The bandwidth of planar waveguide grating couplers is theoretically investigated based on the rigorous grating theory. We observe that the bandwidth behavior is not only determined by the grating coupler intrinsic properties, but also affected by the fiber parameters such as position, beam waist and Numerical Aperture. The rigorous bandwidth formula is derived. By analyzing the formula, several...

The use of grating couplers to couple light near vertically in and out of optical slab or film waveguides represents an attractive method to interface optical fiber to photonic ICs. Newly developed fiber technologies exploiting vector mode polarization and orbital angular momentum (OAM) are inherently threedimensional and interfaces for such beams require the solution of fully general 3D models...

In this Letter, we propose general optimization methods to design broadband high-efficiency grating couplers for planar waveguides. We attribute the coupling bandwidth to the mismatch of effective indices between the diffracted beam and the actual grating structure around the operation wavelength for fiber to waveguide excitation. The coupling bandwidth formula is deduced. A simple parameter-se...

We experimentally demonstrate 2 × 2 and 3 × 3 fused fiber couplers made from dual mode fiber. A unique mode dependent power transfer characteristics as a function of pulling length is obtained that support various optical functionalities. Exploiting this we demonstrate several devices of interest for mode division multiplexed data transmission including LP11 mode filter, LP11 mode tap coupler, ...

A novel method for100Gbpsall-optical OFDM using Discrete Cosine Transform in a Radio-Over-Fiber link is proposed. The system is designed simply using both symmetric and asymmetric passive optical couplers. DCT is achieved all-optically by adjusting the length and splitting ratio of the couplers. The performance of the system is compared with all-optical OFDM based on Discrete Fourier, Discrete ...

Basic asymmetric behavior is experimentally observed in a polished polarization-maintaining fiber coupler. As the two half-couplers are made to slide on top of each other, the output extinction ratio exhibits relatively large variations whose forms depend on the fiber that is selected for the input. We propose that a local distortion of the fiber birefringent axes, which could be caused by the ...

The silicon photonics market has grown rapidly over recent decades due to the demand for high bandwidth and data-transfer capabilities. Silicon leverage well-developed semiconductor fabrication technologies combine various photonic functionalities on same chip. Complicated integrated circuits require a mass-producible packaging strategy with broadband, coupling efficiency, fiber-array fiber-to-...

We study nonlinear modes of dual-core photonic crystal fiber couplers made of a material with the focusing Kerr nonlinearity. We find numerically the profiles of symmetric, antisymmetric, and asymmetric nonlinear modes and analyze all-optical switching generated by the instability of the symmetric mode. We also describe elliptic spatial solitons controlled by the waveguide boundaries.