Abstract: A method for forming a grating in a photosensitive medium such as a photosensitive optical fiber. The method comprises impinging a pair of interfering, actinic beams onto the medium, and during the impinging step, advancing the illuminated portion of the interference pattern relative to the medium. The advancement is carded out without changing the phase, or registration, of the interference pattern. According to one embodiment of the invention, a grating having a spatially dependent period is produced by varying the wavelength or the intersection angle of the actinic beams during the advancement. According to a second embodiment of the invention, a grating having a spatially dependent refractive index perturbation is produced by varying the dose of actinic radiation received by the medium during the advancement.

Abstract: Light from a laser (10) is divided by a beam splitter (12) to provide signal (15) and reference (14) channels. The signal channel light is expanded (11) to illuminate an acousto-optic (AO) device (13). This leads to a spatial distribution of Doppler shifted frequencies. This spatial distribution then illuminates a spatial light modulator (SLM) (19) such that a number of parallel and discrete optical channels (112) emerge. In a local area network (LAN) the optical signal channels are coupled into a single mode optical fibre (22) and then heterodont to the reference laser light from a further optical fibre (23) in an optical coupler (25). In a receiver the modulated light is detected (32) and the detected signal connected to the transducer of an AO device (35). The AO device (35) is illuminated by a receiver laser light (36) and the emerging modulated light is incident on a focal plane detector array (39) where each detector (310) then receives light corresponding to each of the transmitted channels (311).

Abstract: A Bragg grating is made in an optical path composed of material exhibiting change in index when exposed to radiation of an actuating frequency by passing radiation from a source of such actuating frequency through a mask with periodic variation in transmission to expose the material of the path to a diffraction pattern.

Abstract: Disclosed is apparatus for continuous wideband tuning of lasers, along with means for relating such tuning to a reference wavelength, by maintaining any desired offset from that reference wavelength. Also disclosed are multichannel fiber optics communications networks employing the above means, said networks being self organizing in terms of the wavelengths of their channels.

Abstract: An optical device comprising a length of optical waveguide (1) having incorporated therein an extended sequence of coupled single resonator structures (9) so as to form an optical slow wave structure. The sequence of resonator structures is suitably formed by a Bragg diffraction grating pattern (7) extending along the waveguide.

Abstract: A light detector provides wavelength tracking, monitoring or similar function by forming a diffraction grating in a light waveguide. Diffracted light from the waveguide is received by a light detecting device having multiple detecting portions. Changes in the emission angle of the diffracted light caused by the wavelength or other fluctuation of the incident light are detected. The detected information can be used for wavelength tracking by injecting current into or applying a voltage to the waveguide to regulate the Bragg wavelength of the light waveguide, for monitoring and/or controlling the oscillation wavelength of a semiconductor laser or for other purposes.

Abstract: In accordance with the teachings of the present invention, an enhanced performance opto-electric modulator (30 or 70) is provided herein which compensates for phase velocity mismatches between optical modulation and an RF electric signal. The modulator (30) includes an optical waveguide (38, 40) formed in a substrate (32) and coupled to an optical input (56). An RF waveguide (46, 48) is formed on the substrate (32) for applying an electric field (59) to a modulation region (50) adjacent the optical waveguide so as to modulate an optical signal. The substrate (32) has a ferroelectric domain which includes periodically inverted and non-inverted regions (54) and (52) which compensate for phase differences within the modulation region (50). In a preferred embodiment, the optical waveguide includes two substantially parallel optical waveguides (38) and (40) which have outputs combined to provide for an amplitude modulated (AM) optical output signal (60).

Abstract: An integrated electro-optic waveguide device has a substrate, an optically transparent lower buffer layer positioned atop the substrate, an optically transparent nonlinear optic (NLO) organic poled polymer waveguide positioned atop the lower buffer layer, and a GaAs laser diode optically coupled to the waveguide. The NLO material has a higher refractive index than the buffer layer. A ridge waveguide section forms an extended resonator cavity for the laser diode and combines a modulation function and an in-cavity quasi-phase matched second harmonic generation function. A grating coupled ridge-to-planar waveguide section combines a beam expansion function, a TE-TM conversion function, and a beam turning function. A planar surface prism electrode section provides electro-optic waveguide beam deflection. A dual linear grating coupler section performs the output/input coupling. Beam turning is accomplished by a planar waveguide mirror section.

Abstract: An acousto-optic apparatus is described that varies the time delay of electrical signals over a continuum of delays. In the preferred embodiment, a light source, which can be either coherent or incoherent, emits an optical beam that is focused into an acousto-optic cell. An input electrical signal is used to drive the acousto-optic cell which, in turn, modulates the focused optical beam. Portions of the input optical beam are modulated and diffracted at angles proportional to the frequencies and phases contained in the input electrical signal. By appropriately choosing the cone of angles at which the light is focused into the acousto-optic cell, the diffracted optical beam can be made to overlap with portions of the undiffracted, unmodulated optical beam. All of the light exiting the acousto-optic cell is then collected onto a device for detection. Optical photomixing of the diffracted beam and the undiffracted beam is performed in order to derive the input electrical signal with a time delay.

Abstract: An apparatus for changing the direction of an optical beam comprises a thin film grating deflector; an optical energy source for providing optical energy to strike the deflector at a first angle with respect to gratings of the deflector and to exit the deflector at a second angle with respect to the gratings; and elements for applying a voltage to the deflector to vary the second angle. The optical energy source preferably comprises a laser diode; and a collimator for coupling energy from the laser diode to the grating deflector. The grating deflector is a planar waveguide including a plurality of stacked quantum wells formed of GaAs separated by barriers of AlGaAs. Optical energy provided to the grating deflector in a first direction is deflected in a second direction. These directions define a plane in which the waveguide is disposed. The quantum wells are stacked in a direction perpendicular to a plane of the waveguide.

Abstract: A rare-earth doped glass waveguide is optically pumped to produce superfluorescent light. The waveguide is formed in a glass substrate. The pump light is input to a first end of the optical waveguide, and the output is emitted from the other end. A grating formed on the waveguide near the output end reflects the pump light to separate the pump light from the output light.

Abstract: An optical modulator includes a substrate, a first waveguide layer formed on the substrate, a second waveguide layer stacked together with the first waveguide layer in a direction of a thickness thereof on the substrate, the second waveguide layer having a waveguide mode different from that of the first waveguide layer, a diffraction grating formed in a region where the waveguide modes of the first and second waveguide layers overlap each other, and an electrode. When the electrical signal is applied through the electrode, the wavelength of the light coupled by the diffraction grating is changed, and light output from the second waveguide layer is modulated in accordance with the electrical signal. A method of modulating light using the above optical modulator is also disclosed.

Abstract: In an optical micromechanical method for changing the phase of guided waves and a measurement method for measuring very small mechanical displacements and/or mechanical forces or pressures, including the pressure of sound waves and ultrasonic waves, and/or accelerations, the distance d between a section (1') of an optical waveguide (1) in an integrated optic or fibre optic circuit and a phase-shifting element (5) separated from said section (1') by a gap (4) is varied by forces (6) or by thermal expansion due to changes in temperature. The phase of the guided wave (3) is thereby modulated, and reciprocally the changes in distance d and hence small mechanical displacements and the forces (6) which produce them are determined from the measured phase changes.

Abstract: A system for dynamically steering a light beam alters the path of a light beam using refraction. The light beam passes through multiple layers of optically transparent elastic material. Electrodes are attached to the bottom and top surfaces of the optically transparent layers. Voltages applied to the electrodes cause the optically transparent layers to deform. This deformation causes a change in the angle at which the light beam intercepts the surfaces of the optically transparent layers. The light beam is refracted based upon the angle of intercept and the index of refraction of the optically transparent layers. The direction of travel of the light beam can thus be controlled by varying the voltages across the electrodes.