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We experimentally evaluate the performance of underwater wireless optical communication (UWOC) links in the presence of different air bubbles. Air bubbles of different sizes and densities are generated by using an air pipe in conjunction with a submersible water pump of variable flow rate that help break up large bubbles into smaller bubbles. Received signal intensity measurements show that bubbles...
Hybrid amplifier is a promising technology and give a better performance because it can handle network with a high traffic. Hybrid amplifier is used to optimize gain bandwidth of WDM-based system. Optimization of the hybrid amplifier (Raman-EDFA) make gain spectrum being around the same reinforcement intensity by lowering the gain flatness of 4.3 dB to 0.01 dB with an average gain of about 25.7 dB...
In this paper, we investigate the performance of unrepeatered optical transmission using nonlinear compensation, and dynamic equalization enhanced by forward error correction (FEC) feedback. The digital back-propagation (DBP) algorithm is used for nonlinear compensation, while error correction is provided by spatially-coupled low-density parity-check (SC-LDPC) codes. The technique is experimentally...
Their inherently broadband gain and high value of the third order nonlinearity makes quantum cascade lasers (QCLs) ideal candidates for frequency comb generation in the terahertz (THz) and mid-infrared (midIR) spectral ranges. In recent years, it has been demonstrated that free running QCLs can produce broad comb spectra, even without any special endeavour to induce phase-locking of the lasing modes...
The emission and propagation of light in disordered media has always been a topic of interest in science, mainly because in nature this is the most common way of light emission and propagation. This research topic received a particular attention after the report of the first highly efficient random laser (RL) [1]. Indeed a large number of investigations discussing the fundamentals and the applications...
The Petawatt Field Synthesizer (PFS) is an OPCPA driven light source that is currently being developed at the Max-Planck-Institut für Quantenoptik in Garching, Germany. The target parameters are few-cycle, waveform-controlled light pulses with a repetition rate of 10 Hz and a peak power in the Petawatt regime [1]. The system relies on a cascaded broadband OPCPA that is pumped by a picosecond, all-diode-pumped...
We demonstrate a reconfigurable, software-controlled, C-band optical power distribution system leveraging a 1×7 cascaded microring-based silicon photonic device. The thermo-optic effect and the spectral response of each ring is characterized and utilized in FPGA-based control plane algorithm to achieve precise power distribution profiles.
We demonstrate a scheme for correcting the angular dispersion of the 3.1- $\mu$m idler beam from a high repetition rate, KTiOAsO$_4$ (KTA) based noncollinear optical parametric amplifier pumped at 1.03 $\mu$m and seeded by broadband signal pulses at 1.55 $\mu$m. Following angular dispersion correction, successful temporal chirp compensation was possible, and a close to transform-limited pulse duration...
In this paper, we show an approach to build deep learning algorithms for recognizing signals in distributed fiber optic monitoring and security systems for long perimeters. Synthesizing such detection algorithms poses a non-trivial research and development challenge, because these systems face stringent error (type I and II) requirements and operate in difficult signal-jamming environments, with intensive...
A novel thresholder based on cross-gain modulation (XGM) effect in a distributed-feedback (DFB) semiconductor laser combined with offset optical filtering is proposed and demonstrated. To the best of our knowledge, this is the first XGM effect-based thresholder that is operated by optical injection of a DFB laser. In this scheme, a DFB laser without an isolator is the key component, which costs less...
Degradation of phase-conjugated twin waves on non-degenerated fiber parametric phase-sensitive amplifier repeaters due to pump-phase fluctuation is numerically investigated. From simulation results, an acceptable phase error on pump-phase locking is clarified.
We have demonstrated a 4×10 Gb/s RZ-DPSK wavelength multicasting using Raman amplification-based compressor with adjustable pulsewidth down to around 7.89 ps. Bit-error-rate at 10−9 of multicast signals are achieved with low power penalties.
Optimum design of high-energy parametric down-conversion schemes mandate investigation of nanosecond laser-induced damage threshold in KTiOPO4 and Rb:KTiOPO4 at 1.064 μm and 2 μm. A surface damage threshold of 10 J/cm2 at 2 μm was determined for both materials.
Optical phase lock loop circuit for non-degenerate parametric phase sensitive amplifiers with wide signal-idler light frequency spacing is proposed. The proof-of-principle experiment is successfully demonstrated for 40-GHz spaced signal-idler lights using 5-GHz beat signals.
We demonstrate a protocol enabling the generation of large coherent state superpositions with unprecedented preparation rate. It is optimally using expensive non-Gaussian resources to build up only the core non-Gaussian part of the state.
We exploit the inherent mode competition in a laser resonator to solve in real time the major coherent control problem — how to shape a pulse that will dump a general wave-packet in to a single target state.
We present a new phase-locking technique based on weak pump depletion. It allows for the first experimental realization of a pump-phase lock of an optical parametric oscillator by reading out the pre-existing phase information in the pump field. No degradation of the detected squeezed states occurs.
A multi-party quantum key distribution scheme is experimentally demonstrated by utilizing a poled fiber-based broadband polarization-entangled source and dense wavelength-division multiplexing. Entangled photon pairs are delivered over 40-km of fiber, with secure key rates of more than 20 bits/s observed.
We describe the process of difference-frequency generation of optical radiation from X-ray pulses. We find that the efficiency is orders of magnitude higher than similar effects, and highlight its potential application to probe atomic-scale structures.
Developed a statistical approach, which provides information about the cooling time of an atomic ensemble without directly solving a dynamic problem. The effect of velocity saturation of laser cooling with increasing Rabi frequency was found.
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