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Curved Lithium Niobate Modulator

IP.com Disclosure Number: IPCOM000022682D
Publication Date: 2004-Mar-25
Document File: 3 page(s) / 109K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a lithium niobate Mach-Zehnder Interferometer (MZI)-based modulator; this modulator is similar to other Mach-Zehnder devices, however it uses curved or bent waveguides instead of straight waveguides. Benefits include the ability to fit easily into a smaller or differently-shaped transponder.

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Curved Lithium Niobate Modulator

Disclosed is a method that uses a lithium niobate Mach-Zehnder Interferometer (MZI)-based modulator; this modulator is similar to other Mach-Zehnder devices, however it uses curved or bent waveguides instead of straight waveguides. Benefits include the ability to fit easily into a smaller or differently-shaped transponder.

Background

Current state-of-the-art modulators are linear, requiring a “longer” space within a transponder.

Figure 3 shows the interior of a lithium niobate MZI. Waveguides are written into lithium niobate to form the two arms of the interferometer. Metal tracks are deposited on top of the waveguide to allow an electric field to be applied. The field can either be in the plane of the material or through the material, depending upon whether x- or z-cut lithium niobate material is used.

General Description

Figures 4, 5 and 6 show the MZI in various bent configurations. When the lengths of the arms are unequal, an extra “kink” is used to equalize the lengths. An alternative approach is to change the dopant concentrations in one arm relative to the other (to change the refractive index), thereby changing the optical path length in one of the arms relative to the other.

Although Figures 7a and 7b occupy identical length, the path length in Figure 7a is approximately 36 times the length shown in Figure 7b. This means that the size of the device can be dramatically reduced and a lower drive voltage can be employed. Managin...