Noise in supercontinuum generated using PM and non-PM tellurite glass all-normal dispersion fibers.

Intensity fluctuations in supercontinuum generation are studied in polarization-maintaining (PM) and non-PM all-normal dispersion tellurite photonic crystal fibers. Dispersive Fourier transformation is used to resolve the shot-to-shot spectra generated using 225-fs pump pulses at 1.55 µm, with experimental results well reproduced by vector and scalar numerical simulations. By comparing the relative intensity noise for the PM and non-PM cases, supported by simulations, we demonstrate the advantage of the polarization-maintaining property of the PM fibers in preserving low-noise dynamics. We associate the low-noise in the PM case with the suppression of polarization modulation instability.

Ultra-low-noise supercontinuum generation with a flat near-zero normal dispersion fiber.

A pure silica photonic crystal fiber with a group velocity dispersion (ß2) of 4 ps2/km at 1.55 µm and less than 7 ps2/km from 1.32 µm to the zero dispersion wavelength (ZDW) 1.80 µm was designed and fabricated. The dispersion of the fiber was measured experimentally and found to agree with the fiber design, which also provides low loss below 1.83 µm due to eight outer rings with increased hole diameters. The fiber was pumped with a 1.55 µm, 125 fs laser and, at the maximum in-coupled peak power (P0) of 9 kW, a 1.34-1.82 µm low-noise spectrum with a relative intensity noise below 2.2% was measured. The numerical modeling agreed very well with the experiments and showed that P0 could be increased to 26 kW before noise from solitons above the ZDW started to influence the spectrum by pushing high-noise dispersive waves through the spectrum.

AMC 12 atomic mass compilation data extrapolated for atomic masses of nuclei far from the valley of stability.

The experimental mass data from the Atomic Mass Compilation - 2012 (AMC12) has been analyzed for two-neutron separation energies ([Formula: see text]), two-proton separation energies ([Formula: see text]), double-beta decay energies ([Formula: see text]), and four-beta decay energies ([Formula: see text]) and plotted against neutron number and mass number, respectively. A new weighted slope method of extrapolation, tested for known and new mass measurements, has been used to obtain the extrapolated mass values with better precision for more than 1100 nuclei far from the valley of stability, out of which more than 100 are being reported for the first time. A comparison has been made with five of the popular mass models with reference to experimental extrapolated masses from the present work and the Atomic Mass Evaluation 2016 (AME16). The extrapolated experimental atomic mass data will be very useful for both experimentalists and mass-model theoreticians, as well as in simulations of astrophysical r-processes.

Shot-noise limited, supercontinuum-based optical coherence tomography.

We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 µm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and 320 MHz repetition rate. We show that the low-noise of the ANDi fiber-based supercontinuum source improves the OCT images significantly in terms of both higher contrast, better sensitivity, and improved penetration. From SD-OCT imaging of skin, retina, and multilayer stacks we conclude that supercontinuum-based SD-OCT can enter the domain of shot-noise limited detection.

Novel optical gyroscope: proof of principle demonstration and future scope.

We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives.