Ilya Vorobeichik

Non-evanescent adiabatic directional coupler

A directional coupling mechanism based on an adiabatic coupling between three optical modes is suggested. The optical power transfer between two waveguides which are far apart is mediated by adiabatic coupling between zero-order optical modes of the individual waveguides and a high-order intermediate mode. The analytical model for an adiabatic three-mode coupling based on a scalar wave equation is presented. The directional coupling via the adiabatic mode coupling between copropagating modes is described and compared with a nonadiabatic directional coupling assisted by periodic perturbation. It is shown that adiabatic directional coupling has much less sensitivity to the mode parameters and to the wavelength.

Novel wide-band low-PDL integrated variable optical attenuator in silica-on-silicon

We present a novel wide band VOA with low PDL. Our device is a symmetric MZI-based PLC component that uses y-junctions and adiabatic couplers. We describe a model that explains PDL for this VOA and enables polarization control.

Solution of the vector wave equation by the separable effective adiabatic basis set method

A novel separable effective adiabatic basis (SEAB) for the solution of the transverse vector wave equation by the variational method is presented. The basis is constructed by a suitably modified adiabatic approximation. The method of SEAB construction is applicable to the waveguides of a general cross section. By calculating scalar modes in rectangular and rib waveguides, we show that the use of SEAB entails computational effort several orders of magnitude less than the use of the more conventional Fourier basis. As an illustrative example, the polarized modes of a rib waveguide are calculated.

Controlled mode interaction based wide-band and robust optical switching unit in silica-on-silicon

We present a novel wide band and robust planar lightwave circuit (PLC) switching unit having two switching states with low cross talk. The CMI based SU does not require post fabrication trimming and can be used as a normally dark VOA.

Optical switching based on the adiabatic temperature induced mode localization

We present optical switching device that combines two ideas: thermally induced waveguides and adiabatic mode transition in a slowly widening taper. We explain conditions for the optimal operation and present experimental results for 1 /spl times/ 2 switch.

Integrated Optical Switch, Variable Attenuator and Power Monitor Tap Chip for 40-channel PLC ROADM

We present design and performance details of an integrated optical switch, attenuator and tap chip based on adiabatic mode multiplexer for 40-channel PLC ROADM. Our approach enables higher than 48 dB switch shut-off attenuation and isolation.

Degree-expandable colorless, directionless, and contentionless ROADM without drop-side EDFAs

By using an N×M multicast switch, where N is expandable from 4 to ≥16, and M is 16, we experimentally demonstrate that in a metro optical network with OSNR ≥17dB, the sensitivity of an intradyne coherent receiver can reach <; -34dBm for 28Gbaud DP-QPSK signals, thereby enabling a CDC ROADM with on drop-side EDFAs.

Tunable gain tilt compensator using adiabatic mode multiplexing

We built gain tilt compensator in silica on silicon using adiabatic mode multiplexer and y-branch based Mach-Zehnder interferometer. Process and design tolerant building blocks allow flexibility in achieving required response, either normally bright or tilted, and excellent optical performance.

Tapping light from waveguides by high-order mode excitation and demultiplexing

A novel high-performance optical tap with low wavelength-dependent loss(WDL), polarization-dependent loss (PDL), and excess loss is described. The tap is based on exciting a high-order mode by an abrupt change in the waveguide profile, and then tapping the optical power in the high-order mode by using a modal-demultiplexer. The tap can be designed to give a tapping ratio in the range of -30 to -10 dB over a wavelength range of 1510-1640 nm. In addition, it is shown that the tapping ratio is tolerant to process variations, repeatable and predictable, enabling the design to be implemented in a single process run, with no need for additional fine-tuning iterations, while achieving a high process yield. We show that measurements are in good agreement with simulated results. In the tap channel we measured 0.3 dB WDL and 0.2-dB PDL over the C- and L- bands, while the signal in the main channel was virtually uncontaminated relative to a plain single-mode reference waveguide.