Stephen Friberg - Academia.edu (original) (raw)

Papers by Stephen Friberg

The Journal of Bahá’í Studies, Mar 22, 2024

This paper is an exploration of Shoghi Effendi's statement that Bahá'u'lláh's Reve-1 I very much ... more This paper is an exploration of Shoghi Effendi's statement that Bahá'u'lláh's Reve-1 I very much appreciate the continuing inspiration and guidance from

Quantum Electronics and Laser Science Conference, May 10, 1992

A photon-number quantum nondemolition (QND) measurement theory that takes dissipative losses into... more A photon-number quantum nondemolition (QND) measurement theory that takes dissipative losses into account is presented. A QND measurement criterion is developed to determine the feasibility of QND measurements in a lossy optical medium. Using an analysis based on loss-error characteristics, we examine a lossy Kerr medium. We obtain restrictions on the losses and requirements for the nonlinearity and signal and probe powers necessary to observe the QND eff'ect. We calculate the expected results for an experimental system meeting such requirements. We conclude that QND measurements are possible in existing media.

Optics Letters, Oct 1, 1988

We report all-optical switching of 100-fsec pulses in a fused-quartz dual-core-fiber directional ... more We report all-optical switching of 100-fsec pulses in a fused-quartz dual-core-fiber directional coupler. The length of the device is 0.5 cm, and the switching power is 32 kW. Pulses are routed to either of two separate fiber guides, depending on the input power. Measurements of pulse reshaping by the nonlinear coupler provide compelling evidence of the device's ability to response on a femotosecond time scale.

Journal of The Optical Society of America B-optical Physics, Mar 1, 1985

The necessary and sufficient conditions on the gain of the linear amplifier are determined under ... more The necessary and sufficient conditions on the gain of the linear amplifier are determined under which the light output exhibits sub-Poissonian photon statistics or squeezing. It is found that for these effects the intensity gain must not exceed 2 under any circumstances. It is also shown that there exists a weaker sufficiency condition on the gain above which all nonclassical features of the field disappear. This suggests the possibility that other quantum effects may persist in the intermediate, still unexplored, domain of operation of the amplifier.

Conference on Lasers and Electro-Optics, Apr 26, 1987

Optics Letters, Jul 15, 1992

Bound higher-order solitons, sometimes called breather solitons, can easily be broken apart by sm... more Bound higher-order solitons, sometimes called breather solitons, can easily be broken apart by small perturbations. We discuss the conditions for breakup of bound solitons and describe a method to determine the details of the soliton breakup. Using this method, we illustrate the breakup of bound solitons by optical filters, by asymmetric FM modulation (not AM or symmetric FM modulation), and by superposition with other optical pulses.

Japanese Journal of Applied Physics, Dec 1, 1994

We use simulations of hydrodynamics coupled with full general relativity to investigate the gravi... more We use simulations of hydrodynamics coupled with full general relativity to investigate the gravitational waves produced by a star colliding with a massive black hole when the star's tidal disruption radius lies far outside of the black hole horizon. We consider both main-sequence and white-dwarf compaction stars, and nonspinning black holes, as well as those with near-extremal spin. We study the regime in between where the star can be accurately modeled by a point particle, and where tidal effects completely suppress the gravitational wave signal. We find that nonnegligible gravitational waves can be produced even when the star is strongly affected by tidal forces, as well as when it collides with large angular momentum. We discuss the implications that these results have for the potential observation of gravitational waves from these sources with future detectors.

Annual Meeting Optical Society of America, 1988

One factor limiting interest in optical bistable devices is their relatively slow speed. For exam... more One factor limiting interest in optical bistable devices is their relatively slow speed. For example, GaAs/AIGaAs MQW nonlinear etalon devices have switch-on times of 1 ps1 but switch-off times in excess of 150 ps.2 Similarly, ZnS and ZnSe thermal etalons can switch on more quickly than they switch off because of slow thermal relaxation times. This places a revere restriction on rates of operation. To circumvent this problem, we propose the use of nonlinear etalons in an optical time division multiplexing/demultiplexing system and describe a transmitter (two nonlinear etalons and an optical delay line) that can produce optical pulses as short as the etalon switch-on times. Pulses from the transmitter for each channel are coupled in a time sequence into a waveguide. The process is repeated after the etalon carrier-recombination (thermal relaxation) time has elapsed. Demultiplexing is carried out in a similar way. Etalon time division multiplexing results in bit rates much larger than possible for individual devices. For GaAs/AIGaAs etalons with 150-ps recombination times, bit rates from 6.7 to 500 Gbit/s should be obtainable, depending on the number of channels used. We experimentally demonstrate the feasibility of the multiplexing and demultiplexing schemes using ZnS thermal etalon devices.

Annual Meeting Optical Society of America, 1985

When a laser beam interacts with a nonlinear crystal, some of the incident photons fission into t... more When a laser beam interacts with a nonlinear crystal, some of the incident photons fission into two lower frequency signal and idler photons through the process of spontaneous parametric downconversion. It is shown that, as a result of the strong positive correlation between signal and idler photons, the normalized intensity cross-correlation function λ12(τ) should be inversely proportional to the downconverted light intensity and ideally should be given by the inverse of the mean number of photons counted in the resolving time. This unusual relationship, which is a reflection of the quantum mechanical character of the downconverted optical field, has been confirmed in photoelectric counting measurements. The experiment makes use of the light from an argon-ion laser oscillating at 351.1 nm interacting with an 8-cm long crystal of KDP. The downconverted light is extracted at 633.5 and 788.0 nm in two directions that satisfy the phase-matching condition and is allowed to fall on two counting photomultipliers. The output pulses are fed to a time-to-digital converter that yields the cross-correlation function.

Annual Meeting Optical Society of America, 1986

Ultrarapid (subpicosecond) optical switching and signal processing elements should find important... more Ultrarapid (subpicosecond) optical switching and signal processing elements should find important applications in future communication and computing systems. Glasses with fast (< 100-fs) electronic third-order susceptibilities could be used to fabricate ultrarapid switches. These nonlinearities, described by the nonlinear index coefficient n2, are compared with slow thermal index changes for various glasses. A degenerate four-wave mixing (DFWM) technique using a 250-ns train of 80-ps pulses from a mode-locked Q-switched Nd:YAG laser was used to measure n2. Thermal index changes were obtained by comparison of the DFWM signal from initial and final pulses of the pulse train. Results for leaded glasses agree with previous reports, with n2 of SF-59 equal to 19% of that of CS2. Titanium glasses, e.g., Hoya FDS-90, have an n2 that is 7 % that of CS2, and n2 does not increase with linear index as for leaded glasses. The observed thermal index changes are small, as expected for very low absorption coefficients. We define a figure of merit to help compare nonlinear materials for use in optical switches. It is the ratio of the (fast) nonlinear index change necessary to produce switching to the accompanying (slow) thermal index change. We show that some optical glasses appear to have higher figures of merit than any other nonlinear optical material. We conclude with a discussion of some possible configurations for glass all-optical switches.

Annual Meeting Optical Society of America, 1987

PhDT, 1986

This thesis deals with intensity correlation measurement methods as they apply to the study of li... more This thesis deals with intensity correlation measurement methods as they apply to the study of light generated by a parametric downconversion process. The correlation properties of light can be used to distinguish between quantum mechanical light and classical light, where ...

Conference on Lasers and Electro-Optics, May 8, 1994

Springer series in electrophysics, 1990

We introduce an ultrafast all-optical switch based on two-color soliton collisions. We describe a... more We introduce an ultrafast all-optical switch based on two-color soliton collisions. We describe a Mach-Zehnder interferometer that responds to but does not alter an input signal soliton.

Conference on Lasers and Electro-Optics, Apr 25, 1988

Quantum Electronics and Laser Science Conference, May 12, 2000

Summary form only given. Correlated and entangled single photon states have made possible many fu... more Summary form only given. Correlated and entangled single photon states have made possible many fundamental studies in quantum optics such as the Bell-type test of hidden variables and non-locality, explorations of quantum interference properties, and investigations of quantum information processing and quantum communications technologies such as quantum cryptography, quantum computing, and quantum teleportation. These correlated single photon states are traditionally

Physical Review Letters, Jan 3, 2000

Quantum mechanics allows quantum nondemolition (QND) variables to be measured without being chang... more Quantum mechanics allows quantum nondemolition (QND) variables to be measured without being changed. This requires QND variables to be initially in an eigenstate and measurement backaction noise to be directed into conjugate variables. Experimental demonstrations thus require two measurements: the first to collapse variables toward an eigenstate and the second to show results identical to the first. Here, we report results from two successive soliton-collision QND measurements that optical correlation measurements show to be nearly identical.

Optics Communications, 1984

It is shown that a hybrid of degenerate parametric down-conversion and harmonic generation leads ... more It is shown that a hybrid of degenerate parametric down-conversion and harmonic generation leads to squeezing free from sub-poissonian photon statistics, but with the advantage that a coherent reference light beam is available for homodyning.

IEEE Journal of Quantum Electronics, Dec 1, 1987

... FRIBERG AND SMITH: NONLINEAR GLASSES FOR ULTRAFAST SWITCHES ... The operation of all-optical ... more ... FRIBERG AND SMITH: NONLINEAR GLASSES FOR ULTRAFAST SWITCHES ... The operation of all-optical waveguide devices can be best understood by considering two important examples ... intensity dependent index change in one of the legs induced by a control beam PC of a ...

Journal of The Optical Society of America A-optics Image Science and Vision, 1984

It is pointed out that a method recently described by Hillery and Zubairy can be generalized to y... more It is pointed out that a method recently described by Hillery and Zubairy can be generalized to yield the multitime correlation function in any order for an interacting quantum field in the form of a phase-space average. The correlations are expressible as c-number integrals with the help of the coherent-state propagator, but the associated phase-space density is complex.