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About 10,000 papers for “Phase modulation”

Phase Modulation — Frequency Modulation

Bruno Korst · 2016

This experiment includes the simulation and implementation of both FM modulator and demodulator. The particular case of a sinusoidal message signal modulating a sinusoidal carrier will be studied in detail. At the end of the experiment, students are encouraged to pair with neighbouring groups to implement a full modulation-demodulation system, using music from an mp3 player/phone and listening to the demodulated signal with

Cited by 0

Phase-modulation scatterometry

C. Logofatu · Applied Optics · 2002

Phase-modulation scatterometry is a metrology technique for determining, by means of a phase modulator as a key device, the parameters of gratings. The main source of error to be dealt with are the fluctuations of the phase-modulation amplitude. The grating zeroth-order reflectance modulated by the phase modulator is converted into a signal by the photodetector. The measurables are the direct term and the first two harmonics of the signal. For experimental data fitting, we used the ratio of the harmonics over the direct term because it significantly improves the accuracy. A sensitivity analysis was performed for two samples, one real and one theoretical, to find the measurement configuration that insures optimum determination precision for the grating parameters. For the real sample, comparison of the theoretical predictions for sensitivity with the actual values showed a good agreement. For both samples the sensitivity analysis indicated subnanometric precision for the critical dimension (grating linewidth).

Cited by 14

Digital Phase Modulation

Aulin, Tor, Anderson, John, Sundberg, Carl-Erik · Chalmers Publication Library (Chalmers University of Technology) · 1986

Cited by 3

Photoelastic modulator: polarization modulation and phase modulation

Dong Yang, J. C. Canit, E Gaignebet · Journal of optics · 1995

Photoelastic modulators are studied here as both birefringence (or polarization) and phase modulators. In the first part of this work we have determined the influences of time dependent variations of index and thickness, for an ideal modulator where oscillation is supposed to be perfectly longitudinal. An interferometric experiment allowed the validation of the results obtained. In the second part, we have calculated the exact modes of oscillation of the modulator by means of a software based on the method of finite elements. We have determined in this way the homogeneity of stresses and deformations in the modulator and the distribution of indices and birefringences. This allowed us to define the limits of validity of the generally used ideal model, previously studied.

Cited by 18

Carrierless Amplitude Phase Modulation

Tim Collins · 2007

This chapter contains sections titled: Introduction Fundamentals of Amplitude Phase Modulation Implementation Timing and Synchronization Multidimensional Carrierless Amplitude Phase Modulation Conclusion Glossary Cross References References

Cited by 2

Deep phase modulation interferometry

Gerhard Heinzel, Felipe Guzmán Cervantes, A F García Marín et al. · Optics Express · 2010

We have developed a method to equip homodyne interferometers with the capability to operate with constant high sensitivity over many fringes for continuous real-time tracking. The method can be considered as an extension of the "J1 . . .J4" methods, and its enhancement to deliver very sensitive angular measurements through Differential Wavefront Sensing is straightforward. Beam generation requires a sinusoidal phase modulation of several radians in one interferometer arm. On a stable optical bench, we have demonstrated a long-term sensitivity over thousands of seconds of 0.1 mrad/√Hz that correspond to 20 pm/ √Hz in length, and 10 nrad/ √Hz in angle at millihertz frequencies.

Cited by 54Open access

Cross-phase modulation imaging

Prathyush Samineni, Baolei Li, Jesse W. Wilson et al. · Optics Letters · 2012

We demonstrate a cross-phase modulation measurement technique based on the sensitive detection of modulation transfer in a pump-probe setup. By modulating the amplitude of the pump beam and spectrally analyzing the probe beam, we achieve a rapid, background-free measurement of nonlinear phase modulation using power levels acceptable in biological imaging. This measurement technique would allow the extension of widely employed phase microscopy methods to the nonlinear regime, providing intrinsic and universal nonlinear contrast for biological imaging.

Cited by 22

Ultrafast atomic phase modulation

Uvo Holscher, Stephen D. Clow, Thomas Weinacht · Physical Review A · 2009

We demonstrate a phenomenon very similar to electromagnetically induced transparency using a shaped ultrafast laser pulse. Pulse shaping allows us to produce probe and coupling pulses with arbitrary intensities and time delays. The coupling Rabi frequency and probe bandwidth are both on the order of 1 THz, which is much larger than the natural or Doppler broadened linewidth of the probe transition. Important dynamics associated with a time-dependent coupling field are discussed.

Cited by 3

Optical Phase-Modulation Techniques

P√©rez Men√©ndez, Ram√≥n Jos√© · BiblioBoard Library Catalog (Open Research Library) · 2019

Optical phase-modulation technique is a very powerful tool used in a wide variety of high performance photonic systems. Fiber-optic sensors and gyroscopes, integrated-optics sensors, or high-performance photonic integrated circuits are some examples of photonic systems where the optical phase-modulation technique can be efficiently applied. In time, such a photonic system can be integrated as the core part of some specific applications like biosensors, 5G advanced optical communication devices, gyroscopes, or high-performance computation devices. In this work, the main optical phase-modulation techniques are analyzed. Also, a study of the most significant applications of this technique is made, relating it to the most appropriate type in each case.

Cited by 0Open access