In photonic integrated circuits implemented in silicon-on-insulator substrates, non-conductive channels formed, in accordance with various embodiments, in the silicon device layer and/or the silicon handle of the substrate in regions underneath radio-frequency transmission lines of photonic devices can provide breaks in parasitic conductive layers of the substrate, thereby reducing radio-frequency substrate losses.

An electro-optic device 200 comprising a substrate in which first and second waveguides 202, 203 are formed. The device also comprises first and second electrodes 204, 205 comprising an optically transparent conductive material and including primary portions 204a, 205a overlying the first and second waveguides 202, 203 for electrically biasing the first and second waveguides. The device is configured such that one of the first and second electrodes includes one other portion 204b, 205b arranged alongside the primary portion 204a, 205a of the other of the first and second electrodes. This arrangement improves the electro-optic efficiency of the device without the need for a buffer layer in the electrodes.

Semiconductor electro-optical modulators which receives an input optical signal and provides a modulated output optical signal based on an input electrical signal are disclosed. The semiconductor electro-optical modulator may comprise at least one electrical transmission line adapted to carry the input electrical signal and a semiconductor electro-optical phase shifter waveguide electrically coupled to the at least one electrical transmission line. An optical path length of the semiconductor electro-optical phase shifter waveguide between a modulation begin plane of the semiconductor electro-optical modulator and a modulation end plane of the semiconductor electro-optical modulator may be greater than an electrical path length of the electrical transmission line between the modulation begin plane of the semiconductor electro-optical modulator and the modulation end plane of the semiconductor electro-optical modulator.

An optical modulator includes a plurality of Mach-Zehnder optical modulation units. Each of the plurality of Mach-Zehnder optical modulation units include a pair of first signal wirings, a pair of first ground wirings, a pair of first signal electrode pads, and a pair of first ground electrode pads. The pair of first ground electrode pads is displaced by less than the first interval from the pair of first signal electrode pads so as to separate from a center line of each of the plurality of Mach-Zehnder optical modulation units.

An optical Mach Zehnder modulator is described. The optical Mach Zehnder modulator may comprise a plurality of segments separated by curved waveguides. For example, an optical Mach Zehnder modulator may comprise a first waveguide arm having a first pn-junction formed therein, a second waveguide arm having a second pn-junction formed therein, a third waveguide arm coupled to the first waveguide arm via a first curved waveguide and a fourth waveguide arm coupled to the second waveguide arm via a second curved waveguide. The segments may have the same polarities. Alternatively, the segments may have opposite polarities. The different segments may be driven using different RF signals. The RF signals may be delayed from one another.

A semiconductor Mach-Zehnder optical modulator includes input side lead-out lines, phase modulation electrode lines, output side lead-out lines, electrodes that apply modulation signals propagating through the phase modulation electrode lines to respective waveguides, and ground lines. Furthermore, at least one n-type semiconductor layer or p-type semiconductor layer is formed between a substrate and a dielectric layer in a lower layer under the output side lead-out lines intermittently along the output side lead-out lines.

Provided is an optical waveguide element including a first interactive part, a first EO substrate line, a second interactive part, and a second EO substrate line. A relay substrate unit includes a first relay substrate line, a second relay substrate line, and a loss adjusting part. The loss adjusting part is provided to the relay substrate line in a combination in which an electrical loss is low so that an electrical loss in a combination of the first EO substrate line and the first relay substrate line, and an electrical loss in a combination of the second EO substrate line and the second relay substrate line become approximately the same as each other.

An aspect of the present invention is an optical modulator including a substrate, a plurality of optical waveguides, and a plurality of modulation electrodes provided on the substrate in order to modulate light propagating through the optical waveguides. The modulation electrodes include signal electrodes, to which modulation signals are supplied, and ground electrodes. The signal electrodes include first and second signal electrodes. The ground electrodes include a first ground electrode provided between the first and second signal electrodes, a second ground electrode provided on the opposite side of the first signal electrode from the first ground electrode adjacent to the first signal electrode, and a third ground electrode provided on the opposite side of the second signal electrode from the first ground electrode adjacent to the second signal electrode. A concave groove is formed in each of the first to third ground electrodes.

An electro-optic modulator includes a Mach-Zehnder interferometer having a bias input, an optical input, and an optical output. A first arm comprises an optical waveguide. A second arm comprises an optical waveguide. A plurality of electrode segments is distributed along or proximate to a length of the optical waveguides of the first and second arms. A plurality of amplifiers, where at least one of the plurality of amplifiers has an RF input that receives an electrical modulation signal, and where each of the plurality of amplifiers are electrically connected to one of the plurality of electrode segments so as to provide distributed gain. A number of the plurality of amplifiers is chosen to achieve a desired combination of noise figure and spur-free dynamic range.

A novel electro-optic optical modulator device and a related method for creating the novel optical modulator device are disclosed. In one embodiment, the novel optical modulator comprises a high index contrast optical waveguide, a mesa region, electrical modulation electrodes, RF transmission lines, and interconnection layers. The high index contrast optical waveguide comprises an electro-optic slab core region and a high index ridge core region. A mesa section which includes the core regions can be formed, and electrical modulation electrodes are placed on etched sidewalls of the mesa section to achieve electro-optical index modulation of the electro-optic slab core region. The RF transmission lines include RF electrodes that connected to the electrical modulation electrodes. The interconnection layers connect the modulation electrodes with the RF electrodes by using etched vias. The novel optical modulator can also incorporate foldable modulation arms for poling in the electro-optic slab core region.