We design an ytterbium-doped large pitch photonic quasi-crystal fiber (PQF) for amplifying high-energy ultrashort laser pulses. The proposed fiber exhibits unique properties such as very large mode area (4660 μm 2), less attenuation (0.42 dB/km), high overlapping factor (0.55 for the fundamental mode), and low bending loss. These properties help amplify with high-average power ultrashort pulses with less distortion and high efficiency. To meet these requirements, we design a fiber with optimum gain filtering as well as loss filtering. From the numerical simulation of the analytical model, we confirm that the large pitch PQF plays an indispensable role in amplifying high-energy ultrashort pulses. © 2012 IEEE.

Sivabalan S

Department of Instrumentation

School of Electrical Engineering

Vellore Campus

Raina J.P.

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Large Pitch Photonic Quasi-Crystal Fiber Amplifier

IEEE Photonics Journal

A silica quasi-periodic clad leakage channel fiber (LCF) is proposed to enhance the mode filtering characteristics with large effective mode area (Aeff). In this work, we explore the fiber characteristics, namely, bending loss (BL),&nbsp;Aeff&nbsp;and differential loss for different micro-structured cladding LCF designs. Of the various LCFs, an octagonal core&ndash;octagonal quasi-periodic clad LCF provides a large loss ratio (&gt;103) between fundamental mode (LP01&nbsp;mode) and most competitive higher order mode (LP11&nbsp;mode). Further, it exhibits a high BL of 66.48&nbsp;dB/m for LP11&nbsp;mode by resonance mode filtering along with a bend induced modal discrimination at 1.05&nbsp;&mu;m wavelength. The detailed numerical results reveal that the differential loss ratio goes high when the effective index of the second ring of eight sectional elements in a quasi-periodic cladding is scaled up and the&nbsp;Aeff&nbsp;increases when it is scaled down. Thus, the proposed octagonal core&ndash;octagonal quasi-periodic clad LCF exhibits a large mode area of 1161&nbsp;&mu;m2, a low BL of 0.04&nbsp;dB/m for the LP01&nbsp;mode and a high differential loss ratio of 1624 between LP11&nbsp;and LP01&nbsp;modes at a critical bending radius of 15&nbsp;cm with an air-filling ratio of 0.4. These interesting properties of the LCF could pave way for developing a compact high power&nbsp;<a href="https://www.sciencedirect.com/topics/physics-and-astronomy/fiber-lasers" title="Learn more about Fiber Lasers from ScienceDirect's AI-generated Topic Pages">fiber laser</a>&nbsp;system.

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Optics Communications

Influence of quasi-periodic cladding on single mode behavior in a leakage channel fiber: Towards the enhancement of modal discrimination and low bending loss of the LP 01 mode

We report a large mode area (LMA), Ge11.5As24Se64.5 six-fold symmetry quasi-periodic dual cladding leakage channel fiber (LCF) for supercontinuum generation (SCG) from 2 to 15μm wavelengths. The proposed LMA fiber exhibits single-mode behavior by means of higher order mode delocalization for the entire wavelengths. Besides, the LCF possesses two zero dispersion wavelengths at 4.36 and 14.16μm. Indeed, we numerically demonstrated the spectral broadening of continuum for the first time from 2 to 15μm in the quasi-periodic dual cladding LCF for a length of 10 mm. It is observed that the red-shifted soliton at the centre wavelength of 9.42μm obtain an energy of 0.164 nJ for a low input energy of 0.2 nJ. Further, the SCG in the proposed LCF attains a high conversion efficiency of 82 % at the solitonic spectrum and broadest spanning from 2 to 15μm for the low input energy of 0.2 nJ. Thus, the proposed LCF-based SC source is the best choice for the applications, such as optical sensing, optical communication, food quality monitoring, and early cancer diagnostics. © 1965-2012 IEEE.

IEEE Journal of Quantum Electronics

Efficient Wideband Supercontinuum Generation in Mid-IR Wavelengths Using Large Mode Area Quasi-Periodic Cladding Leakage Channel Fiber With Low Input Energy

We report a polarization maintaining chalcogenide (ChG) photonic quasicrystal fiber (PQF) for wide-band mid- IR (MIR) supercontinuum (SC) generation. The numerical demonstration of SC generation in the proposed PQF spans from 2 to 15 μm wavelengths for a pulse power of 2 kW. Besides, the proposed PQF offers a high birefringence (10-3 to 10-2) from 3.5 to 15 μm wavelengths and exhibits a low confinement loss (10-7 to 10-1) for the wavelengths from 2 to 15 μm with single mode behavior. The proposed Ge11.5As24Se64.5 PQF is designed with zero dispersion wavelengths (ZDWs) at 4.33 and 4.46 μm for X and Y polarized modes within the wavelength range of 2-15 μm. The polarized spectral broadening of the continuum is realized for the first time from 2 to 15 μm using the proposed PQF with a length of 8 mm. Hence, the two orthogonally polarized modes allow the high degree of freedom in tuning the properties of the SC. Thus, the proposed PQF-based SC source is a good candidate for applications such as optical sensing, frequency metrology, and optical tomography. © 2017 Optical Society of America.

Applied Optics

Wide-band supercontinuum generation in mid-IR using polarization maintaining chalcogenide photonic quasi-crystal fiber

Using finite-element method, we propose a photonic quasi-crystal fiber-based refractive index biosensor (PQF-RIBS), which works based on the surface plasmon polariton. We determine the loss spectra for two different variations of the refractive index of analyte, na. From the detailed numerical analysis, we find that the PQF-RIBS exhibits a maximum refractive index sensitivity of 6000 nm/RIU and a resolution of 1.6 × 10-6 RIU when na is increased from 1.45 to 1.46. Besides, this sensor does exhibit the negative refractive index sensitivity of -4000 nm/RIU and a resolution of 2.5 × 10-6 RIU for a sensing range from 1.52 to 1.53. Furthermore, we carry out selective filling of liquid in the selective holes of the proposed biosensor for a sensing wavelength range from 900 to 1200 nm. Finally, we also study the influence of the structural parameters, namely, diameter of the core and diameter of the air holes in the cladding over the loss spectra of a fundamental mode for a particular na of 1.47. © 2016 IEEE.

IEEE Sensors Journal

Designing a Biosensor Using a Photonic Quasi-Crystal Fiber

In this work, we design a novel, index guiding, silica core photonic quasi-crystal fiber (PQF) of 6, 8 and 10-folds for a wide range of operating wavelengths from 0.6 to 3&nbsp;μm. Further, we explore the various optical properties, namely, birefringence, dispersion, and nonlinearity for all the folds. Of all the folds, 10-fold PQF provides a low dispersion of −2.4765&nbsp;ps2&nbsp;km−1, a high nonlinearity of 22&nbsp;W−1&nbsp;km−1, admissible level of a less birefringence of 3.8&nbsp;×&nbsp;10−5 and confinement loss of 0.30446&nbsp;dB/cm at 1.06&nbsp;μm. These optical properties form the crucial requirements for the generation of few cycle laser pulses. Besides, we calculate the quality factor (Q) of the fundamental mode for all the folds and report a maximum quality factor of 0.9961 for the 10-fold PQF at 1.06&nbsp;μm wavelength.

Infrared Physics & Technology

Design of a photonic quasi-crystal fiber for the generation of few cycle laser pulses

We propose a fiber stretcher for stretching the high-energy ultrashort pulses which require high dispersion and large mode area to secure high stretching ratio and for ensuring distortionless pulses. In this line, we suggest a novel design of photonic quasi-crystal fiber (PQF) to achieve the desired high normal group velocity dispersion (GVD) of 1000 ps2/km at 1.06 μm and inner core effective mode area as 35 μm2. These unique properties have been exploited to achieve a high stretching ratio (&gt;105) as well as less nonlinearity, which, in turn, results in a distortionless fiber stretcher for an Yb-doped high-energy ultrafast fiber laser system based on chirped pulse amplification. © 2006 IEEE.

Journal	Data powered by TypesetIEEE Photonics Journal
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers (IEEE)
ISSN	19430655
Open Access	No