Abstract: The invention relates to an external optical modulator comprising a Mach-Zehnder having a signal electrode including at least four sections of unequal length to one another positioned over an alternating domain structure in an electrooptic substrate, and including a center section, or center pair of sections disposed asymmetrically between pairs surrounding sections. The surrounding pairs, comprise the two sections adjacent the center section or pair of sections, and each two sections adjacent the previous pair of sections, moving outwardly from the center to the final outermost pair, L1 and LN at the RF input 2 and RF output 4. In each pair, the section lengths are equal, or the section closer to the RF output 4 has a longer length than the section closer to the RF input 2. The surrounding pairs have lengths that decrease from the innermost pair to the outermost pair. For a zero chirp structure, the section lengths are selected to maintain an equivalent length for the inverted and uninverted domain sections.

Abstract: The invention relates to a wafer scale process for the manufacture of optical waveguide devices, and particularly for the manufacture of ridge waveguide devices, and the improved waveguides made thereby. The present invention has found a process for achieving sub-micron control of an optical waveguiding layer thickness by providing a dimensionally stable wafer assembly into which adhesive can be introduced without altering the planar relationship between a carrier wafer and an optically transmissive wafer in wafer scale manufacture. This process permits wafer scale manufacture of optical waveguide devices including thin optically transmissive layers. A pattern of spacer pedestals is created by a deposition and etch back, or by a surface etch process to precisely reference surface information from a master surface to a carrier wafer to a thin optically transmissive wafer. The tolerance achievable in accordance with this process provides consistent yield across the wafer.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by electro-migration, galvanic, and other effects that can be present in non-hermetic packages. The RF electrodes are supported by a first surface of the electro-optic substrate, while the bias electrodes are supported by a second opposite surface.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The bias electrodes are at least partially separated from the substrate with a buffer layer, which in one embodiment has a small amount of conductivity. This conductive buffer layer reduces optical loss from the bias electrodes and also reduces DC drift.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by electro-migration and other effects that can be present in non-hermetic packages. The bias electrodes include an upper split portion and an optically transparent lower portion. The optically transparent lower layer improves modulation frequency and reduces optical loss.

Abstract: The invention relates to a wafer scale process for the manufacture of optical waveguide devices, and particularly for the manufacture of ridge waveguide devices, and the improved waveguides made thereby. The present invention has found a process for achieving sub-micron control of an optical waveguiding layer thickness by providing a dimensionally stable wafer assembly into which adhesive can be introduced without altering the planar relationship between a carrier wafer and an optically transmissive wafer in wafer scale manufacture. This process permits wafer scale manufacture of optical waveguide devices including thin optically transmissive layers. A pattern of spacer pedestals is created by a deposition and etch back, or by a surface etch process to precisely reference surface information from a master surface to a carrier wafer to a thin optically transmissive wafer. The tolerance achievable in accordance with this process provides consistent yield across the wafer.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by electro-migration, galvanic, and other effects that can be present in non-hermetic packages. The RF electrodes are supported by a first surface of the electro-optic substrate, while the bias electrodes are supported by a second opposite surface.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The buried bias electrodes are also advantageous in controlling charge build-up with consequent improvement in drift characteristics. The bias electrode material is useful for routing bias signals inside the device, in particular to external terminals, as well as forming encapsulating layers to permit operation in non-hermetic environments, thereby lowering manufacturing costs. Embodiments using both X-cut and Z-cut lithium niobate (LiNbO3) are presented. For the latter, the bias electrodes can be split along their axis to avoid optical losses.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The buried bias electrodes are also advantageous in controlling charge build-up with consequent improvement in drift characteristics. The bias electrode material is useful for routing bias signals inside the device, in particular to external terminals, as well as forming encapsulating layers to permit operation in non-hermetic environments, thereby lowering manufacturing costs. Embodiments using both X-cut and Z-cut lithium niobate (LiNbO3) are presented. For the latter, the bias electrodes can be split along their axis to avoid optical losses.

Abstract: The invention relates to an electro-optic directional coupler suitable for use as a variable optical attenuator at reduced voltages compared to those known in the prior art. The present invention has found that by careful selection of an asymmetric directional coupler geometry, the transfer function of the device can be shifted so that it has an operating point between maximum and minimum transmission. Signal electrodes driven in push pull configuration advantageously use this operating point to achieve significant reduction in operating voltages for switching to maximum or minimum transmission. Asymmetry is created in the directional coupler by forming the waveguides to have different propagation constants by a difference in waveguide width, depth, index of refraction or index profile.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The buried bias electrodes are also advantageous in controlling charge build-up with consequent improvement in drift characteristics. The bias electrode material is useful for routing bias signals inside the device, in particular to external terminals, as well as forming encapsulating layers to permit operation in non-hermetic environments, thereby lowering manufacturing costs. Embodiments using both X-cut and Z-cut lithium niobate (LiNbO3) are presented.

Abstract: An optical external modulator includes an optical waveguide having a first interferometer section and a second interferometer section formed on an electro-optic substrate. An electrode structure disposed on the substrate transmits an RF drive signal that is applied to the first and second interferometer sections in series. A reflector optically coupled to the substrate redirects light away from the first interferometer section to the second interferometer section and provides an optical fold region that introduces an optical time delay between the first and second interferometer sections. The optical time delay is used for at least partially compensating for a velocity mismatch between the light and the RF drive signal.

Abstract: An optical modulator which has substantially low loss and has an improvement in voltage reduction is disclosed having an electro-optic lithium niobate substrate. The substrate has first, second and third ridges extending along its surface. Extending along the first and second ridges are first and second waveguides. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. A second section of the slotted extends parallel to and adjacent to the first section on the third ridge. In summary, this invention provides a slotted ground electrode wherein a slot is formed in the substrate between the slotted electrode.

Abstract: An optical modulator which has substantially low loss and has an improvement in voltage reduction is disclosed having an electro-optic lithium niobate substrate. The substrate has first, second and third ridges extending along its surface. Extending along the first and second ridges are first and second waveguides. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. A second section of the slotted extends parallel to and adjacent to the first section on the third ridge. In summary, this invention provides a slotted ground electrode wherein a slot is formed in the substrate between the slotted electrode.

Abstract: An optical external modulator includes an optical waveguide having a first interferometer section and a second interferometer section formed on an electro-optic substrate. An electrode structure disposed on the substrate transmits an RF drive signal that is applied to the first and second interferometer sections in series. A reflector optically coupled to the substrate redirects light away from the first interferometer section to the second interferometer section and provides an optical fold region that introduces an optical time delay between the first and second interferometer sections. The optical time delay is used for at least partially compensating for a velocity mismatch between the light and the RF drive signal.

Abstract: The invention relates to an electro-optic modulator structure containing an additional set of bias electrodes buried within the device for applying bias to set the operating point. Thus the RF electrodes used to modulate incoming optical signals can be operated with zero DC bias, reducing electrode corrosion by galvanic and other effects that can be present in non-hermetic packages. The buried bias electrodes are also advantageous in controlling charge build-up with consequent improvement in drift characteristics. The bias electrode material is useful for routing bias signals inside the device, in particular to external terminals, as well as forming encapsulating layers to permit operation in non-hermetic environments, thereby lowering manufacturing costs. Embodiments using both X-cut and Z-cut lithium niobate (LiNbO3) are presented.

Abstract: An optical digital external modulator having a cascaded arrangement of interferometers is provided. The optical modulator includes an electrode structure for applying an electric field to each interferometer in the cascade and biasing circuitry coupled to the electrode structure for biasing each interferometer at a predetermined bias point. In particular, each predetermined bias point is selected to be above quadrature and for providing improved transmission performance of digital data signals. Preferably, the modulator has a reflective design that helps to increase the modulation bandwidth, lower the drive voltage, and reduce size.

Abstract: The invention relates to suppression of high frequency resonance in an electro-optical device. The electro-optical device includes an optical waveguide formed in a substrate and a plurality of electrically floating electrode segments that are positioned on the substrate to intensify an electric field in the optical waveguide. The device also includes a RF ground electrode that is positioned on the substrate. The RF ground electrode defines a slot having a shape that suppresses modal conversion and propagation of high order modes in the RF ground electrode and in the plurality of electrically floating electrode segments, thereby suppressing modal coupling to the substrate. The device further includes a buffer layer formed on the upper surface of the substrate, on the plurality of electrically floating electrode segments, and in the slot. A driving electrode receives a RF signal that induces-the electric field in the optical waveguide.

Abstract: A co-planar waveguide interferometric electro-optic modulator is disclosed. A Z-cut lithium niobate electro-optic substrate includes a first and second waveguide that are formed in the lithium niobate electro-optic substrate. An elongate RF electrode at least partially covers one of the waveguides. A slotted electrode is disclosed formed by two elongate substantially-parallel electrodes one of which is at least partially covers the other of the waveguides. At least one electrode is substantially greater, preferably at least twice the width of the elongate RF electrode.

Abstract: An optical digital external modulator having a cascaded arrangement of interferometers is provided. The optical modulator includes an electrode structure for applying an electric field to each interferometer in the cascade and biasing circuitry coupled to the electrode structure for biasing each interferometer at a predetermined bias point. In particular, each predetermined bias point is selected to be above quadrature and for providing improved transmission performance of digital data signals. Preferably, the modulator has a reflective design that helps to increase the modulation bandwidth, lower the drive voltage, and reduce size.