An electrooptic intensity modulator with improved linearity

Farwell, Mark; Lin, Zong Qi; Wooten, E.L.; Chang, William S. C.

doi:10.1109/68.84495

Cited by 69 publications

(15 citation statements)

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“…This is shown in Fig. 2 where we plot the calculated SFDR as a function of the total RF loss across the electrode for four different linearized DCMs: the Y-fed two-section DCM; two other variations of multisectioned linearized DCMs; a three-section DCM that consists of a 2 2 DCM followed by two DCM bias sections to which only a dc bias is applied [1], and a two-section DCM which consists of a Y-fed DCM followed by one dc bias section; the 1 2 DCM with . The results shown in Figs.…”

Section: Resultsmentioning

confidence: 99%

“…Modifications to the basic DCM architecture, such as inclusion of additional bias structures can, in principle, improve the two-tone SFDR to over 130 dB Hz . Numerous variations of the modified DCM have been proposed [1]- [5]. Modeling of some of these linearized architectures showed that although the gain could have a broad frequency response, the SFDR bandwidth was limited by velocity mismatch [6], [7].…”

Section: Introductionmentioning

confidence: 99%

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Effect of electrode loss on the dynamic range of linearized directional coupler modulators

Brost

Michalak

Payson

et al. 2006

IEEE Photon. Technol. Lett.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of electrode loss on the dynamic range of linearized directional coupler modulators

Brost

Michalak

Payson

et al. 2006

IEEE Photon. Technol. Lett.

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“…Let be the transfer function, where is the normalized modulator drive voltage and is the active length of the modulator. If the optical and electrical waves travel at the same velocity, or if the operating frequency is so low that is effectively constant over , then the output is given by (5) Even if there is significant velocity dispersion while the two waves travel the distance , over a short enough section of the guide , the change in the complex optical amplitudes may be described with the dc transfer function. This is the basis for the frequency dependent calculation.…”

Section: A Computation Of Modulators With Velocity Dispersionmentioning

confidence: 99%

Bandwidth of linearized electrooptic modulators

Cummings

Bridges

1998

J. Lightwave Technol.

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Abstract-Many schemes have been proposed to make high dynamic range analog radio frequency (RF) photonic links by linearizing the transfer function of the link's modulator. This paper studies the degrading effects of finite transit time and optical and electrical velocity dispersion on such linearization schemes. It further demonstrates that much of the lost dynamic range in some modulators may be regained by segmenting and rephasing the RF transmission line.

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“…Given the critical bias conditions and the fact that the distortion cancellation sections are in series, unlike the DPMZM, the rapid degradation with dynamic range is reasonable. The original experiments on this modulator were performed at audio frequencies where these effects would not be noticed [5]. Subsequently, measurements at 1 and 2 GHz [6] were singlefrequency measurements, with the bias values reoptimized for the operating frequency; no bandwidth measurements around 1 and 2 GHz were made.…”

Section: Broad-band Linearized Modulatorsmentioning

confidence: 99%

“…Dynamic range values are calculated for two linearized broad-band, or superoctave, modulators: the dual parallel Mach-Zehnder (DPMZM) and the directional coupler with two passive sections (DCM2P) which are described in [4] and [5], respectively. The DPMZM has two identical, single Mach-Zehnder modulators in parallel optically and electrically but with unequal levels of optical and RF power driving the two modulators.…”

Section: Broad-band Linearized Modulatorsmentioning

confidence: 99%

Wave-Coupled Millimeter-Wave Electro-Optic Techniques

Bridges¹,

Burrows²,

Cummings³

2001

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AGENCY USE ONLY (Leaveblank)2. REPORT DATE MARCH 2001 REPORT TYPE AND DATES COVEREDFinal Report Feb 96 -Jun 00 TITLE AND SUBTITLE WAVE-COUPLED MILLIMETER-WAVE ELECTRO-OPTIC TECHNIQUES AUTHOR(S)William B. Bridges, Lee J. Burrows, and Uri V. Cummings FUNDING NUMBERSC -F30602-96-C-O020 PE-63726F PR-2863 TA-92 WU-81 PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)California Institute of Technology Office of Sponsored Programs 1201 East California Blvd, MC 213-6 Pasadena CA 91125 PERFORMING ORGANIZATION REPORT NUMBERN/A SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air 12b. DISTRIBUTION CODE ABSTRACT (Maximum 200 words)This report details results on two antenna-coupled millimeter-wave electro-optic modulators, the slot-vee antenna-coupled modulator and a 94 GHz directional coupler modulator. The slot-vee-coupled modulator gave 0.17 m-squared per Watt sensitivity, but known defects in the chip imply much better performance is possible. The 94 GHz directional coupler improvements anticipated were not realized due to fabrication problems. A detailed theoretical study of the effects of velocity mismatch on linearized electr-optic modulators was made and the results published. A key result was that directional-coupler based modulators were found to be significantly more easily degraded than some Mach-Zehnder-based modulators. An experimental study of bias drift in electro-optic modulators was made and protons were determined to be the cause. Several inventions were made to reduce or eliminate proton-caused bias drift. Gain of Y-fed DCM below 6 = 1.5 n 42 SUBJECT TERMSComparison of vee and slot-vee antennas on a dielectric substrate 46Schematic drawing of slot-vee antenna elements overlaying one waveguide of a Mach-Zehnder modulator 48Schematic view of the slot-vee modulator 49Schematic drawing of the slot-vee modulator and its microwave feed system 50Antenna mask for 5 slot-vee modulators 51Assembly drawing of modulator support and feed structure 54Photograph of slot-vee modulator test setup with fiber-input coupling and lens output coupling 55 in List Of Tables Table 6.1 Comparison of Experimental and Theoretical Diffusion Depths 78 IV EXECUTIVE SUMMARYThis report documents the progress made in improving antenna-coupled modulators for mmwave, analyzing linearized modulators, and studying and countering bias drift in electro-optic modulators.We demonstrated for the first time a modulator at 24 GHz using the slot-vee antenna coupled arrangement suggested by F. T. Sheehy in a previous Rome Laboratory contract. The actual performance was measured as 0.17 m 2 /Watt, comparable to other antenna coupled modulators we have built. However, known defects in this particular chip suggest that future performance would be much better, comparable to commercial low microwave frequency modulators.Our attempts to correct the known defects in the 94 GHz directional coupler modulator first demonstrated in the previous contract were unsuccessful, due to difficulties in developing the skills needed to transfer the fabrication tec...

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An electrooptic intensity modulator with improved linearity

Cited by 69 publications

References 4 publications

Effect of electrode loss on the dynamic range of linearized directional coupler modulators

Effect of electrode loss on the dynamic range of linearized directional coupler modulators

Bandwidth of linearized electrooptic modulators

Wave-Coupled Millimeter-Wave Electro-Optic Techniques

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