This paper presents a proposal for a novel integrated tun-able coupler device called programmable coupler ladder, based on Titanium diffused lithium niobate waveguide and Y-junction reflector. Unlike the traditional serial to parallel converter, the coupler ladder sorts the output bits in the time axis using a built-in delay waveguide. With a proper control signal it can perform signal processi...

A 120o optical hybrid based on 3x3 multimode interference coupler is reported. The device exhibits less than 10o phase deviation over 55 nm in the Cand L-band. Keywords—120-degree hybrid; multimode interference coupler;

Optical nanoantennas can be used for coupling radiation to or from waveguides in analogy to micro- and radio-wave systems. In this letter we provide a systematic description of the design approaches for a coupler to a plasmonic slot waveguide in the telecom range around 1.55 µm with realistic excitation from a lensed optical fiber. We show that the best coupling efficiency of 26% can be achieve...

A polarization-independent optical directional coupler based on slot waveguides is proposed and analyzed by using rigorous full-vectorial analysis methods based on a finite-element scheme. Properly choosing materials and structural parameters makes the coupling length for quasi-TE modes become equal to that for quasi-TM modes. Tolerances to operating wavelength and structural parameters are als...

An optical add-drop multiplexer with a gratingloaded directional coupler in silica waveguides is demonstrated. The device for this configuration has a large fabrication tolerance and is small in size. A new scheme, in which the coupling length of the directional coupler is twice the complete coupling length, enables low cross-talk for both add and drop operations. This device is polarization-in...

Morphology-dependent resonances (MDR’s) of polystyrene microspheres were excited by an optical fiber coupler. For optical elimination of the air–cladding interface at the optical fiber coupler surface, the microsphere was immersed in an index-matching oil. MDR’s were observed, even though the relative refractive index between the microsphere and the oil was only 1.09. The observed MDR spectra a...

in this paper a novel design of all-optical half-subtractor based on nonlinear directional coupler is proposed. by using four waveguides and appropriately adjusting the refractive indices and selecting the proper length of waveguides, halfsubtractor function can be obtained. the operation of this function is simulated by rsoft cad-layout (beamprop) simulator. the simulation results confirm the ...

We propose and demonstrate an efficient coupler for compact mode conversion between a fiber and a submicrometer waveguide. The coupler is composed of high-index-contrast materials and is based on a short taper with a nanometer-sized tip. We show that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective inde...

A polarization-selective holographic optical element with compact dimensions of 2.4mm X 1mm X 1mm (width X length X thickness) is proposed. The element includes three modules: a holographic polarizing beam-splitter, a holographic input coupler, and a dove-prism coupler so that a simple and dense optical pick-up head can be achieved. Polarization properties of holographic volume gratings are bri...

An all-fiber-ring resonator has been constructed using a single strand of single-mode optical fiber and a directional coupler. Derivation of the resonator finesse in terms of fiber and directional coupler parameters is given. A finesse of 80 has been achieved experimentally. Applications of such a fiber-ring resonator are discussed.