An optical modulation control device includes: a photodetector or a photodetector which detects light emitted from a Mach-Zehnder interferometer and outputs an intensity signal indicating intensity of the light; and a phase-bias search unit which searches for and obtains a phase bias when the intensity signal outputted from the photodetector has a local minimum value or a phase bias when the intensity signal outputted from the photodetector has a local maximum value while adjusting a phase bias injected into an optical path inside the Mach-Zehnder interferometer, and records a set of the obtained phase bias and a wavelength of the light.

An optical modulation device includes: a substrate which extends in one direction; an optical waveguide provided on the substrate in a longitudinal direction of the substrate; a half-wave plate; and a combining element which faces an end portion of the substrate and combines two types of linearly polarized light, which have vibration planes orthogonal to each other, to generate composite light, in which the optical waveguide modulates the linearly polarized light which propagates through an inside of the optical waveguide to generate first polarized light and second polarized light, which are linearly polarized light, the half-wave plate is provided at a position to which the second polarized light enters, the combining element includes a transparent base body, a first optical film provided on a first surface of the transparent base body, and a second optical film provided on a second surface which faces the first surface of the transparent base body, the first optical film transmits one of the first polarized light and the second polarized light, which is emitted through the half-wave plate, and reflects the other light, the second optical film reflects the one light, and the composite light is reflected in a direction intersecting the longitudinal direction.

An optical modulator includes a first shifter and a second shifter. The first shifter includes a first waveguide through which first light passes, and a first electrode that causes power according to a drive voltage to act on the first waveguide. The first shifter shifts a phase of the first light passing through the first waveguide in accordance with the drive voltage applied to the first electrode. The second shifter includes a second waveguide through which second light passes, and a second electrode that causes power according to a drive voltage to act on the second waveguide. The second shifter shifts a phase of the second light passing through the second waveguide in accordance with the drive voltage applied to the second electrode. The second shifter is constituted to have a smaller amount of phase shift according to a predetermined amount of drive voltage than the first shifter.

A first directional coupler branching input light into a cross-port path having a branching ratio η and a bar-port path having a branching ratio 1-η. A first arm propagating light from the cross-port path of the first directional coupler; a second arm propagating light from the bar-port path of the first directional coupler. A second directional coupler outputting output light acquired by combining the light being input from the first arm and the light being input from the second arm at the cross-port branching ratio γ and the bar-port branching ratio 1-γ. A phase modulation unit providing a phase difference between the light propagating through the first arm and the light propagating through the second arm. η and 1-η, and γ and 1-γ are determined such that an a parameter being a chirp parameter is a negative value.

An optical voltage prove includes: an optical modulator 1 having two modulation electrodes 11 and 12, the optical modulator 1 being configured to modulate an intensity of an incident light depending on a voltage between the two modulation electrodes and output the incident light which is modulated; an input/output optical fiber 2 connected with the optical modulator 1; two contact terminal attachment portions 5, 6 to which contact terminals 3, 4 can be detachably attached and contacted, the two contact terminals 3, 4 being configured to be in contact with the points to be measured, the two contact terminal attachment portions 5, 6 being respectively connected with the modulation electrodes 11, 12; and a package 8 that houses the optical modulator 1 and a part of the input/output optical fiber 2. A voltage signal induced via the contact terminals 3, 4 is converted into an optical intensity modulation signal. When an electric wave having a measurement frequency is applied while the contact terminal attachment portions 5, 6 are opened, the package 8 exhibits a shielding effect of attenuating the electric wave by 15 dB or more compared to an output signal intensity measured without providing the package.

To autonomously apply a bias voltage to an optical modulator according to phase angle information provided from outside in a pluggable optical module. A pluggable electric connector (11) can communicate a communication data signal and a control signal with an optical communication apparatus (92). An optical signal output unit (13) includes a Mach-Zehnder type optical modulator including a phase modulation area and outputs an optical modulation signal (LS) modulated according to the communication data signal. An optical power control unit (14) can control optical power of the optical modulation signal (LS). A pluggable optical receptor (15) can output the optical modulation signal (LS) to an optical fiber (91). A control unit (12) controls a modulation operation of the optical signal output unit (13) and the bias voltage applied to the phase modulation area.

The control unit (12) determines the bias voltage applied to the phase modulation area according to phase angle information of the control signal (CON1). The optical signal output unit (13) applies the bias voltage determined by the control unit (12) to the phase modulation area.

Power consumption in MZI-based integrated photonic switches or filters throughout the operational life can be reduced by reducing fabrication-induced phase misalignment between the unpowered operational mode of the switch or filter and the predominant switch state, and/or by enabling low-power compensation for any such misalignment. In various embodiments, misalignment is reduced by increasing the width of the waveguides implementing the interferometer arms of the MZI, and/or by structuring a region containing the MZI symmetrically to diminish stress-induced misalignment. In some embodiments, phase tuners are used to actively compensate for any phase misalignment, with a tuner drive voltage substantially lower than used to switch to the non-dominant state.

The present disclosure relates to a surveying instrument including a chassis, an optical system having an optical axis, a stage attached to the chassis and an optical component. The optical system may be adapted to receive and/or transmit light. The optical component is located at, or in proximity to, the optical axis. The received and/or transmitted light passes through the optical component. The stage includes an actuating member arranged to act on the optical component for movement thereof. The actuating member may be responsive to temperature so as to induce a displacement of the optical component relative to the chassis along the optical axis in response to a temperature change.

To autonomously apply a bias voltage to an optical modulator according to phase angle information provided from outside in a pluggable optical module. A pluggable electric connector (11) can communicate a communication data signal and a control signal with an optical communication apparatus (92). An optical signal output unit (13) includes a Mach-Zehnder type optical modulator including a phase modulation area and outputs an optical modulation signal (LS) modulated according to the communication data signal. An optical power control unit (14) can control optical power of the optical modulation signal (LS). A pluggable optical receptor (15) can output the optical modulation signal (LS) to an optical fiber (91). A control unit (12) controls a modulation operation of the optical signal output unit (13) and the bias voltage applied to the phase modulation area. The control unit (12) determines the bias voltage applied to the phase modulation area according to phase angle information of the control signal (CON1). The optical signal output unit (13) applies the bias voltage determined by the control unit (12) to the phase modulation area.

Power consumption in MZI-based integrated photonic switches or filters throughout the operational life can be reduced by reducing fabrication-induced phase misalignment between the unpowered operational mode of the switch or filter and the predominant switch state, and/or by enabling low-power compensation for any such misalignment. In various embodiments, misalignment is reduced by increasing the width of the waveguides implementing the interferometer arms of the MZI, and/or by structuring a region containing the MZI symmetrically to diminish stress-induced misalignment. In some embodiments, phase tuners are used to actively compensate for any phase misalignment, with a tuner drive voltage substantially lower than used to switch to the non-dominant state.