Diamond unit cell photonic crystal fiber with high birefringence and low confinement loss based on circular air holes.

We propose a novel photonic crystal fiber (PCF) design with high birefringence and low confinement loss based on a diamond unit cell. Unit cell is a degree of freedom of PCF design, and highly asymmetric diamond unit cell can deliver both high birefringence and low confinement loss. In our fiber design, each diamond unit cell consists of two different sizes of circular air holes in a conventional hexagonal lattice, which can enhance the confinement loss with increased birefringence and can overcome the previous fabrication challenges of elliptic air hole PCFs due to the all-circular air hole structure. The optimized design shows high birefringence of 6×10(-3) over S, C, and L bands while maintaining low confinement loss.

Photon-counting three-dimensional integral imaging with compression of elemental images.

In this paper, we present lossless compression of elemental images in photon-counting integral imaging. In order to verify the performance of the compression method applied to low light level three-dimensional (3D) integral imaging, we compute the correlation coefficient and peak to mean square error (PSNR) as metrics for 3D scene reconstruction integrity. We show quantitatively via experiments that a considerable compression of the elemental images in photon-counting integral imaging may be achievable without significant loss in the performance in terms of correlation and PSNR metrics. To the best of our knowledge, this is the first report on applying lossless compression algorithms in photon-counting 3D computational integral imaging.

Elliptical defected core photonic crystal fiber with high birefringence and negative flattened dispersion.

We propose a novel design of photonic crystal fiber (PCF) using an elliptical air hole in the core as a defected core in order to enhance the performance of modal birefringence and to control the properties of chromatic dispersion at the same time. From the simulation results, it is shown that the proposed fiber has high birefringence up to the order of 10(-2), negative flattened chromatic dispersion in a broad range of wavelengths, and low confinement loss less than that of the single mode fiber. The outstanding advantage of the proposed PCF is that high birefringence, negative flattened dispersion, and low confinement loss can be achieved just by adding a small sized elliptical air hole in the core to the elliptical air hole PCF, especially at the same time.

A hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks.

We propose and experimentally demonstrate a hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks. Dynamic function is implemented by mechanically tuning the Fourier encoder/decoder for optical code division multiple access (OCDMA) encoding/decoding. Wavelength division multiplexing (WDM) is utilized for node assignment and 4-chip Fourier code recovers the matched signal from the codes. For an optical source well adapted to WDM channels and its short optical pulse generation, reflective semiconductor optical amplifiers (RSOAs) are used with a fiber Bragg grating (FBG) and gain-switched. To demonstrate we experimentally investigated a two-node hybrid WDM/OCDMA ring with a 4-chip Fourier encoder/decoder fabricated by cascading four FBGs with the bit error rate (BER) of <10(-9) for the node span of 10.64 km at 1.25 Gb/s.

Modified rectangular lattice photonic crystal fibers with high birefringence and negative dispersion.

We propose a modified rectangular lattice PCF and numerically investigate its birefringence and dispersion. Based on the plane wave expansion method, it is shown that the proposed structure provides high birefringence and negative dispersion. Numerical results show that the birefringence of the modified PCF reaches 10(-2) and the leakage loss is about 1000 times smaller than that of an original rectangular PCF because the modification gives rise to the strong confinement of guided modes. Dispersion and its slope are also negative over the C band.