Provided is an optical element including: a main body which is formed of a medium capable of transmitting first light and second light having a wavelength longer than that of the first light, in which the main body includes an incident region into which the first light and the second light are incident, in which a gap which is inclined with respect to the incident region and in which a medium having a refractive index with respect to the first light and the second light lower than that of the main body is disposed is provided inside the main body, and in which a gap width from an interface bordering the main body and the gap is larger than a penetration length of an evanescent wave of the first light at the interface and is smaller than a penetration length of an evanescent wave of the second light at the interface.

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.

An integrated optical device includes a substrate. A waveguide includes a lithium niobate. A TiO.sub.2 coating is disposed at least in part over a longitudinal surface of the waveguide as a coated waveguide supported by the substrate. A silicon oxide substantially can cover and surround the waveguide in cross section over a longitudinal direction of said waveguide as an optical cladding. A method for substantially eliminating optical damage in lithium niobate devices is also described.

In order to provide an optical modulator capable of preventing damage to the substrate and preventing deterioration of the properties of the modulator by reducing the stress on the substrate generated by the modulation electrode, there is provided an optical modulator 1, including: a substrate 5 having an electro-optic effect; an optical waveguide 10 formed on the substrate 5; and a modulation electrode (signal electrode S and ground electrode G) provided on the substrate 5 and modulating a light wave propagating in the optical waveguide 10, wherein a resin 8 to reduce the stress on the substrate 5 generated by the modulation electrode is arranged between a part of the bottom surface of the modulation electrode and the substrate 5 facing a part of the bottom surface of the modulation electrode.

Provided is an optical waveguide element that prevents damage to a substrate and improves productivity. In an optical waveguide element in which an optical waveguide (24, 23) is formed on a substrate 1, a groove portion 3 is formed in at least a part of the substrate along an outer periphery 10 of the substrate 1.

According to the present invention, a pulsed laser output section outputs a laser beam having a predetermined wavelength as first pulses. An optical path determining section receives the first pulses and determines one or more among two or more optical paths for each of the first pulses for output. A wavelength changing section receives light beams travelling, respectively, through the two or more optical paths and, when the power of the traveling light beams exceeds a threshold value, changes the light beams to have their respective different wavelengths for output. A multiplexer multiplexes outputs from the wavelength changing section. The optical path determining section allows for change in the power ratio between a first power of the light beam traveling through one of two among the two or more optical paths and a second power of the light beam traveling through the other of the two optical paths.

In order to provide an optical waveguide element that is capable of reducing coupling loss at a coupling portion with an optical fiber and of reducing propagation loss in an optical waveguide, the optical waveguide element comprises a supporting substrate and a waveguide layer consisting of a material having an electro-optic effect stacked on the supporting substrate, wherein a rib portion for forming an optical waveguide is provided protruding on an upper surface of the waveguide layer; a groove portion is formed on an upper surface of the supporting substrate directly below a part of the rib portion; and the groove portion is filled with a material having an effective refractive index comparable to that of the waveguide layer.

An electro-holographic light field generator device is disclosed. The light field generator device has an optical substrate with a waveguide face and an exit face. One or more surface acoustic wave (SAW) optical modulator devices are included within each light field generator device. The SAW devices each include a light input, a waveguide, and a SAW transducer, all configured for guided mode confinement of input light within the waveguide. A leaky mode deflection of a portion of the waveguided light, or diffractive light, impinges upon the exit face. Multiple output optics at the exit face are configured for developing from each of the output optics a radiated exit light from the diffracted light for at least one of the waveguides. An RF controller is configured to control the SAW devices to develop the radiated exit light as a three-dimensional output light field with horizontal parallax and compatible with observer vertical motion.

Disclosed is a device for interaction between a laser beam and a hyperfine energy transition of a chemical species. The device further includes an electro-optic modulator with a single sideband with an input optical waveguide suitable for receiving a source laser beam and an output optical waveguide suitable for generating an output laser beam and an electronic system suitable for generating and applying, simultaneously, a first modulated electrical signal, sin(Ω.sub.1t)) to a first hyperfrequency pulse on a first high-frequency electrode of the electro-optic modulator and, respectively, another modulated electrical signal, cos(Ω.sub.1t)) to the first pulse on another high-frequency electrode of the electro-optic modulator, in such a way as to frequency-switch the output laser beam to a first optical frequency offset from the first pulse with respect to the initial optical frequency.

A wavelength converter for LiDAR systems, such as automotive LiDAR, is disclosed. Implementation of the wavelength converter in LiDAR systems makes possible generation and modulation of laser light in the silicon response region, conversion of the laser light to an eye-safe wavelength for emission and reflection from a target, and efficient conversion of the wavelength of the laser light to the silicon response region. The wavelength converter may implement a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. The wavelength conversion design also has the potential for vehicle-to-vehicle (V2V) communication to enable a combined LiDAR and V2V communication system.