An optical phase modulator comprises a cascaded array of optical resonators, wherein each of the optical resonators has an input port and an output port. A plurality of waveguides are coupled between the optical resonators and are configured to provide cascaded optical communication between the optical resonators. Each of the waveguides is respectively coupled between the output port of one optical resonator and the input port of an adjacent optical resonator. A transmission electrode is positioned adjacent to the optical resonators, with the transmission electrode configured to apply a drive voltage across the optical resonators. The optical phase modulator is operative to co-propagate an input optical wave with the drive voltage, such that a resonator-to-resonator optical delay is matched with a resonator-to-resonator electrical delay.

The present disclosure describes an optical waveguide provided with an incident side reflection film and an emission side reflection film to resonate light incident via the incident side reflection film and formed to penetrate from the incident side reflection film to the emission side reflection film for propagating resonated light. The disclosure also includes a substrate to which the optical waveguide is formed from a top surface thereof and a first protection member and a second protection member formed with a material corresponding to a material of the substrate, wherein the first protection member and the second protection member are arranged on the optical waveguide such that one end facet of the first protection member forms an identical plane with a first end facet of the substrate including an optical incident end.

A high-power electro-optic modulator (EOM) is formed to use specialized electrodes of a material selected to have a CTE that matches the CTE of the modulator's crystal. Providing CTE matching reduces the presence of stress-induced birefringence, which is known to cause unwanted modulation of the propagating optical signal. The specialized electrodes are preferably formed of a CuW metal matrix composite having a W/Cu ratio selected to create the matching CTE value. Advantageously, the CuW-based electrodes also exhibit a thermal conductivity about an order of magnitude greater than conventional electrode material (brass, Kovar) and thus provide additional thermal stability to the EOM's performance.

The optical modulator includes an optical modulation element having a first optical waveguide, a second optical waveguide, a first electrode which applies an electric field to the first optical waveguide, and a second electrode which applies an electric field to the second optical waveguide, and a control unit configured to control an applied voltage between the first electrode and the second electrode. When a half-wave voltage of the optical modulation element is Vπ and a null point voltage of the optical modulation element is Vn, the control unit sets an operating point Vd in a range of Vn+0.50Vπ≤Vd≤Vn+0.75Vπ or Vn−0.75Vπ≤Vd≤Vn−0.50Vπ and sets an applied voltage width Vpp, which is an amplitude of an applied voltage applied to the optical modulation element, in a range of 0.22Vπ≤Vpp≤0.50Vπ.

An electro-optic modulator includes an optical structure and an electrical structure. The optical structure includes an input waveguide, a beam splitter, a first waveguide arm, a second waveguide arm, a beam combiner, and an output waveguide; each of the first waveguide arm and the second waveguide arm includes a conventional waveguide region. The first waveguide arm further includes a first modulating region, a second modulating region, and a third modulating region. The second waveguide arm further includes a fourth modulating region, a fifth modulating region, and a sixth modulating region; the electrical structure includes a traveling wave electrode including a signal-ground-signal electrode structure. The traveling wave electrode further includes a signal input region, a modulating electrode region, and a matched resistor region. The modulating electrode region includes a first signal electrode, a ground electrode, and a second signal electrode.

A reflective spatial light modulator includes an electro-optic crystal having an input surface to which input light is input and a rear surface opposing the input surface, a light input/output unit being disposed on the input surface of the electro-optic crystal and having a first electrode through which the input light is transmitted, a light reflection unit including a substrate including a plurality of second electrodes and an adhesive layer for fixing the substrate to the rear surface and being disposed on the rear surface of the electro-optic crystal, and a drive circuit applying an electric field between the first electrode and the plurality of second electrodes.

An optical waveguide device includes a substrate on which an intermediate layer, a thin-film LN layer of lithium niobate, and a buffer layer are stacked; an optical waveguide formed in the thin-film LN layer; and a plurality of electrodes near the optical waveguide. The intermediate layer and the buffer layer contain a same material of a metal element of any one of group 3 of group 18 of a periodic table of elements.

An optical waveguide device has a substrate, an intermediate layer, a thin-film LN layer containing an X-cut lithium niobate, and a buffer layer stacked on the substrate, and an optical waveguide having a ridge shape formed in the thin-film LN layer. The optical waveguide device includes a plurality of electrodes provided, respectively, at a first side and a second side of the optical waveguide. The electrodes are disposed so that respective bottom surfaces thereof are at positions lower than a position of a surface of the buffer layer.

A laser apparatus includes at least one electro-optic (EO) medium through which a polarized laser beam passes for N times, forming a plurality of first-pass to Nth-pass beams, by reflecting the polarized laser beam from at least one reflection mirror, and a power supplier configured to alternately provide a 1/N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to the EO medium, λ being a wavelength of the polarized laser beam. The at least one EO medium is tilted at angle θ and/or angle di with respect to one of the plurality of first-pass to Nth-pass beams. The at least one EO medium comprises a M number of EO mediums, and the power supplier is configured to alternately provide a 1/M*N of a half-wave (λ/2) or quarter-wave (λ/4) voltage and remove the voltage to each of the M number of EO mediums.

A light shielding member of the present invention includes a first polarizing plate, a second polarizing plate facing the first polarizing plate, and a thermosensitive sheet interposed between the first polarizing plate and the second polarizing plate, in which the first polarizing plate and the second polarizing plate are positioned so that their respective transmission axes are different from each other, and the thermosensitive sheet contains a side chain crystal polymer that crystallizes at a temperature lower than the melting point and exhibits fluidity at a temperature of the melting point or higher. The light shielding member may transmit light at a temperature lower than the melting point and may not transmit light at a temperature of the melting point or higher, when light travels from one of the first polarizing plate and the second polarizing plate toward the other.