Improved dither detection, measurement, and voltage bias adjustments for an electro-optical modulator are described. The electro-optical modulator generally includes RF electrodes and phase heaters interfaced with semi-conductor waveguides on the arms of Mach-Zehnder interferometers, where a processor is connected to output a bias tuning voltage to the electro-optical modulator for controlling optical modulation. A variable gain amplifier (VGA) can be configured with AC coupling connected to receive a signal from a transimpediance amplifier (TIA) that is configured to amply a photodetector signal from an optical tap that is used to measure an optical signal with a dither signal. The analog to digital converter (ADC) can be connected to receive output from the VGA. The processor can be connected to receive the signal from the ADC and to output the bias tuning voltage based on evaluation of the signal from the tap.

An optical modulator includes a plurality of optical modulation units having a Mach-Zehnder type optical waveguide consisting of two optical waveguides and a high-frequency line pair arranged along the two optical waveguides and consisting of two signal electrodes for applying a pair of differential high-frequency signals, and a plurality of high-resistance conductive films are provided between adjacent high-frequency line pairs separated from the high-frequency line pair.

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 electro-optical modulator is provided. The modulator comprises a first and a second optical waveguide, at least one first capacitance, via which a voltage can be applied to a light-guiding region of the first optical waveguide, at least one second capacitance, via which a voltage can be applied to a light-guiding region of the second optical waveguide, an electrically conductive region, via which the first and second capacitances are electrically connected to one another, and a feed line to the electrically conductive region, via which feed line a DC voltage can be applied to the electrically conductive region, wherein the feed line is constituted such that it represents an electrical resistance connected in parallel with the second capacitance, and a compensation resistance connected in parallel with the first capacitance and serving for reducing transients in a voltage profile on the first and second capacitances during the operation of the modulator.

Apparatus, circuits and methods for reducing mismatch in an electro-optic modulator are described herein. In some embodiments, a described optical includes: a splitter configured for splitting an input optical signal into a first optical signal and a second optical signal; a phase shifter coupled to the splitter; and a combiner coupled to the phase shifter. The phase shifter includes: a first waveguide arm configured for controlling a first phase of the first optical signal to generate a first phase-controlled optical signal, and a second waveguide arm configured for controlling a second phase of the second optical signal to generate a second phase-controlled optical signal. Each of the first and second waveguide arms includes: a plurality of straight segments and a plurality of curved segments. The combiner is configured for combining the first and second phase-controlled optical signals to generate an output optical signal.

Provided is a method for manufacturing an optical component, including the following steps: producing at least one optical waveguide or a part of an optical waveguide on a substrate, where producing the optical waveguide or the part of the optical waveguide includes producing a waveguide core or a portion of a waveguide core, and where the waveguide core or the portion of the waveguide core includes silicon nitride, a polymer or a III-V semiconductor material; and arranging at least one layer of lithium niobate on a side of the waveguide core or of the portion of the waveguide core facing away from the substrate. After arranging at least one layer of lithium niobate at least one of the following steps is carried out: structuring at least one layer of lithium niobate, producing a further portion of the waveguide core and/or arranging at least one contact structure for electrically contacting the at least one layer of lithium niobate.

The optical modulator includes an optical modulation element having a first optical waveguide, a second optical waveguide, a first electrode which applies an electric field to the first optical waveguide, and a second electrode which applies an electric field to the second optical waveguide, and a control unit configured to control an applied voltage between the first electrode and the second electrode. When a half-wave voltage of the optical modulation element is Vπ and a null point voltage of the optical modulation element is Vn, the control unit sets an operating point Vd in a range of Vn+0.50Vπ≤Vd≤Vn+0.75Vπ or Vn−0.75Vπ≤Vd≤Vn−0.50Vπ and sets an applied voltage width Vpp, which is an amplitude of an applied voltage applied to the optical modulation element, in a range of 0.22Vπ≤Vpp≤0.50Vπ.

An electro-optic modulator includes an optical structure and an electrical structure. The optical structure includes an input waveguide, a beam splitter, a first waveguide arm, a second waveguide arm, a beam combiner, and an output waveguide; each of the first waveguide arm and the second waveguide arm includes a conventional waveguide region. The first waveguide arm further includes a first modulating region, a second modulating region, and a third modulating region. The second waveguide arm further includes a fourth modulating region, a fifth modulating region, and a sixth modulating region; the electrical structure includes a traveling wave electrode including a signal-ground-signal electrode structure. The traveling wave electrode further includes a signal input region, a modulating electrode region, and a matched resistor region. The modulating electrode region includes a first signal electrode, a ground electrode, and a second signal electrode.

An optical waveguide structure forms an MZI in proximity to an electro-optic material. A first (second) electrical input port is configured to receive a first (second) drive signal. The second drive signal has a negative amplitude relative to the first drive signal. A first (second) transmission line is configured to propagate a first (second) electromagnetic wave over at least a portion of a first (second) optical waveguide arm to apply an optical phase modulation. A drive signal interconnection structure is configured to provide a first electrical connection between the first electrical input port and an electrode shared by the transmission lines, and a second electrical connection between the second electrical input port and respective electrodes of the transmission lines; and is configured to preserve relative phase shifts between the drive signals. Input impedances at the first and second electrical input ports are substantially equal to each other.

A compact optical device, such as an optical transmitter or transceiver, including a folded configuration, where an optical signal generated by a laser source propagates in a first direction, then is redirected in an orthogonal direction, and then redirected again to propagate in a second direction opposite the first direction. In accordance with the folded configuration, the optical signal from the laser source is coupled to a Mach-Zehnder interferometer (MZI) modulator that includes a thin-film lithium niobate (TFLN) waveguide coupled to a radio frequency (RF) transmission line to produce an RF signal modulated optical signal for remote transmission.