A wavemeter fabricated using integrated optics technology. A waveguide structure is formed in a substrate, the structure including signal and reference waveguides and means for coupling an optical input signal into both waveguides. Means are provided for varying the optical path length of the signal waveguide with respect to the reference waveguide in response to a control signal. Optical signals passing through the waveguides are coupled to a detection system that produces a feedback signal having a characteristic that is a function of the optical path length difference between the waveguides, and of the wavelength of the optical input signal. A control system receives the feedback signal and produces the control signal such that the feedback signal characteristic is driven towards a predetermined value. The control signal then provides a measure of the wavelength of the optical input signal.
An improved integrated optic interferometric sensor uses a planar waveguide to offer detection sensitivity equal to the Mach-Zehnder interferometric sensor, while retaining the input coupling and manufacturing ease characteristic of a planar waveguide. Enhanced output signal processing capabilities are provided by use of at least two integrated optic interferometric sensors employing planar constructs.
The invention relates to an electric field sensor useful in detecting and measuring wideband transient electrical responses by means of an integrated optical waveguide interferometer. Mach-Zehnder devices are produced wherein one waveguide channel has been reverse poled, or has domain inversion, preferably by means of titanium diffusion into said waveguide channel. Also produced is an electrode-less optical interferometer modulator by which an optical output signal is modulated at the same frequency as an applied electric field.
An optical sensor (100) that measures gas concentration (121) includes a light input port (103), and a light output port (111). A reference waveguide (105) and a measurement waveguide (113) are both coupled between the light input port (103) and the light output port (111). The measurement waveguide (113) preferably includes a hydrocarbon-catalytic material (114). When light (101) is injected into the light input port (103), the light traverses to the light output port (111) via both waveguides (105,113). Preferably, the hydrocarbon-catalytic material (114) in the measurement waveguide (113) will react with certain hydrocarbons present in an engine's exhaust gas stream (121) and heat will be generated in the measurement waveguide (113). This heat generation will change a refractive index and optical path length of the measurement waveguide (113) compared to the reference waveguide (105). A detector (117) detects light present at the light output port (111) which will have an intensity dependent on a difference between the refractive index and optical path length of the measurement waveguide (113) and the reference waveguide (105).
A waveguide optical device having a guide member for propagation of light in a longitudinal direction. The guide member has upper and lower boundaries. A mass of birefringent material is disposed proximal to the guide member. The birefringent material has molecular dipoles subject to alignment by an imposed electrical field. The birefringent mass is overlapped by the optical field of the propagated light. An upper electrode is disposed in spaced relation to the birefringent mass. A lower electrode is disposed in spaced relation to the guide member. The electrodes have the capability of imposing an alternating current voltage across the birefringent mass to rotate the molecular dipoles of the birefringent mass in a plane defined by the normal to the guide member and the propagation vector of the light. The boundaries and the electrodes define an upper isolation zone between the upper electrode and the upper boundary, a guide path between the boundaries, and a lower isolation zone between the lower boundary and the lower electrode. The guide path has an effective index of refraction greater than the effective indexes of refraction of the isolation zones.
