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.

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 photonic integrated circuit device includes a semiconductor substrate (e.g., wafer) having a chip region therein, which is bounded on at least one side thereof by a scribe line. The chip region includes an optical transmitter, an optical receiver and a test optical waveguide. This test optical waveguide is coupled to the optical transmitter and the optical receiver and overlaps the scribe line. During a substrate dicing operation, a portion of the test optical waveguide overlapping the scribe line is removed.

A monolithic integrated electro-optical phase modulator, a Mach-Zehnder modulator including one or more of the phase modulators, and method for fabricating the phase modulator by III-V-on-silicon semiconductor processing are provided. The phase modulator includes a silicon-based n-type substrate base layer, and a III-V n-type ridge waveguide for propagating light, wherein the ridge waveguide protrudes from and extends along the n-type substrate base layer. Further, the phase modulator includes one or more insulating layers provided on the ridge waveguide, wherein the one or more insulating layers have together a thickness of 1-100 nm, and a silicon-based p-type top cover layer provided on the one or more insulating layers at least above the ridge waveguide.

An optical phase modulator includes a lower cladding layer, a core formed on the lower cladding layer, an upper cladding layer formed over the core, and a heater. In addition, the optical phase modulator includes a semiconductor layer which is embedded in the upper cladding layer, is disposed above the core, and is formed of a compound semiconductor, and the heater is constituted by an impurity introduction region formed in the semiconductor 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.

Various embodiments of the present disclosure are directed towards an integrated chip including a waveguide and a heater structure. The waveguide is disposed on a substrate and comprises an active region that extends continuously along a first distance. The heater structure overlies the waveguide. The heater structure comprises a conductive structure over the active region and a vertical structure disposed between the conductive structure and the substrate. The vertical structure comprises a conductive upper vertical segment and a lower vertical segment. The conductive structure and the conductive upper vertical segment continuously laterally extend across a second distance that is greater than or equal to the first distance. The first distance is greater than a width of the conductive structure.

Provided is an optical phase shifter. The optical phase shifter includes: a slab waveguide in which a first slab region doped into a first conductivity type and a second slab region doped into a second conductivity type are arranged side by side to form a PN junction; and a rib waveguide disposed on the slab waveguide such that one side of the rib waveguide makes contact with the first slab region, and an opposite side of the rib waveguide makes contact with the second slab region, wherein the rib waveguide includes first to third rib waveguide layers that are sequentially stacked, the first and third rib waveguide layers include silicon (Si), and the second rib waveguide layer includes silicon-germanium (SiGe).

Embodiments are disclosed for generating an optical Pulse Amplitude Modulation 4-level (PAM-4) signal from bandwidth-limited duobinary electrical signals in a Mach-Zehnder modulator. An example system includes an MZM structure that comprises a first waveguide interferometer arm structure associated with a first semiconductor device and a second waveguide interferometer arm structure associated with a second semiconductor device. A polybinary electrical signal is applied to or between the first semiconductor device and the second semiconductor device to convert an input optical signal provided to the MZM structure into an optical PAM-4 signal.

A laminate (22) is formed on a semiconductor substrate (10). Two or more grooves (54) are formed in the laminate (22). A mesa (24) with two grooves among the two or more grooves (54) positioned on both sides is formed. An insulating resin film (30) is embedded into the two or more grooves (54). A first opening (32) is formed at the insulating resin film (30) embedded in one of the two or more grooves (54) and an electrode (46) extracted upward from a bottom surface (36) is formed. A first side surface (34) of the insulating resin film (30) is inclined in a forward tapered direction.