Provided is a technique for reducing, using a simple circuit configuration, an amplitude difference between electric signals that are input to respective optical waveguide arms. An optical modulator includes: an optical demultiplexer that splits continuous wave light as received; first and second optical waveguide arms through which the continuous wave light as split propagates; an optical phase n shifter that introduces a phase shift of π to the continuous wave light as split; an optical multiplexer combines the continuous wave light propagating through the first and second optical waveguide arms; first and second signal electrodes that respectively input the electric signals to the first and second optical waveguide arms; a junction capacitance connected in shunt to at least one of the first and second signal electrodes; and a DC voltage source that applies a DC voltage to the junction capacitance.

The purpose of the present invention is to make it possible to output stable light by optimizing the wavelength conversion efficiency in a wavelength conversion element without employing an optical detection device such as a photo diode in a laser light source device. A fundamental light wave emitted from a semiconductor laser (2) is wavelength converted by a wavelength conversion element (5) and is emitted therefrom. A lighting circuit (20) supplies electric power for the aforementioned semiconductor laser (2) to turn on the semiconductor laser (2). A control unit (21) controls the operation of the device while controlling the amount of power supplied to a heater means (7) such that the wavelength conversion element (5) reaches a temperature at which optimum wavelength conversion efficiency is acquired. The temperature detected by a temperature detection means (Th1) is input to the control unit (21), and the control unit (21) defines the temperature of the wavelength conversion element (5) at which the maximum amount of power is supplied to the heater means (7) as a set temperature at which the optimum wavelength conversion efficiency is acquired, and performs feedback control of the temperature of the wavelength conversion element (5) so that the temperature of the wavelength conversion element (5) reaches the aforementioned set temperature by controlling the amount of heat supplied from the heater means (7).

The optical device includes an optical modulator positioned on a base. The modulator includes a ridge extending upward from the base. The ridge includes an electro-absorption medium through which light signals are guided. A thermal conductor is positioned so as to conduct thermal energy away from the ridge. The distance between the thermal conductor and the ridge changes along a length of at least a portion of the ridge.

An optoelectronic device, including: a rib waveguide, the rib waveguide including: a ridge portion, which includes a temperature-sensitive optically active region, and a slab portion, positioned adjacent to the ridge portion; the device further comprising a heater, disposed on top of the slab portion wherein a part of the heater closest to ridge portion is at least 2 μm away from the ridge portion. The device may also have a heater provided with a bottom cladding layer, and may also include various thermal insulation enhancing cavities.

A device, includes: a ring waveguide; a diode comprising a junction extending at least partly in the ring waveguide; and a first circuit configured to supply a signal representative of a leakage current in the diode.

An optical modulator includes: a substrate; a waveguide layer including first and second optical waveguides formed of an electro-optic material film on the substrate to have a ridge shape and to be disposed adjacent to each other; an RF part that applies a modulated signal to the optical waveguides; and a DC part that applies a DC bias to the optical waveguides. The DC part includes: a buffer layer covering at least upper surfaces of the optical waveguides; a first bias electrode opposed to the first optical waveguide through the buffer layer; and a second bias electrode provided adjacent to the first bias electrode. A first DC bias voltage is applied between the first and second bias electrodes. A waveguide layer removal area in which at least part of the waveguide layer is removed is provided at least under an area between the first and second bias electrodes.

Disclosed is a liquid crystal film for a vehicle, including a first electrode, a liquid crystal molecular layer provided on the first electrode, and a second electrode provided on the liquid crystal molecular layer. The liquid crystal molecular layer includes a pre-polymer, a liquid crystal material, and a crosslinking agent.

Embodiments herein relate to techniques for baseline wander (BLW) compensation. The technique may include identifying a data stream that is to be modulated by a ring modulator of an optical transmitter, wherein the data stream has a frequency operable to cause thermal-based BLW of an optical output of the optical transmitter. The technique may further include adjusting a time-varying direct current (DC) voltage bias of the ring modulator based on the frequency of the data stream. Other embodiments may be described and/or claimed.

To provide an optical element in which an electrode is directly formed on an LN substrate, and a drift phenomenon is suppressed. In an optical element including: a substrate made of lithium niobate crystals; and an electrode disposed on the substrate, the substrate and the electrode are in direct contact with each other, and as a contact metal disposed on a surface of the electrode where the electrode is in contact with the substrate, a metal material whose standard enthalpy of formation per coordinate bond upon oxidation is greater than a standard enthalpy of formation per coordinate bond of niobium pentoxide is used.

An optoelectronic device, including: a rib waveguide, the rib waveguide including: a ridge portion, which includes a temperature-sensitive optically active region, and a slab portion, positioned adjacent to the ridge portion; the device further comprising a heater, disposed on top of the slab portion wherein a part of the heater closest to ridge portion is at least 2 μm away from the ridge portion. The device may also have a heater provided with a bottom cladding layer, and may also include various thermal insulation enhancing cavities.