Thanh Trung Le

The design of multimode interference couplers with arbitrary power splitting ratios on an SOI platform

A method for obtaining variable power splitting ratios using multimode interference couplers is presented. The method relies on etching the surface on either the top of the MMI coupler or on the linking waveguides. Devices have been designed for the silicon on insulator (SOI) platform. The 3D beam propagation method (3D-BPM) and the full-vectorial finite difference method (FV-FDM) are used to verify the working principle of the devices and to evaluate performance.

The design of signal processing devices employing SOI MMI couplers

There is currently considerable research interest in all-optical signal processing for telecommunication applications. In this paper it is shown that a range of all-optical signal processing functions may be carried out using passive waveguides and phase-shifting elements as basic building blocks. Two types of multimode interference (MMI) photonic circuits, based on silicon-on-insulator (SOI) technology, are discussed in detail. In the first type, phase-shifting elements are added to the ports of MMI couplers. In the second type, the waveguide structure of the MMI coupler itself is modified to achieve a range of signal processing functions. Designs are verified using 2D and 3D simulations.

The modeling of MMI structures for signal processing applications

Microring resonators are promising candidates for photonic signal processing applications. However, almost all resonators that have been reported so far use directional couplers or 2×2 multimode interference (MMI) couplers as the coupling element between the ring and the bus waveguides. In this paper, instead of using 2×2 couplers, novel structures for microring resonators based on 3×3 MMI couplers are proposed. The characteristics of the device are derived using the modal propagation method. The device parameters are optimized by using numerical methods. Optical switches and filters using Silicon on Insulator (SOI) then have been designed and analyzed. This device can become a new basic component for further applications in optical signal processing. The paper concludes with some further examples of photonic signal processing circuits based on MMI couplers.

Optical signal processing using MMI elements

In the past, multimode interference (MMI) devices mostly have been used as couplers, combiners and simple switches. Recently, there has been much research interest in making modifications to the basic MMI structure in order to achieve much greater functionality. Of particular interest has been the possibility of implementing a variety of all-optical signal processing functions. This paper reviews recent novel advances with these devices and examines some of the possible signal processing applications.

Photonic Signal Processing Using MMI Coupler-Based Microring Resonators

Some novel configurations for microring resonators, based on MMI couplers, that are suitable for photonic signal processing applications. A number of relevant design issues are discussed. As an example, a microring resonator based on 3x3 MMI couplers has been designed; simulation results show that such a device has the potential advantages of high performance and size reduction.

A Novel Proposal for Low Power Optical Switches Based on Microring Resonators

A new optical switch based on microring resonators (MRs) is proposed in this paper. By using the thermo-optic effect or electro-optic effect, the switching can be easily obtained at a very low switching power. The design, analysis and performance considerations of the proposed switch are given in detail.

MMI Devices for Photonic Signal Processing

Low order MMI (multimode interference) devices are now being employed as integrated components of photonic filter circuits such as ring resonators. This paper examines further possible applications of MMI devices in photonic signal processing.

A novel tunable wavelength selective reflector based on microring resonators

In this paper, we propose a novel tunable wavelength selective reflector for planar lightwave circuits based on microring resonators. The desired characteristics of the reflector can be obtained by using thermal-optic or electro-optic effects.

Improved effective index method for designing devices based on silicon nano-waveguides

A new effective index method for designing devices including directional couplers based on silicon nano-waveguides is proposed in this paper. The optimal value of the refractive index of the device in two dimensional model is determined and optimized. The results are checked with 3D numerical methods.

Analysis and Design of Optical Reflectors Based on a Series of Ring Resonators

In this paper, a design approach of optical reflectors based on multiple ring resonators is presented. The analysis and design are based on the scattering matrix method and it can be applied to a structure for the optical reflector with any number of ring resonators. The effect of transmission losses inside the rings on the spectral performance of optical reflectors based on ring resonators is highlighted.