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A large-mode Fabry-Perot cavity has been developed for power enhancement of UV laser. Megawatt peak power has been realized inside the cavity through power recycling of 50ps/402.5MHz UV pulses operating in a 10μs/10Hz burst mode.
Quantum transduction between microwaves and optics can be realized by quantum teleportation if given reliable microwave-optical entanglement, namely, entanglement-based quantum transduction. To realize this protocol, an entangled source with a high fidelity between the two frequencies is necessary. Here, we study microwave and optical entanglement generation based on a generic cavity electro-optomechanical system in the strong coupling regime. Splittings are shown in the microwave and optical output spectra and the frequency entanglement between the two modes is quantified. We show that entanglement can be straightforwardly encoded in the frequency-bin degree of freedom and propose a feasible experiment to verify entangled photon pairs. The experimental implementation is systematically analyzed, and the preferable parameter regime for entanglement verification is identified. An inequality is given as a criterion for good entanglement verification with analysis of practical imperfections.
We present the development of a single-mode spatial filter array for the nulling coronagraph application. The development consists of two generations of fiber array designs and a Zygo-interferometer based lens array to fiber array alignment methodology. We discuss the use of large mode field diameter (MFD) fibers to relax fiber placement tolerance of the fiber array. The pros and cons of using the Photonic Crystal Fiber (PCF) for building the array are discussed. The future plan for implementing a 1000-channel class, single-mode spatial filter array is described.
The strain sensitivity of an optical fiber interferometer developed for the detection of pulsed ultrasonic waves in solids has been calibrated. The optical paths in both signal and reference arms of the interferometer are through similar 2 m lengths of ITT-110 single mode fibers mode stripped by index matching at both ends and attached to opposite sides of a 30 cm plexiglas bar 0.3 cm thick. Light from the output ends of both fibers was superimposed to form an interference fringe pattern that was interrogated in the far field to give a signal proportional to the differential optical fiber path length. Strain sensitivity was determined by comparing data obtained by clamping and bending the bar at different lengths to simple cantilever beam theory. Calibration indicates a minimum theoretical detectable strain of less than 10 to the -10.
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The development of a multimode optical sensor (MMOS) is reported. The objectives, accomplishments, and history of the program are presented along with a description of the MMOS. A collection of design studies, tradeoff studies, and test results are included.
An evaluation test series was performed on the unit to develop realistic specifications for a similar device for use on the orbiter vehicle. Tests included sensitivity, target dynamic range, tracking angular rate, external magnetic field effects, and photocathode uniformity. Several demonstrations of operation under automatic control were also prepared, using a desk calculator for numerical control and for subsequent reduction of data derived from the test.
The strain sensitivity of an optical fiber interferometer developed for the detection of pulsed ultrasonic waves in solids was calibrated. Light from the output ends of both fibers was superimposed to form an interference fringe pattern that was interrogated in the far field to give a signal proportional to the differential optical fiber path length. Strain sensitivity is determined by comparing data obtained by clamping and bending the bar at different lengths to simple cantilever beam theory. A minimum theoretical detectable strain of less than 10 to the minus 10th power is indicated.
A 250-Mbit/s three-station fiber-optic ring local computer network was built and successfully demonstrated. A conventional token protocol was employed for bus arbitration to maximize the bus efficiency under high loading conditions, and a non-return-to-zero (NRS) data encoding format was selected for simplicity and maximum utilization of the ECL-circuit bandwidth.
A strain sensor uses an optical fiber including a strain sensitive portion and at least one strain insensitive portion. The strain sensitive portion is mounted on the surface of a structure at a location where a strain is desired to be measured. The strain insensitive portion(s) may be fused to the strain sensitive portion to transmit light therethrough, so that the resulting pattern may be detected to determine the amount of strain by comparison with a similar fiber not subjected to strain, or with the light pattern produced when the fiber is not under strain.
Optical microsphere cavities, with their exceptionally high quality-factor and submillimeter dimensions, present an attractive new building block for fiber optics and photonics applications.
Zinc oxide (ZnO) nanowires are widely studied for use in ultraviolet optoelectronic devices, such as nanolasers and sensors. Nanowires (NWs) with an MgO shell exhibit enhanced band-edge photoluminescence (PL), a result previously attributed to passivation of ZnO defects. However, we find that processing the ZnO NWs under low oxygen partial pressure leads to an MgO-thickness-dependent PL enhancement owing to the formation of optical cavity modes. Conversely, processing under higher oxygen partial pressure leads to NWs that support neither mode formation nor band-edge PL enhancement. High-resolution electron microscopy and density-functional calculations implicate the ZnO m-plane surface morphology as the key determinant of core-shell structure and cavity-mode optics. A ZnO surface with atomic steps along the m-plane in the c-axis direction stimulates the growth of a smooth MgO shell that supports guided-wave optical modes and enhanced UV PL. On the other hand, a smoother ZnO surface leads to nucleation of a rough cladding layer which supports neither enhanced UV PL nor optical cavity modes. Finite-element analysis shows a clear correlation between allowed Fabry-Perot and whispering gallery modes and enhanced UV-PL. Finally, these results point the way to fabricating ZnO/MgO core-shell nanowires for more efficient UV nanolasers, scintillators, and sensors.
Propagation of optical-waveguide modes in dielectric slab bisected by metal sheel
Examples herein relate to polarization diversity optical interface assemblies including a single mode optical fiber and first and second grating couplers disposed on a substrate. The first and second grating couplers are coupled to first and second waveguides, respectively. The assemblies further includes an optical connector to couple light between the single mode optical fiber and each of the first and second grating couplers. The optical connector includes a ferrule and a walk-off crystal. The ferrule is coupled to a portion of the single mode optical fiber. The walk-off crystal is configured to spatially separate the light into first and second orthogonal polarization modes prior to passing through the respective first and second grating couplers and/or combine the first and second polarization modes of the light prior to passing through the single mode optical fiber.