Showing papers by "Amnon Yariv published in 1979"

Compensation for channel dispersion by nonlinear optical phase conjugation.

Abstract: It is proposed that the process of nonlinear optical phase conjugation can be utilized to compensate for channel dispersion and hence to correct for temporal pulse broadening. Specifically, a four-wave nonlinear interaction is shown to achieve pulse renarrowing. Spectral bandwidth constraints of the input pulse are presented for typical phase-conjugate interaction parameters.

A theoretical and experimental investigation of the modes of optical resonators with phase-conjugate mirrors

Abstract: We present an analysis of resonator properties for a cavity bounded by a phase conjugate mirror, which is generated by a degenerate four-wave nonlinear optical interaction. Using a ray matrix formalism to describe the conjugate mirror, resonator stability conditions are derived. Longitudinal and transverse mode characteristics are discussed. Results are compared with an experiment where laser oscillation was observed at 6943 A using carbon disulfide as the nonlinear interacting medium comprising the phase conjugate mirror.

Theory of cw Raman oscillation in optical fibers

Abstract: A theory for Raman fiber laser oscillators is presented. The Stokes output and the residual pump power are shown to be calculable from a knowledge of the input pump power and the fiber characteristics. The evolution of the pump and the Stokes waves along the fiber are also obtained. The threshold pump power and the oscillation condition are considered. Pump depletion is incorporated in the analysis and is shown to be the dominant saturation effect present in a Raman fiber laser.

Monolithic integration of an injection laser and a metal semiconductor field effect transistor

Abstract: A new laser structure, the ’’T‐laser’’, has been monolithically integrated with a MESFET on a semi‐insulating GaAs substrate. Integration is achieved by means of a compatible structure in which the optically active layer of the laser also serves as the electrically active layer of the MESFET. Direct modulation of the laser by means of the transistor is demonstrated.

A monolithically integrated optical repeater

Abstract: A monolithically integrated optical repeater has been fabricated on a single‐crystal semi‐insulating GaAs substrate. The repeater consists of an optical detector, an electronic amplifier, and a double heterostructure crowding effect laser. The repeater makes use of three metal semiconductor field effect transistors, one of which is used as the optical detector. With light from an external GaAlAs laser incident on the detector, an overall optical power gain of 10 dB from both laser facets was obtained.

Coherence of a room-temperature CW GaAs/GaAlAs injection laser

Abstract: The temporal coherence of a stripe-geometry double-heterojunction GaAs/GaAlAs laser operating CW at room temperature was determined. A heterodyne detection scheme was used involving the mixing of the laser field with a frequency-shifted and time-delayed image of itself in an interferometer. Because the laser device oscillated in several longitudinal modes, the autocorrelation function of its output exhibited resonances for specific time delays. The rate at which the amplitude of these resonances decreased with increasing time delays provided a measure of an apparent coherence length associated with individual longitudinal modes. The coherence length, so defined, was found to increase linearly with drive current in excess of threshold. This observation is interpreted as evidence that the intrinsic linewidth of a longitudinal mode is inversely proportional to the coherent optical power in that mode. Apparent coherence lengths were a few centimeters for a few milliwatts of total optical power emitted per facet. For a perfectly balanced interferometer, a sharp heterodyne beat signal was also observed when the laser device was operated considerably below threshold, i.e., in the LED mode.

Continuous backward-wave generation by degenerate four-wave mixing in optical fibers

Abstract: We report on the observation of cw backward-wave generation using degenerate four-wave mixing in a nonresonant medium. The interaction took place inside a 3-m-long CS2-filled 4-µm i.d. optical fiber. With a pump power of only 6 mW inside the fiber, a backward-wave conversion efficiency of 0.45% has been observed, which is in reasonable agreement with theoretical predictions.

Transient four-wave mixing and real time holography in atomic systems

Abstract: The problem of transient four-wave mixing with noncoincident optical pulses is analyzed using the formalism of the time evolution and the density matrix operators. The results are relevant to problems involving real time holography and wave conjugation. The treatment establishes a bridge between the conventional formalisms of nonlinear optics and of photon echoes.

Phase-Conjugate Optics,

Abstract: A new research area in coherent optics has emerged and has been receiving increasing attention from many scientists as its important applications are recognized. Phase conjugate optics is the name which seems to have attached itself to this new field. The main feature of phase conjugate optics is the generation of an electromagnetic wave with a phase distribution which is, at each point in space, the reversal of that of an arbitrary incoming monochromatic wave. The wavefront, after being generated, proceeds to propagate in the opposite direction, retracing in reverse the path of the incoming wave. Thus, the phase reversal or conjugation process results in what is frequently called a time-reversed replica of the incident wave. If we consider, as an example, an incoming spherical wavefront which, diverging from a point, has a radius of curvature R, its conjugate-replica will be an outgoing spherical wavefront converging toward the same point and with a radius of curvature -R. Phase conjugation techniques have been used in the past for imaging through phase distorting media; well known examples can be found in holography [1] and adaptive optical systems [2]. The new and attractive feature, which differentiates phase conjugate optics from the previous techniques, is the use of nonlinear optical mixing to generate in real time without the need for intermediate electronics, and with amplification if desired, a time-reversed replica of an incident wave.

The coupled-mode formalism in guided-wave optics

Abstract: The problem of propagation and interaction of optical radiation in dielectric waveguides is cast in the coupled-mode formalism This approach is useful for treating problems involving energy exchange between modes A derivation of the general theory is followed by application to the specific cases of electrooptic modulation, photoelastic and magnetooptic modulation, and optical filtering Also treated are nonlinear optical applications such as second-harmonic generation in thin films and phase matching