Saghaei's papers published in 2018

[1] H. Saghaei, “Dispersion-engineered microstructured optical fiber for mid-infrared supercontinuum generation,” Applied Optics, vol. 57, no. 20, p. 5591, 2018, doi: 10.1364/ao.57.005591.

Due to the large scientific and technical interest in the mid-infrared (MIR) spectral region, and the limitations of MIR light sources, we focus on the generation of a broad supercontinuum inside a short piece of As2Se3 microstructured optical fiber (MOF) with a square lattice. This is accomplished by filling the holes in the innermost ring of the proposed MOF with Ge33As12Se55 to produce ultra-flat and near-zero dispersion. Simulations reveal that, by launching 100 fs input pulses centered at 𝜆0=6.2 μm with a peak power of 2 kW into the MOF, an optical spectrum as wide as 9.5 μm will be achieved. This spectrum is a suitable source for MIR applications such as spectroscopy, food quality control, and gas sensing.

[2] M. Kalantari, A. Karimkhani, and H. Saghaei, “Ultra-Wide mid-IR supercontinuum generation in As2S3 photonic crystal fiber by rods filling technique,” Optik, vol. 158, pp. 142–151, 2018, doi: 10.1016/j.ijleo.2017.12.014.

In this paper, we study the fluid infiltration approach and rod filling technique for dispersion engineering of a photonic crystal fiber (PCF) composed of As2S3-Chalcogenide glass. The numerical results based on finite difference time domain method reveal that when air holes of the innermost ring in a PCF are infiltrated with suitable fluids or filled by glass rods, ultra-flattened near-zero dispersions with high nonlinearities will be achieved over a wide mid-IR wavelength range. The simulations demonstrate that when a 100 fs input optical pulse of 20 kW peak power and central wavelength of 2.5 μm is launched into a 10 mm length of the As2S3 PCF filled by PBG-08 rods, a ripple-free spectral broadening as wide as 9 μm from 1 to 10 μm can be obtained which is used as a suitable source for Mid-IR applications in molecular fingerprint region such as medical diagnosis of diseases, and drug detection.

[3] R. Raei, M. Ebnali-Heidari, and H. Saghaei, “Supercontinuum generation in organic liquid–liquid core-cladding photonic crystal fiber in visible and near-infrared regions,” Journal of the Optical Society of America B, vol. 35, no. 2, p. 323-330, 2018, doi: 10.1364/josab.35.001545.

In this paper, we propose a liquid core-cladding photonic crystal fiber (PCF), which is engineered with different available organic optofluidics, to generate supercontinuum in the visible and near-infrared regimes by using the symmetrized split-step Fourier method. Simulations reveal that in response to launching 50 fs input pulses of 10 kW peak power, centered about 𝜆0=1032 and 1560 nm, into a 10 mm long liquid core-cladding PCF, maximum 2 μm supercontinua from 500 to 2500 nm can be achieved. Our numerical study is important for the new field of visible and near-IR supercontinuum generation in liquid-core optical fibers.

[4] A. Ghanbari, A. Kashaninia, A. Sadr, and H. Saghaei, “Supercontinuum generation with femtosecond optical pulse compression in silicon photonic crystal fibers at 2500 nm,” Optical and Quantum Electronics, vol. 50, no. 11, 2018, doi: 10.1007/s11082-018-1651-5.

In this paper, femtosecond optical pulses compression and supercontinuum generation in a triangular silicon photonic crystal fiber at 2500 nm are investigated. A region of large minimum anomalous group velocity dispersion, negligible higher-order dispersions, and unique nonlinearity of silicon are used to demonstrate compression of 100 fs initial input optical pulses to 2.5 fs and ultra-broadband supercontinuum generation with very low input pulse energy over short distances of the fiber.

[5] A. Kowsari and H. Saghaei, “Resonantly enhanced all-optical switching in microfibre Mach–Zehnder interferometers,” Electronics Letters, vol. 54, no. 4, pp. 229–231, 2018, doi: 10.1049/el.2017.4056.

We propose an all-optical switch based on a microfibre Mach–Zehnder interferometer (MMZI) in which the MMZI is considered with a microfibre loop resonator (MLR) in one arm of it. The authors numerically demonstrate that the enhanced phase shift of the MLR near its resonance wavelengths can be used for constructive/destructive interference and switching functionality of the MMZI. The calculated switching threshold power of the switch is about 2 mW, which can be further reduced by the use of an MLR with more finesse, and the rising and falling times are computed with 21 and 91 ps, respectively. The natural connection to silica single-mode fibers, easy configuration, and high speed make it a suitable choice for all-optical signal processing and communications applications.