Readout-signal amplification by homodyne detection scheme

Mikami, Hideharu; Shimano, Takeshi; Kudo, Hiromi; Hashizume, Jiro; Miyamoto, Hiroyuki

doi:10.1117/12.738418

Cited by 11 publications

(10 citation statements)

References 4 publications

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“…An 8T monotone signal level and levels of noise components such as laser noise (including shot noise), disk noise, and amplifier noise were measured using a single-layer BD and applying conventional detection, and their levels for several numbers of layers or the case of applying phase-diversity homodyne detection were estimated by combining the measured and theoretical values shown in ref. 10. The estimated SNR improvement for an eight-layer disk was +7.9 dB, and the SNR became the same order as that of conventional detection with a singlelayer disk.…”

Section: Resultsmentioning

confidence: 64%

Amplification of Optical Disk Readout Signals by Homodyne Detection

Mikami

Shimano

Kurokawa

et al. 2009

jjap

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We experimentally demonstrated the amplification of optical disk readout signals by homodyne detection. This technique uses optical interference to amplify the signals. We further applied phase-diversity detection to reliably obtain the amplified readout signal. The optical system was carefully designed so that a sufficiently amplified readout signal can be obtained. In particular, we applied a corner cube prism as a reflection mirror to achieve sufficient stability of the interferometric optical system. We experimentally demonstrated a 3.6 times amplification of a Blu-ray Disc readout signal. The estimated signal-to-noise ratio (SNR) improvement for an assumed eight-layer optical disk readout signals by applying homodyne detection on the basis of the observed amplification was +7.9 dB, which significantly enables reliable readout of recorded signals. The present technique will be essential for the real commercialization of next-generation multilayer optical disk because of its outstanding ability of SNR improvement.

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Section: Resultsmentioning

confidence: 64%

Amplification of Optical Disk Readout Signals by Homodyne Detection

Mikami

Shimano

Kurokawa

et al. 2009

jjap

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“…(11)] that the optical spot quality decreases linearly with the product of number of layers times the signal strength. An extension of these results to homodyne detection [31,32] would be straightforward. Such scalings, even though derived via a number of approximations, provide a valuable method to evaluate and optimize next-generation optical storage methods.…”

Section: Discussionmentioning

confidence: 87%

“…In the case of fluorescence the return signal is incoherent, whereas in the case of a modified index or absorption it is coherent. In the later case, homodyne detection [31,32] can be used to increase the weak signal strength, but it also amplifies the impact of intertrack and interlayer crosstalk. Virtually all proposed methods employ confocal filtering [19,33] or other depth sectioning methods [34] borrowed from microscopy to suppress interlayer crosstalk between tightly spaced layers.…”

Section: Background and Motivationmentioning

confidence: 99%

Impact of phase aberrations caused by multilayer optical data storage in weakly inhomogeneous media

McLeod

2009

J. Opt. Soc. Am. B

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Various multilayer optical data storage methods have been proposed in which bits are written in an initially homogeneous material. To varying degrees, all of these methods will be constrained by phase aberrations that decrease the Strehl ratio as the number of layers and index perturbation of each bit are increased. Although the exact problem is theoretically and numerically intractable, statistical derivations of the impact are possible. These analytic expressions are derived and validated with simulations of low-capacity disks, and then are used to establish limits in the interesting high-capacity case. The resulting approximate expressions are shown to be remarkably simple and also potentially serious in limiting multilayer data storage capacities.

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“…In this case, the amplification factor of the signal amplitude was 2.3. In this experiment, phase-diversity detection was applied to maintain signal level stability [9]. Throughout this study, the following conditions were applied in the experiments: disc: single-layer BD; readout power: 0.33 mW (at disc surface); readout speed: 1x (CLV 4.917 m/s); power ratio between signal and reference lights (at emission): 1:7.…”

Section: Modification Of Optical Systemmentioning

confidence: 99%

“…In addition, a higher readout speed causes a further decrease in the SNR because a wider bandwidth is required [8]. Therefore, we have been developing an optical system where homodyne detection is applied to overcome the low SNR problem [9][10][11]. Homodyne detection is a signal amplification technique which has been developed in the fields of optics such as optical fiber communication [12].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of readout-signal quality improvement by homodyne detection

et al. 2009

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We experimentally demonstrated improvement in optical disc readout signal quality by homodyne detection. We introduced an optical phase servo system as an alternative to the phase-diversity detection scheme for stabilization of the interference signal in homodyne detection, which resulted in further enhancement of readout signal quality. Experimental results indicate that at least a 16-layer recordable disc can be reliably read out with a jitter of less than 8% at a 1-mW read power by homodyne detection. The estimated amplification of signal amplitude was 13 times.

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Readout-signal amplification by homodyne detection scheme

Cited by 11 publications

References 4 publications

Amplification of Optical Disk Readout Signals by Homodyne Detection

Amplification of Optical Disk Readout Signals by Homodyne Detection

Impact of phase aberrations caused by multilayer optical data storage in weakly inhomogeneous media

Demonstration of readout-signal quality improvement by homodyne detection

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