whose frequency separation was 160GHz. IntroductionTwo-tone lightwave signal generation has played important roles in radio-on-fibre links, radio astronomy, etc [1,2,3], where the two-tone lightwave consists of two phase-locked spectral components. A pair of laser sources with an optical phase-locked loop (OPLL) for feedback control can generate a two-tone lightwave, however, it is not easy to obtain stable operation of OPLL. On the other hand, LiNbO3 MachZehnder (MZ) optical intensity modulators can generate stable upper sideband (USB) and lower sideband (LSB) components, by feeding sinusoidal rf signals. The output spectrum depends on the dc bias voltage applied on the electrode in the MZ structure. When the bias is set to a minimum transmission point, double-sideband suppressed carrier (DSB-SC) optical modulation can be achieved, where the output has the first order LSB and USB. The frequency separation between the two spectral components is precisely equal to double the modulating signal frequency [1]. The spectral components generated by optical modulation are always phase-locked, so that we can easily construct robust systems without using complicated feedback control techniques. However, the modulation frequency is limited by the frequency response of the modulator. A typical 3dB bandwidth of a modulator is 30 GHz [4], so that the frequency upper limit of the two-tone signal generated by DSB-SC modulation can not be larger than 100 GHz. Recently, a novel optical modulation scheme for highfrequency millimetre wave generation was reported, where 76GHz millimetre wave generation from 19GHz was demonstrated [5]. A MZ modulator whose bias was set to a maximum transmission point was used to generate the second order LSB and USB, where the output also contained the input carrier frequency component. A high-frequency two-tone signal of the fourth order harmonic of the signal fed to the modulator can be generated by filtering out the carrier component. The first sideband components are suppressed in the modulator, however, the suppression ratio depends on the extinction ratio of the MZ modulator. Some additional filters are needed to obtain high suppression ratio. However, the optical frequencies of the first order sidebands vary with the modulation frequency, so that we need high performance tuneable optical filters to obtain the

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

160GHz two-tone lightwave generation using high extinction-ratio optical modulation

Kawanishi¹,

Sakamoto²,

Tsuchiya³

et al. 2006

2006 IEEE LEOS Annual Meeting Conference Proceedings

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“…Recently, we reported an integrated modulator based on a high-speed FSK modulator, where the modulator has six traveling wave electrodes and a pair of sub Mach-Zehnder interferometers (MZIs) embedded in a main MZI [7]. This modulator is called a versatile lightwave modulator, because it can generate various types of lightwave signals, such as, return-to-zero (RZ) OOK, DQPSK, wideband FSK, continuousphase FSK [9], etc.…”

Section: High-speed Dqpsk Modulation Using Integrated Modulatormentioning

confidence: 99%

“…1, the versatile modulator consists of two sub MZ structures (MZA and MZB), with six optical phase modulators. For DQPSK modulation, two data signals are applied to the two sub MZIs, to achieve control of in-phase and quadrature components [7], as shown in Fig. 2.…”

Section: High-speed Dqpsk Modulation Using Integrated Modulatormentioning

confidence: 99%

Optical Modulators for 100 GbE

Kawanishi

2007

LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings

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“…In particular, DQPSK modulation method has drawn most attention for the 40 Gbps optical communication system because it is expected to be better-tolerated to polarization mode dispersion. A nested Mach-Zehnder (MZ) modulator, previously reported as an integrated LiNbO 3 (LN) versatile optical modulator consisting of two sub MZ interferometers with signal electrodes embedded in a main MZ interferometer [4], can generate optical signals in various modulation formats. This modulator can control the in-phase (I) and quadrature (Q) components of the output lightwave in each sub MZ interferometer, and is applicable for DQPSK modulation.…”

Section: Introductionmentioning

confidence: 99%

A bias condition monitor technique for the nested Mach-Zehnder modulator

Higuma

Mori

Kawanishi

et al. 2006

IEICE Electron. Express

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Abstract:A nested Mach-Zehnder (MZ) modulator, which consists of two sub MZ interferometers embedded in a main MZ interferometer, is a multifunctional modulator. It can work as an optical single side-band (SSB) modulator, a differential quadrature phase shift keying (DQPSK) modulator and so on. Despite difficulties due to their complex structure, in order to avoid the operation instability of such modulators the bias condition of each MZ interferometer must be controlled automatically according to the modulation formats. In this paper, we proposed a specific bias condition monitor technique to the nested modulator.

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40 Gbit/s versatile LiNbO

Cited by 19 publications

References 0 publications

160GHz two-tone lightwave generation using high extinction-ratio optical modulation

160GHz two-tone lightwave generation using high extinction-ratio optical modulation

Optical Modulators for 100 GbE

A bias condition monitor technique for the nested Mach-Zehnder modulator

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