Diffused guides for distributed-feedback lasers

Proposed waveguide is hollow cylindrical pipe. Inside channel surface is infused with gas or metal molecules, forming periodic cross sections along entire length. Light is scattered at periodic infusions, resulting in distributed feedback. Configuration is suited for capillary gas lasers

Diffused waveguiding capillary tube with distributed feedback for a gas laser

For use in a waveguide gas laser, a capillary tube of glass or ceramic has an inner surface defining a longitudinal capillary opening through which the laser gas flows. At least a portion of the inner surface is corrugated with corrugations or channels with a periodicity Lambda where Lambda = 1/2 Lambda, Lambda being the laser gas wavelength. The tube includes a diffused region extending outwardly from the opening. The diffused region of a depth d on the order of 1 Lambda to 3 Lambda acts as a waveguide for the waves, with the corrugations producing distributed feedback. The evanescent component of the waves traveling in the diffused region interact with the laser gas in the opening, gaining energy, and thereby amplifying the waves travelling in the diffused region, which exit the diffused region, surrounding the opening, as a beam of wavelength Lambda

Acoustically controlled integrated laser for communications systems

Acoustic wave creates fringes by producing periodic stresses in substrate and in film. Laser carrier frequency is then changed by simply changing acoustical frequency. When two acoustical sources are applied off beam axis, beam can be scanned at very rapid rates

Shuttle Active-Microwave Experiments (SAMEX) program

The Shuttle active microwave experiments (SAMEX) program is reviewed. The key implementation aspects are presented

Distribution networks and electrically controllable couplers for integrated optics

The power distribution as a function of propagation distance in a network of coupled optical waveguides is determined for several interesting cases. An electrically controllable coupler is proposed and analyzed in detail. High efficiency coupling and decoupling between two optical guides can be accomplished with the use of an electrooptically generated dynamic channel, of finite length, located in between the two guides

Periodic structures in integrated optics

Thin‐film dielectric waveguides with a periodic refractive index, a periodic substrate, or periodic surface are studied. The field is determined from Maxwell's equations using Floquet's theorem. The Brillouin diagram and the interaction regions are investigated. The bandwidth and the attenuation coefficients of the interaction regions are given as a function of the optical wavelength. A number of applications in active and passive integrated optics systems are discussed

Mode conversion in periodically disturbed thin‐film waveguides

Mode conversion in a periodically perturbed thin‐film optical waveguide is studied in detail. Three different types of perturbations are considered: periodic index of refraction of the film, periodic index of refraction of the substrate, and periodic boundary. The applications in filters, mode converters, and distributed feedback lasers are discussed

Observation of the Earth by radar

Techniques and applications of radar observation from Earth satellites are discussed. Images processing and analysis of these images are discussed. Also discussed is radar imaging from aircraft. Uses of this data include ocean wave analysis, surface water evaluation, and topographic analysis

Proposed Distributed Feedback Crystal Cavities for X-Ray Lasers

The strong interest in the coherent generation and guiding of x rays is well known. Many papers have recently appeared treating different concepts of stimulated x-ray emissions, and x-ray guiding in thin films was achieved. Crystals were suggested as end reflectors to generate feedback. Here we suggest a different type of cavity using zeolite crystals that would guide the emitted x-rays and at the same time generate the necessary feedback for self-sustained oscillation

Fiber distributed feedback laser

Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs