Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample. As an example, input light in two different optical propagation modes (e.g., the first and second modes) is directed through a common input optical path to the optical probe head which sends a portion of input light in the second mode to the sample. The probe head directs both the light in the first mode and the returned light from the sample in the second mode through a common optical path to a detection module.

Abstract: This application describes designs, implementations, and techniques for optically monitoring glucose levels of patients without taking blood samples.

Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample.

Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample. As an example, input light in two different optical propagation modes (e.g., the first and second modes) is directed through a common input optical path to the optical probe head which sends a portion of input light in the second mode to the sample. The probe head directs both the light in the first mode and the returned light from the sample in the second mode through a common optical path to a detection module.

Abstract: A modulator formed with a solid state electro-optic material having a pixellated structure interconnected to a circuit on a semiconductor substrate. Silicon CMOS integrated circuit that can include random access memories (RAMs) are used as a substrate and interfaced to solid state electro-optic materials coated thereon. In particular, the electro-optic modulators are controlled by RAM cells to produce a modulation of reflected light. SRAMs can be used with connection to the SRAM cell flip-flop. DRAMs can be used with the modulator replacing the DRAM storage capacitor. The SLM thus formed can be connected to a digital computer and controlled as if were a being written to as a memory, but other IC structures can also be used. In order to enhance the modulation effects, the electro-optic material is used as the spacer for a Fabry-Perot etalon structure that is also deposited on the semiconductor substrate. PLZT is a suitable electro-optic material.

Abstract: An electrically controllable azimuth optical rotator (10) includes a first quarterwave plate (16) for receiving a first beam of electromagnetic energy (22) having a first arbitrary polarization state, and outputting a second beam (122) in response to the first quarterwave plate (16). An electric voltage controlled ferro-electric variable phase retarder (20) aligned at approximately 45 degrees to the first quarterwave plate (16) receives the second beam 122 and provides a third beam 38 in response to the retarder (20). The electric voltage controlled ferro-electric variable phase retarder (20) is characterized by a phase shift of &phgr;=2&agr;, where &agr; is a desired angle of rotation of the first arbitrary polarization state. To provide a voltage-controlled rotation, a second quarterwave plate (18) is aligned either parallel or perpendicular to the first quarterwave plate (16) for receiving the third beam (38) and outputting a fourth beam (46) in response to the retarder (20).

Abstract: A polarization mode dispersion center (306) measures PMD impairment through the cross-correlation of optical pulses. A second variable phase retarder plate (504) is oriented with polarization eigenstates at preferably 45 degree angle with respect to those eigenstates of a first variable phase retarder plate (502) to provide controllable phase retardations that can be varied and measured as an indication of PMD impairment.

Abstract: A polarization mode dispersion detector (306) measures PMD impairment through the cross-correlation of optical pulses of the light wave available from a tapped signal (40) coupled or tapped from a coupler (37). The detector (500) includes a first variable phase retarder plate (502) having a first controllable phase retardation exerted between a pair of orthogonal polarization components of the light wave in a fast axis and a slow axis of the first variable phase retarder plate (502). A second variable phase retarder plate (504) is oriented with polarization eigenstates at a preferably 45 degree angle with respect to those eigenstates of the first variable phase retarder plate (502). The second variable phase retarder plate (504) has a second controllable phase retardation exerted between a pair of orthogonal polarization components of the light wave in a fast axis and a slow axis of the second variable phase retarder plate (502).

Abstract: A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator.

Abstract: An apparatus and method for filtering an optical input is disclosed. In an illustrative embodiment, an optical input is split into polarization components along separate paths. The polarization components are then fed into a first electro-optic device that includes a set of electrodes across which a voltage is applied to adjust a wavelength transmission characteristic of the device. A section of the first device positioned between the electrodes preferably has a birefringence that is adjusted depending on the voltage applied across the electrodes. The adjusted components of the optical input are thereafter combined to produce an optical output. Accordingly, the optical input can be attenuated based on the voltage applied to electrodes of the first electro-optic device.

Abstract: An electrically controllable azimuth optical rotator (10) includes a first quarterwave plate (16) for receiving a first beam of electromagnetic energy (22) having a first arbitrary polarization state, and outputting a second beam (122) in response to the first quarterwave plate (16). An electric voltage controlled ferro-electric variable phase retarder (20) aligned at approximately 45 degrees to the first quarterwave plate (16) receives the second beam 122 and provides a third beam 38 in response to the retarder (20). The electric voltage controlled ferro-electric variable phase retarder (20) is characterized by a phase shift of &phgr;=2&agr;, where &agr; is a desired angle of rotation of the first arbitrary polarization state. To provide a voltage-controlled rotation, a second quarterwave plate (18) is aligned either parallel or perpendicular to the first quarterwave plate (16) for receiving the third beam (38) and outputting a fourth beam (46) in response to the retarder (20).

Abstract: An apparatus and method for filtering an optical input is disclosed. In an illustrative embodiment, an optical input is split into polarization components along separate paths. The polarization components are then fed into a first electro-optic device that includes a set of electrodes across which a voltage is applied to adjust a wavelength transmission characteristic of the device. A section of the first device positioned between the electrodes preferably has a birefringence that is adjusted depending on the voltage applied across the electrodes. The adjusted components of the optical input are thereafter combined to produce an optical output. Accordingly, the optical input can be attenuated based on the voltage applied to electrodes of the first electro-optic device.

Abstract: A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator.

Abstract: A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator.

Abstract: An optical modulator is provided to control the intensity of a transmitted or reflected light. In a transmission mode, a separator splits arbitrarily polarized light into two polarization rays and one is made to travel a separate path from the other. A recombiner causes the two rays to recombine at an output unless an electro-optic phase retarder changes the polarization of the two rays, in which case, both of them miss the output by an amount which is a function of the voltage on the retarder. A normally-off version with low polarization mode dispersion is obtained by changing the orientation of the recombiner. A normally-on version with low polarization mode dispersion is obtained with a passive polarization direction rotator. Similar results can be obtained in a reflection mode where the input and output are on the same side of the modulator. Versions using a GRIN lens are particularly suited to modulation of light out of and back into fiber-optic cables.

Abstract: A light beam deflector comprising a modified asymmetric Fabry-Perot (Gires-Tournois) etalon having a back reflecting and electrically conducting mirror and a front partially transmitting mirror spaced apart by an electro-optic material, there also being a transparent sheet resistor between the electro-optic material and the front mirror. The invention further comprises a pair of electrodes contacting two generally parallel edges of the transparent sheet resistor so that if different voltages are applied between the electrodes with respect to the back conducting mirror, a front to back electric field which varies in a linear manner from one electrode to the other will be produced.

Abstract: An optical modulator is provided to control the intensity of a transmitted or reflected light. In a transmission mode, a separator splits arbitrarily polarized light into two polarization rays and one is made to travel a separate path from the other. A recombiner causes the two rays to recombine at an output unless an electro-optic phase retarder changes the polarization of the two rays, in which case, both of them miss the output by an amount which is a function of the voltage on the retarder. A normally-off version with low polarization mode dispersion is obtained by changing the orientation of the recombiner. A normally-on version with low polarization mode dispersion is obtained with a passive polarization direction rotator. Similar results can be obtained in a reflection mode where the input and output are on the same side of the modulator. Versions using a GRIN lens are particularly suited to modulation of light out of and back into fiber-optic cables.

Abstract: A light beam deflector comprising a modified asymmetric Fabry-Perot (Gires-Tournois) etalon having a back reflecting and electrically conducting mirror and a front partially transmitting mirror spaced apart by an electro-optic material, there also being a transparent sheet resistor between the electro-optic material and the front mirror. The invention further comprises a pair of electrodes contacting two generally parallel edges of the transparent sheet resistor so that if different voltages are applied between the electrodes with respect to the back conducting mirror, a front to back electric field which varies in a linear manner from one electrode to the other will be produced.

Abstract: A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator.

Abstract: The invention provides a fiber-optic 2×2 switch using a dual-fiber 50:50 input coupler and a dual-fiber 50:50 output coupler. One fiber from each coupler makes contact to an inner transparent electrode on a planar layer of electro-optic material and the other fibers make contact to an outer transparent electrode on the layer. The electro-optic layer has its other side coated with a transparent electrode which is placed in optical contact with one end of a GRIN lens. The fibers are arranged so that the inner fibers are at conjugate points and the outer fibers also at conjugate points of the lens. The other end of the lens is coated with a mirror. Applying a voltage between either the inner or outer electrode changes the optical path length for the light from and to the fibers traveling through the material under the selected electrode causing the light from the two input fibers to be switched between the two output fibers. 2×N switches can be constructed by concatenating 2×2 switches.