Showing 3 results for Singh
G. Singh, R.p. Yadav, V. Janyani,
Volume 4, Issue 1 (International Journal of Optics and Photonics (IJOP) Vol. 4, No. 1, Winter-Spring 2010)
Abstract
The main emphasis in developing DOS has been on achieving low crosstalk (CT). CT in the order of -30 dB is acceptable in conventional DOS and below that value is hard to achieve. Relatively low drive voltage (or power requirements) is also necessary to optimized DOS. This paper depicts the design of Y-branched digital optical switches (DOS) with optimized on-chip area coverage, reduced driving voltage and cross talk. The proposed switch is designed using channel profile of proton exchanged lithium niobate substrate. The electro-optic effect of the material has been investigated from the DOS operation.
A. Gaur, D. Sharma, P. Gaur, B.p. Malik, N. Singh,
Volume 4, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 4, No. 2, Summer-Fall 2010)
Abstract
The Photoexcited carrier lifetime (τ) and peak to valley transmission difference (ΔTp-v) in direct and indirect band gap crystals has been investigated by the use of single beam open and closed aperture z-scan technique using frequency doubled Nd:YAG laser. The peak to valley transmission difference (ΔTp-v) is found to be of the order of 10-2 in case of direct band gap crystals and of the order of 10-3 in case of indirect band gap crystals. The carrier life time (τ) is found to be in nanoseconds range in case of direct band gap crystals and picoseconds range in case of indirect band gap crystals. Lower value of (τ) and (ΔTp-v) in case of indirect band gap crystals can be attributed to the reduction in the value of carrier density (N) and small value of nonlinear phase shift ( Δϕ ),respectively.
S.s. Mishra, Vinod Kumar Singh,
Volume 5, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 5, No 2, Summer-Fall 2011)
Abstract
A novel design of Dual-Core Photonic Crystal Fiber (DC-PCF) with silica-air microstructures is proposed in this paper. Nonlinearity and confinement loss of DC-PCF are evaluated by using a Full-Vectorial Finite Element Method (FV-FEM) successfully. By optimizing the geometry of three ring DC-PCFs, a high nonlinearity (52w-1km-1) and low confinement loss (0.001dB/km) can be achieved at 1.55μm wavelength when diameter to pitch ratio (d/Λ) is 0.70.
