A semiconductor device include: a first bus waveguide; a first silicon ring optically coupled to the first bus waveguide; a backup silicon ring optically coupled to the first bus waveguide; a first heater and a second heater configured to heat the first silicon ring and the backup silicon ring, respectively; and a first switch, where the first switch is configured to electrically couple the first silicon ring to a first radio frequency (RF) circuit when the first switch is at a first switching position, and is configured to electrically couple the backup silicon ring to the first RF circuit when the first switch is at a second switching position.

Methods and apparatuses for downconverting are provided. A dual-drive mach zehnder modulator (DDMZM) receives: a continuous wavelength optical signal, an input signal (microwave signal), and local oscillator tones. The DDMZM includes: first and second arms formed from optical waveguides which receive the optical signal, a first modulator that receives the input signal, and a second modulator that receives the oscillator tones. The input signal is modulated onto the optical signal propagating through the first arm to form a first modulated optical signal. The oscillator tones and third-order intermodulation products of those tones are modulated onto the optical signal propagating through the second arm to form a second modulated optical signal. The modulated optical signals are combined to form an output optical signal. The oscillator tones are spaced two folded bandwidths apart and centered within a spectrum of interest of the input signal.

Various embodiments of a coplanar waveguide (CPW) transmission line as well as a silicon-based electro-optic (E-O) modulator comprising the CPW transmission line are described. The CPW transmission line has a curved or winding shape. The silicon-based E-O modulator includes a rib optical waveguide, a beam splitter, a beam combiner, and a CPW transmission line that exhibits the winding shape. At least one of the two optical arms of the rib optical waveguide alternately and periodically extends through a first groove and a second groove of the CPW transmission line. The plurality of active sections of the rib optical waveguide are evenly distributed on both sides of the CPW transmission line to suppress undesired transmission modes. An increased length of transmission path of the rib optical waveguide is also avoided or minimized, thereby reducing the transmission speed mismatch of the E-O modulator, which is essential for achieving high-speed operation.

A first transmission line comprises a first pair of electrodes receiving an electrical drive comprising first and second drive signals, which are loaded by a first series of p-n junctions applying optical phase modulation to respective optical waves propagating over a first section of the first and second optical waveguide arms of an MZI. A second transmission line comprises a second pair of electrodes configured to receive the electrical drive after an electrical signal delay. The second pair of electrodes are loaded by a second series of p-n junctions applying optical phase modulation to the respective optical waves propagating over a second section of the first and second optical waveguide arms after propagation over the first section. An electrode extension structure provides the electrical drive to the second pair of electrodes, and comprises an unloaded transmission line portion imposing the electrical signal delay based on an optical signal delay.

Optical modulators are described having a Mach-Zehnder interferometer and a pair of RF electrodes interfaced with the Mach-Zehnder interferometer in which the Mach-Zehnder interferometer comprises optical waveguides formed from semiconductor material. The optical modulator additionally comprises a plurality of phase shifters configured to interface with the plurality of interconnected optical waveguides such that at least one phase shifter of the plurality of phase shifters is interfaced with at least one optical waveguide of the plurality of interconnected optical waveguides. A phase shifter controller, including an energy source with a variable output controlled by the controller and a plurality of electrical connections connecting the energy source to each of the plurality of phase shifters, is also included. In various embodiments, the plurality of electrical connections are configured to provide approximately equal power to each of the phase shifting elements from the energy source.

An optical waveguide device includes a slot groove formed in a substrate; a pair of electrodes disposed in the slot groove; an electro-optic polymer material in the slot groove; and a step portion formed at an outer side of the slot groove, in a length direction of the slot groove.

A multi-section optical modulator and related method are disclosed wherein two waveguide arms traverse a plurality of successive modulating sections. A differential drive signal is applied separately to each waveguide arm of each modulating sections in synchronism with the transmission of light along the waveguide arms, effecting a dual differential driving of each section. By suitably selecting the number of modulating sections and the section length, a high modulation bandwidth and a high modulation efficiency may be achieved simultaneously for a given peak-to-peak voltage swing of the drive signal.

A velocity mismatch between optical signals and microwave electrical signals in electro-optic devices, such as modulators, may be compensated by utilizing different lengths of bends in the optical waveguides as compared to the microwave electrodes to match the velocity of the microwave signal propagating along the coplanar waveguide to the velocity of the optical signal. To ensure the electrode bends do not affect the light in the optical waveguide bends, the electrode may have to be rerouted, e.g. above or below, the optical waveguide layer. To ensure that the pair of optical waveguides have the same optical length, a waveguide crossing may be used to cross the first waveguide through the second waveguide.

Provided is an IQ optical modulator including a nest-type MZ optical waveguide having optical modulation regions of I channel and Q channel End portions of an input optical waveguide and an output optical waveguide of the IQ optical modulator are located on a same edge face of a chip of the IQ optical modulator, an optical cross waveguide is included in which an optical waveguide between a first optical combiner and a second optical combiner of the nest-type MZ optical waveguide and the input optical waveguide cross each other, a first optical divider is provided between the I-channel optical modulation region and the Q-channel optical modulation region, and a light propagation direction in the first optical divider and a light propagation direction in the optical modulation regions are opposite to each other.

An optical transmitter comprises a directly coupled MZ interferometer and driver circuit. The MZ interferometer comprises a pair of differentially driven MZ electrodes configured to impart RF signals to light travelling through respective arms of the interferometer, and to receive DC bias as a positive voltage via lower n-type cladding of the MZ interferometer. The lower n-type cladding is at a different positive DC potential to an upper plane RF ground of the MZ interferometer, but the lower n-type cladding and the upper plane RF ground have similar AC potential. The MZ interferometer also comprises a pair of resistors in series configured to provide differential RF termination of the MZ electrodes; and a capacitive coupling between a virtual ground formed at a centre point between the pair of resistors and an RF ground configured to provide common-mode RF termination. The DC supply for the driver circuit is applied to the centre point of the RF termination.