Abstract:
The present invention is a tunable optic fiber bandpass filter using flexural acoustic waves that includes an optic fiber; a first silica horn; a first acoustic transducer; a first signal generator; a first acoustic absorber; a core blocker; a second acoustic absorber; a second silica horn; a second acoustic transducer; and a second signal generator. The method of the present invention is receiving an optic signal in a core of an optic fiber; inducing a first flexural acoustic wave in the optic fiber where there is no buffer coating; absorbing the first flexural acoustic wave after it has traveled a distance down the optic fiber; causing user-definable wavelengths of the optic signal to exit the core and enter the cladding of the optic fiber; blocking wavelengths of the optic signal that remain in the core of the optic fiber; inducing a second flexural acoustic wave in the optic fiber where there is no buffer coating; absorbing the second flexural acoustic wave after it has traveled a distance down the optic fiber; and causing user-definable wavelengths of the optic signal to exit the cladding and enter the core of the optic fiber. One signal generator may be used to induce both flexural acoustic waves. In an alternate embodiment, one absorber may be used.
Abstract:
Passive, self-adjusting and tracking optical wavelength filters are described. The filters are absorptive and can be of either transmissive or reflective type. The filters comprise an unpumped doped optical waveguide configured so that signals of different wavelength are spatially decoupled to some extent. The self-adjustment of the filter centre wavelength is achieved by the combined effects of the power-dependent saturable absorption, provided by an appropriate dopant, and partial longitudinal hole burning provided by the spatial decoupling of the different wavelengths. External cavity lasers using this type of filter in the external cavity are also described. This external cavity configuration can provide stable single frequency operation of, for example, a semiconductor laser. By using a saturable absorber for the external cavity (e.g. an erbium doped fibre), longitudinal mode-hopping can be suppressed, ensuring single frequency operation.
Abstract:
A photoacoustic and ultrasonic endoscope includes an optical fiber, a light diffuser configured to radially diffuse a laser beam transmitted through the optical fiber, and an array transducer having a cylindrical shape and surrounding the light diffuser, the array transducer being configured to transmit the diffused laser beam therethrough and to generate an ultrasonic wave or detect an ultrasonic wave generated by an object to be examined.
Abstract:
A wavelength conversion device that converts input signal light having a first frequency into output signal light having a second frequency, includes: a control-light generator that outputs first continuous oscillation light and second continuous oscillation light; and a nonlinear optical medium that cross-phase modulates the input signal light with the first continuous oscillation light and the second continuous oscillation light and generates the output signal light, wherein the control-light generator outputs the first continuous oscillation light and the second continuous oscillation light to have polarized waves in directions orthogonal to each other and have a frequency interval equal to a difference between the first frequency and the second frequency and controls, based on intensity of the output signal light, timings of modulation of phases of the first continuous oscillation light and the second continuous oscillation light to be aligned with each other.
Abstract:
An integrated optical beam steering device includes a planar dielectric lens that collimates beams from different inputs in different directions within the lens plane. It also includes an output coupler, such as a grating or photonic crystal, that guides the collimated beams in different directions out of the lens plane. A switch matrix controls which input port is illuminated and hence the in-plane propagation direction of the collimated beam. And a tunable light source changes the wavelength to control the angle at which the collimated beam leaves the plane of the substrate. The device is very efficient, in part because the input port (and thus in-plane propagation direction) can be changed by actuating only log2 N of the N switches in the switch matrix. It can also be much simpler, smaller, and cheaper because it needs fewer control lines than a conventional optical phased array with the same resolution.
Abstract:
A supercontinuum optical pulse source provides a combined supercontinuum. The supercontinuum optical pulse source comprises one or more seed pulse sources, and first and second optical amplifiers arranged along first and second respective optical paths. The first and second optical amplifiers are configured to amplify one or more optical signals generated by said one or more seed pulse sources. The supercontinuum optical pulse source further comprises a first microstructured light-guiding member arranged along the first optical path and configured to generate supercontinuum light responsive to an optical signal propagating along said first optical path, and a second microstructured light-guiding member arranged along the second optical path and configured to generate supercontinuum light responsive to an optical signal propagating along said second optical path. The supercontinuum optical pulse source further comprises a supercontinuum-combining member to combine supercontinuum generated in at least the first and second microstructured light-guiding members to form a combined supercontinuum. The supercontinuum-combining member comprises an output fiber, wherein the output fiber comprises a silica-based multimode optical fiber supporting a plurality of spatial modes at one or more wavelengths of the combined supercontinuum.
Abstract:
Embodiments of the present invention generally relate to optical mode conversion by nonlinear effects. More specifically, embodiments of the present invention relate to nonlinear mode conversion utilizing intermodal four-wave mixing to convert light between modes having different wavelengths for complex applications. In one embodiment of the present invention, a fiber comprises an input end for receiving light in a first mode at a first wavelength, and an output end for outputting light in a desired second mode at a desired second wavelength, wherein the first wavelength and the second wavelength are not the same. In many embodiments, the fiber comprises a higher-order mode fiber.
Abstract:
A supercontinuum optical source comprises a laser source apparatus comprising at least one laser, the laser source apparatus configured for providing first and second signals; a modulator apparatus downstream of at least one laser of the laser source apparatus for modulating at least one of the first and second signals, the modulator apparatus including at least one modulator; a combiner downstream of the modulator apparatus for combining the first and second signals; an amplifier downstream of the combiner for amplifying the first and second signals after combination; a nonlinear element downstream of the amplifier for receiving the first and second signals after amplification, the nonlinear optical element providing spectral broadening responsive to the first signal and wherein the second signal does not substantially contribute to spectral broadening; and an output for outputting spectrally broadened light from the optical supercontinuum source.
Abstract:
An all-fiber isolator as an optical isolator comprises: an optical fiber acting as an optical light guide for propagating incident light; and a Faraday rotator for rotating by 45° a plane of polarization polarized by the polarizer. The all-fiber isolator exhibits a magneto-optic effect enough to be used as an optical isolator at a visible light wavelength by including quantum dots in a core layer and/or an internal cladding layer of the optical fiber.
Abstract:
A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces metalized with first metallic layers formed thereon, and encapsulated with a dielectric encapsulation material such as for example epoxy. The first metallic layers are exposed through the encapsulation via encapsulation concavities which have a known contour profile, such as a Rogowski edge profile. Second metallic layers are then formed to line the concavities and come in contact with the first metal layer, to form profiled and metalized encapsulation concavities which mitigate enhancement points at the edges of electrodes matingly seated in the concavities. One or more optical waveguides may also be bonded to the substrate for coupling light into the photo-conductive wafer, with the encapsulation also encapsulating the waveguides.