-
[show abstract]
[hide abstract]
ABSTRACT: The group velocity dispersion (GVD) characteristics of a holey fibre design with a high index, slot structure in the core region are modified by introducing a simple cladding structure with a few large air holes. Our simulation results show that ultra-small mode effective areas and a high nonlinearity of the TE mode can be achieved, which is confined in the narrow slot by two silicon slabs in a glass fibre. This slot structure can be optimized to simultaneously achieve a very small Aeff and a single-TE-mode propagation. On the other hand, the proposed cladding can significantly reduce and flatten the large negative GVD of the slot structure, which could improve the nonlinear efficiency and interaction length for nonlinear applications. Our results indicate that an ultra-small Aeff of 0.16 µm2 and a flattened and reduced GVD with less than 10 ps nm − 1 km − 1 dispersion ripple within a 40 nm range at the 1.55 mm wavelength are achievable.
Journal of optics 09/2010; 12(11):115502. · 1.57 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple photonic crystal fiber (PCF) design with a rectangular array of four airholes in the core region and a traditional circular-airhole cladding is proposed in this work. The modal birefringence is induced by the asymmetry of the rectangular distribution of four airholes and/or the elliptical shape of the holes. The traditional symmetric cladding structure results in good confinement loss performance by limiting the light in the core region. Therefore, the proposed design enables simultaneous realization of high birefringence and low confinement loss. Simulations based on the full-vector finite element method (FEM) with anisotropic (PML) show that ultrahigh single-mode birefringence (~ 10<sup>-2</sup>) and ultralow confinement losses ( < 0.002 dB/km) can be achieved at 1.55 mum wavelength. Dependence study of the birefringence and losses on several key parameters is also provided. Compared to previously studied PCF with asymmetric core or cladding structures, by having just four relatively large airholes in the core, this design could be much easier to be implemented with even better performance.
Journal of Lightwave Technology 09/2009; · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A holey fiber design with a high index nanostructure that can achieve an effective mode area not in excess of 0.3 mum<sup>2</sup> and a flat dispersion at the 1.55 mum band is proposed and studied.
Lasers and Electro-Optics, 2009 and 2009 Conference on Quantum electronics and Laser Science Conference. CLEO/QELS 2009. Conference on; 07/2009
-
[show abstract]
[hide abstract]
ABSTRACT: We report the experimental comparison of 10.7-Gb/s duobinary transmissions using generic Reed-Solomon forward error correction (FEC) and an enhanced FEC. The coding gains of the two FECs after transmission over a dispersion-uncompensated 200-km standard single-mode fiber (SSMF) link are found to be much larger than those quoted in ideal case, with the enhanced FEC further outperforming the generic FEC by /spl sim/3.5 dB. Numerical simulations show reasonable agreement with the experimental results.
IEEE Photonics Technology Letters 09/2003; · 2.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Polarization-mode-dispersion tolerance of a low-pass filter duobinary modulation format is investigated. With the optimum residual dispersion, the optical signal-to-noise ratio penalty at a differential group delay of 40 ps is measured to be 1 dB (at BER=6/spl times/10/sup -5/): 1.5 dB less than that without residual dispersion in a 10.7-Gb/s duobinary transmission. Numerical simulations show reasonable agreement with the experimental results.
IEEE Photonics Technology Letters 08/2003; · 2.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We report a novel design of photonic crystal fiber (PCF) with a rectangular array of four closely-spaced, highly elliptical air holes in the core region and a circular-air-hole cladding. The proposed PCF is able to support ultra-wideband single-polarization single-mode (SPSM) transmission from the visible band to the near infrared band. With the aid of the inner cladding formed by the central air holes, one polarization of the fundamental mode can be cut off at very short wavelengths and ultra-wideband SPSM propagation can be achieved. The inner cladding also suppresses the higher order modes and allows large air filling fraction in the outer cladding while the proposed fiber remains SPSM, which significantly reduces the mode effective area and the confinement loss. Our simulation results indicate that the proposed PCF has a 1540 nm SMSP range with < 0.25 dB/km confinement loss and an effective area of 2.2 Pm 2 . Moreover, the group velocity dispersion (GVD) of the proposed PCF can also be tuned to be flat and near zero at the near infrared band (~800 nm) by optimizing the outer cladding structure, potentially enabling many nonlinear applications.
-
[show abstract]
[hide abstract]
ABSTRACT: a b s t r a c t We report a novel design of photonic crystal fiber (PCF) with a rectangular array of four closely-spaced, highly elliptical air holes in the core region and a circular-air-hole cladding. The proposed PCF is able to support ultra-wideband single-polarization single-mode (SPSM) transmission from the visible band to the near infrared band. With the aid of the inner cladding formed by the central air holes, one polarization of the fundamental mode can be cut off at very short wavelengths and ultra-wideband SPSM propagation can be achieved. The inner cladding also suppresses the higher order modes and allows large air filling fraction in the outer cladding while the proposed fiber remains SPSM, which significantly reduces the mode effective area and the confinement loss. Our simulation results indicate that the proposed PCF has a 1540 nm SMSP range with <0.25 dB/km confinement loss and an effective area of 2.2 lm 2 . More-over, the group velocity dispersion (GVD) of the proposed PCF can also be tuned to be flat and near zero at the near infrared band ($800 nm) by optimizing the outer cladding structure, potentially enabling many nonlinear applications.
-
[show abstract]
[hide abstract]
ABSTRACT: An all-optical regeneration scheme for DQPSK and QPSK signals using phase-sensitive amplifiers (PSAs) is studied and its effectiveness is investigated through numerical simulations. By leveraging the ability of PSAs to provide phase and amplitude regenerative amplification, we show significant simultaneous suppression of both phase and amplitude noises of (D)QPSK signals under optimized conditions. The reduction in the phase noise variance of a noise-corrupted DQPSK signal obtained by one such regenerative amplification can be as large as ∼5.5 folds, showing its good potential for distributed optical regeneration of (D)QPSK signals.
Optics Communications.
