Abstract: First and second waveguide structures are coupled to a waveguide coupling structure, the first waveguide structure comprising a first guiding core structure formed on a first cladding structure, and a second cladding structure formed on the first guiding core structure. The first and second waveguide structures have respective guiding ridges. The second waveguide structure comprises a second guiding core structure formed on a third cladding structure, and a fourth cladding structure formed on the second guiding core structure. The waveguide coupling structure comprises a transition structure, a multimode interference structure between the transition structure and the second waveguide structure, and an electrode over at least a portion of the guiding ridge within the second cladding structure and over at least a portion of the transition structure.

Abstract: First and second waveguide structures are coupled to a waveguide coupling structure, the first waveguide structure comprising a first guiding core structure formed on a first cladding structure, and a second cladding structure formed on the first guiding core structure. The first and second waveguide structures have respective guiding ridges. The second waveguide structure comprises a second guiding core structure formed on a third cladding structure, and a fourth cladding structure formed on the second guiding core structure. The waveguide coupling structure comprises a transition structure, a multimode interference structure between the transition structure and the second waveguide structure, and an electrode over at least a portion of the guiding ridge within the second cladding structure and over at least a portion of the transition structure.

Abstract: A photonic integrated circuit including a photonic device and a gain element, said gain element formed by a process including: depositing by epitaxy a first doped layer onto a substrate; depositing by epitaxy an active layer capable of optical gain onto the first doped layer; depositing by epitaxy a second doped layer onto the active layer; pattern etching at least the second doped layer and the active layer to form a first ridge; and depositing by epitaxy a current blocking layer laterally adjacent to the first ridge at least partially filling the volume of active layer that was removed by the pattern etching; wherein the current blocking layer forms a portion of the photonic device.

Abstract: A method includes obtaining a semiconductor wafer having an orientation in a plane; depositing one or more masks to a semiconductor wafer, wherein each mask is configured to cover a portion of the semiconductor wafer, and wherein each mask includes a perimeter having multiple sides that are substantially aligned along a preferred crystal direction relative to the orientation that provides reduced or enhanced growth enhancement at edges of the substantially aligned sides; and performing Selective Area Epitaxy (SAE) growth on a surface of the semiconductor wafer, wherein the one or more masks inhibit the SAE growth over the associated portion.

Abstract: A photonic integrated circuit including a photonic device and a gain element, said gain element formed by a process including: depositing by epitaxy a first doped layer onto a substrate; depositing by epitaxy an active layer capable of optical gain onto the first doped layer; depositing by epitaxy a second doped layer onto the active layer; pattern etching at least the second doped layer and the active layer to form a first ridge; and depositing by epitaxy a current blocking layer laterally adjacent to the first ridge at least partially filling the volume of active layer that was removed by the pattern etching; wherein the current blocking layer forms a portion of the photonic device.

Abstract: A method includes obtaining a Photonic Integrated Circuit (PIC) with a butt-joint between a first core and a second core, wherein the butt-joint includes a poor quality region, wherein the first core is associated with a first optical device and the second core is associated with a second optical device, and wherein the first optical device and the second optical device are each on the PIC; etching away at least part of the poor quality region to form an etch trench between the first core and the second core; and growing an interconnect core between the first core and the second core in the etch trench.

Abstract: A method for operating an optical system may include selecting a band gap energy level for an optical waveguide in an electro-optic modulator. The band gap energy level may correspond to a predetermined phase shift efficiency of a waveguide electrode coupled to the optical waveguide. The method may further include generating, across a conductive plane in the electro-optic modulator, a differential voltage that produces a predetermined temperature in a waveguide core of the optical waveguide. The predetermined temperature may correspond to the band gap energy level selected for the optical waveguide. The method may further include transmitting, through the optical waveguide and with a modulating voltage applied by the waveguide electrode, an optical wave to an optical wave combiner. The modulating voltage may produce an amount of phase shift in the optical wave at the predetermined phase shift efficiency.

Abstract: A monolithic optoelectronic device has a spot-size converter optically connected to a waveguide. The overclad extending over the core of the waveguide is thinner and differently doped than the overclad of the spot-size converter. This structure can be made by applying a process of etching and enhanced selective area regrowth to create regions of the overclad of different thickness or doping. The spot-size converter core is made of a different material than the waveguide core by using etching and enhanced selective area regrowth.

Abstract: A Mach-Zehnder optical modulator is provide and has a travelling wave electrode extending over two optical waveguide branches and modulating the relative phase of the optical beam components propagating in those branches. The travelling wave electrode has transmission line conductors and pairs of waveguide electrodes, the waveguide electrodes of each pair being coupled to one of the optical waveguide branches, respectively. The travelling wave electrode further includes active devices having a high impedance input electrically connected to one of the transmission line conductors and a low impedance output electrically connected to one of the waveguide electrodes. Each active device transfers the electrical modulation signal from the associated transmission line conductor onto the associated waveguide electrode according to a voltage transfer function.

Abstract: A monolithic optoelectronic device has a spot-size converter optically connected to a waveguide. The overclad extending over the core of the waveguide is thinner and differently doped than the overclad of the spot-size converter. This structure can be made by applying a process of etching and enhanced selective area regrowth to create regions of the overclad of different thickness or doping. The spot-size converter core is made of a different material than the waveguide core by using etching and enhanced selective area regrowth.

Abstract: Mach-Zehnder optical modulators and IQ modulators based on a series push-pull travelling wave electrode are provided. The modulator includes a conductive backplane providing an electrical signal path. One or more voltage control taps are electrically connected to the conductive backplane within an area underneath the travelling wave electrode and provide an equalizing DC control voltage to the conductive backplane. In other variants, a plurality of conductive backplane segments are provided, and at least one voltage control tap is electrically connected to each conductive backplane segment within an area underneath the travelling wave electrode and provides a DC control voltage to the corresponding conductive backplane segment.

Abstract: A monolithic optoelectronic device has a spot-size converter optically connected to a waveguide. The overclad extending over the core of the waveguide is thinner and more highly doped that the overclad of the spot-size converter. This structure can be made by applying a process of selective etching and enhanced regrowth to create selective regions of the overclad of different thickness or doping.

Abstract: Mach-Zehnder optical modulators and IQ modulators based on a series push-pull travelling wave electrode are provided. The modulator includes a conductive backplane providing an electrical signal path. One or more voltage control taps are electrically connected to the conductive backplane within an area underneath the travelling wave electrode and provide an equalizing DC control voltage to the conductive backplane. In other variants, a plurality of conductive backplane segments are provided, and at least one voltage control tap is electrically connected to each conductive backplane segment within an area underneath the travelling wave electrode and provides a DC control voltage to the corresponding conductive backplane segment.

Abstract: A Mach-Zehnder optical modulator with a series push-pull traveling wave electrode uses a balanced coplanar stripline with lateral ground planes. Two signal electrodes extend along the center of the optical modulator adjacent and parallel to the optical waveguides in a series push-pull configuration. The ground planes run parallel to the signal electrodes, but are spaced laterally outward from the signal electrodes.

Abstract: A Mach-Zehnder optical modulator with a travelling wave electrode has a signal transmission line conductor (S) carrying an input electrical signal, and two ground transmission line conductors (G1 and G2) providing a return path for the electrical signal. The signal transmission line conductor is positioned between the first and second ground lines, and the first and second optical waveguide branches are positioned between the signal transmission line conductor and the first ground line. The modulator therefore has a GSG structure providing an asymmetrically-loaded configuration.

Abstract: A Mach-Zehnder optical modulator is provide and has a travelling wave electrode extending over two optical waveguide branches and modulating the relative phase of the optical beam components propagating in those branches. The travelling wave electrode has transmission line conductors and pairs of waveguide electrodes, the waveguide electrodes of each pair being coupled to one of the optical waveguide branches, respectively. The travelling wave electrode further includes active devices having a high impedance input electrically connected to one of the transmission line conductors and a low impedance output electrically connected to one of the waveguide electrodes. Each active device transfers the electrical modulation signal from the associated transmission line conductor onto the associated waveguide electrode according to a voltage transfer function.

Abstract: An electrical waveguide transmission device accepts a differential electrical input signal (e.g., S+ and S?) propagating along two separate signal conductors with grounded electrical return paths, and outputs the differential input signal to a series push-pull traveling wave electrode Mach-Zehnder optical modulator over a pair of output conductors that act as a return path for each other and provide a desired characteristic impedance matching that of the Mach-Zehnder optical modulator.

Abstract: A Mach-Zehnder optical modulator with a travelling wave electrode having one or more signal transmission line conductors and one or more ground transmission line conductors is provided. The modulator includes a ground strip conductor extending substantially in parallel to the ground transmission line conductors, and a distributed bridging structure electrically connecting the ground strip conductor and at least one of the ground transmission line conductors along a substantial portion of a length thereof. The distributed bridging structure may be embodied by a plurality of electrical connections at disposed regularly spaced intervals.

Abstract: A Mach-Zehnder optical modulator with a travelling wave electrode has a signal transmission line conductor (S) carrying an input electrical signal, and two ground transmission line conductors (G1 and G2) providing a return path for the electrical signal. The signal transmission line conductor is positioned between the first and second ground lines, and the first and second optical waveguide branches are positioned between the signal transmission line conductor and the first ground line. The modulator therefore has a GSG structure providing an asymmetrically-loaded configuration.

Abstract: A Mach-Zehnder modulator has an optical splitting element splitting an input optical signal into two optical signals that are conveyed by two optical waveguide arms, and an optical combining element combining the two optical signals into an output optical signal. Two traveling wave electrodes (TWEs) carry an electrical modulation signal to induce a change in phase of these two optical signals, and include a number of pairs of modulation electrodes positioned adjacent to the waveguide arms. At least some of the electrodes in one waveguide arm have a different shape (e.g., length or width) than the electrodes in the other waveguide arm to alter the effectiveness of the electrodes in inducing a phase change in the two optical signals.