ABSTRACT
We demonstrate continuously tunable optical delays as large as 1.1 micros range for 10 Gb/s NRZ optical signals based on four-wave mixing (FWM) process in silicon waveguide. The large delay range is made possible by a novel wavelength-optimized optical phase conjugation scheme, which allows for tunable dispersion compensation to minimize the residual group-velocity dispersion (GVD) for the entire tuning range.
Subject(s)
Refractometry/instrumentation , Silicon/chemistry , Telecommunications/instrumentation , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and Specificity , Time FactorsABSTRACT
Flexible endoscopes commonly use coherent fiber bundles with high core density to facilitate in vivo imaging. Small, closely spaced cores are desired for achieving a high number of resolvable pixels in a small diameter fiber bundle. On the other hand, closely spaced cores potentially lead to strong core-to-core coupling. Based on numerical simulations, it was previously explained that image fiber bundles can successfully transmit images because of nonuniformities in the core size that reduce coupling. In this paper, we show numerically and experimentally that, due to the randomness of the structural nonuniformity, significant core-to-core coupling still exists in fiber bundles that are routinely used for imaging. The coupling is highly dependent on the illumination wavelength and polarization state. We further show that the resolution achievable by a fiber bundle depends not only on the core density, but also on the inter-core coupling strength. Finally, we propose that increasing the core-cladding index contrast is a promising approach to achieve a fiber bundle with low core coupling, high core density, and effectively single moded propagation in individual cores.
Subject(s)
Endoscopes , Endoscopy/methods , Computer Simulation , Diagnostic Imaging/instrumentation , Diagnostic Imaging/methods , Equipment Design , Fiber Optic Technology , Humans , Image Processing, Computer-Assisted , Lasers , Light , Models, Theoretical , Optical Devices , Optical Fibers , RefractometryABSTRACT
We demonstrate a technique for generating large, all-optical delays while simultaneously minimizing pulse distortion by using temporal phase conjugation via four-wave mixing in Si nanowaveguides. Using this scheme, we achieve continuously tunable delays over a range of 243 ns for 10 Gb/s NRZ data.
