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Influences of variable-angle polarization-rotated optical feedback on polarization properties of vertical-cavity surface-emitting lasers (VCSELs) are investigated numerically. For the so-called case A (x polarization) feedback, only the x mode is selected to pass through the feedback loop. As the polarization angle is varied from 0 degrees to 90 degrees,(More)
We have developed a novel phase-resolved optical coherence tomography (OCT) and optical Doppler tomography (ODT) system that uses phase information derived from a Hilbert transformation to image blood flow in human skin with fast scanning speed and high velocity sensitivity. Using the phase change between sequential scans to construct flow-velocity imaging,(More)
We used a novel phase-resolved optical Doppler tomographic (ODT) technique with very high flow-velocity sensitivity (10microm/s) and high spatial resolution (10microm) to image blood flow in port-wine stain (PWS) birthmarks in human skin. In addition to the regular ODT velocity and structural images, we use the variance of blood flow velocity to map the PWS(More)
The properties of the leader-laggard chaos synchronization (LLCS) in two mutually coupled external-cavity semiconductor lasers are studied systematically. We theoretically analyze the general conditions for the LLCS based on the symmetric operation mechanism and numerically investigate the influences of operation parameters, the mismatch robustness, the(More)
We numerically analyze the effect of an injection current on the synchronization and communication features of two chaotic external cavity semiconductor lasers in a closed-loop configuration. The simulation results demonstrate that, by moderately increasing the injection current, the efficient bandwidth of the chaotic carrier would be broadened, high(More)
The chaotic unpredictability of vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated optical feedback is evaluated quantitatively via the normalized permutation entropy H. The effect of polarization mode competition (PMC) is explored. For weak PMC, the H for X-polarization mode, Y-polarization mode, and total output are close to each(More)
We report on the realization of a hybrid chaos-based communication scheme using three chaotic semiconductor ring lasers (SRLs). In this scheme, two slave SRLs (S-SRLs) are identically driven by a master SRL (M-SRL) subject to delayed optical feedback. Under proper conditions, the S-SRLs are completely synchronized with each other due to the symmetric(More)
The time-delay (TD) signatures of chaos in semiconductor ring lasers with cross mutual injection are investigated numerically. The TD signature is quantified via auto-correlation function. The injection parameter regions contributing to successful TD concealment are identified. It is shown that, higher injection strengths can be utilized for larger(More)
In this paper, a novel photonic-assisted Doppler frequency shift (DFS) measurement scheme based on an integrated dual-polarization Mach-Zehnder modulator is presented. In the proposed scheme, the DFS to be identified is transformed into a low-frequency electrical signal through an optical frequency-conversion link. The value of the DFS can be acquired by(More)
A simultaneous unidirectional and bidirectional chaos-based optical communication scheme based on a hybrid coupling semiconductor laser system that consists of one center semiconductor laser (CSL) and multiple side semiconductor lasers (SSLs) is proposed numerically. In this scheme, the SSLs oriented in a linear chain mutually couple with the adjacent SSLs(More)