A waveguide structure for use in a balanced push-pull Mach Zehnder modulator. The waveguide structure comprises a plurality of layers. The layers comprise, in order: an insulating or semi-insulating substrate; an lower cladding layer; an waveguide core layer; and an upper cladding layer. The lower cladding layer, waveguide core layer, and upper cladding layer are etched to form: a signal waveguide and a ground waveguide, which are connected via the lower cladding layer; and a signal line and a ground line, each located adjacent to the respective waveguide, and each connected to the respective waveguide via one or more respective resistive structures connected in the plane of the lower cladding layer.

An apparatus includes a lithium niobate (LN) layer, and a planar electro-optical modulator having at least one hybrid optical core segment formed of a portion of the LN layer and an optical guiding rib. The optical guiding rib may be located in a top silicon layer of a silicon photonics (SiP) chip, to which a thin-film LN chip is flip-chip mounted, and may be coupled to optical waveguide cores in a first silicon core layer of the SiP chip. One or more drive electrodes are disposed between a substrate of the SiP chip and the LN layer. In some embodiments hybrid optical core segments may include silicon nitride core segments and may form an MZM configured to be differentially or dual-differentially driven.

A push-pull device (10) comprises: a first waveguide (W1) arranged between its first and second electrode (S11, S12) and a second waveguide (W2) arranged between its first and a second electrode (S21, S22). Electrically conductive structures (T11, T12, T21, T22) extend away from one or more of the electrodes (S11, S12, S21, S22) for electrically connecting at least two of the electrodes (S11, S12, S21, S22). The waveguides (W1, W2) and the electrodes (S11, S12, S21, S22) originate from a pre-fabrication process. The waveguides (W1, W2) are poled by a poling (P) originating from a poling process. The electrically conductive structures (T11, T12, T21, T22) originating: from the pre-fabrication process, wherein one or more of the electrically conductive structures (T11, T12, T21, T22) extend to one or more electrically non-conductive gaps (G1, G2), and wherein the device (10) further comprises one or more electrically conductive elements (C1, C2) for electrically connecting two of the electrodes (S11, S12, S21, S22), the electrically conductive elements (C1, C2) being related to the electrically non-conductive gaps (G1, G2) and originating from a post-fabrication process; and/or from a post-fabrication process.

A segmented optical modulator includes two optical modulator segments located along a main face of a photonic chip, and two RF transmission lines connected to drive a corresponding one of the two optical modulator segments. A signal electrode of one of the transmission lines includes a segment that is vertically capacitively coupled to a plurality of spaced ground-connected metallic elements disposed in sequence along a length of the segment above or below thereof so as to be capacitively coupled thereto.

An optical modulator circuit includes first and second electrodes, first and second p-n junction segments (PNJSs), and first and second optical waveguides. The first PNJS includes a first modulating p-n junction (MPNJ) in series with a first non-modulating device (NMD) that are connected to the first and second electrodes, respectively, where the first NMD includes a first substantially larger capacitance than the first MPNJ. The second PNJS includes a second NMD in series with a second MPNJ that are connected to the first and second electrodes, respectively, where the second NMD includes a second substantially larger capacitance than the second MPNJ. The first and second optical waveguides superimpose the first and second MPNJs, respectively, where the first and second MPNJs are configured to modulate a refractive index of the first and second optical waveguides, respectively, based on the substantially larger capacitance of the first NMD and the second NMD.

A circuit that allows the control of a parameter in each arm of a Mach-Zehnder interferometer or modulator in push-pull mode using a single control terminal and a ground (or a differential driving circuit). The parameter that is controlled can be a phase shift, a modulation or an attenuation. The magnitude and the frequency of the parameter can be adjusted.

Provided is a technique for enabling an α parameter to be approximated to zero. A multiple quantum well structure includes a layer structure including a first barrier layer, an intermediate layer, a well layer, and a second barrier layer. The conduction band energies of the first and second barrier layers, the intermediate layer, and the well layer are larger in this order, and the valence band energies of the intermediate layer, the well layer, and the first and second barrier layers are larger in this order.

Disclosed herein is a traveling-wave Mach-Zehnder modulator and method of operating same that advantageously exhibits a reduced optical insertion loss as compared with contemporary Mach-Zehnder structures. Such advantage comes at the modest expense of increased modulator length and increased RF loss.

A waveguide structure for use in a balanced push-pull Mach Zehnder modulator. The waveguide structure comprises a plurality of layers. The layers comprise, in order: an insulating or semi-insulating substrate; an lower cladding layer; an waveguide core layer; and an upper cladding layer. The lower cladding layer, waveguide core layer, and upper cladding layer are etched to form: a signal waveguide and a ground waveguide, which are connected via the lower cladding layer; and a signal line and a ground line, each located adjacent to the respective waveguide, and each connected to the respective waveguide via one or more respective resistive structures connected in the plane of the lower cladding layer.

A method and apparatus for driving an optical push-pull Mach-Zehnder modulator.