Feature Articles

Coherent Time-Domain Far-Infrared Spectroscopy; Direct Laser Generation of 27-FSEC Ultrashort Optical Pulses

A new approach to far-infrared spectroscopy uses nonlinear optics and femtosecond optical pulses to generate and measure extremely short electromagnetic transients whose frequency spectra span a large portion of the entire far-infrared spectral range.

by D. H. Auston and K. F. Cheung
Shaping of Ultrashort Optical Pulses; Ultrashort Pulse-Pumped Dye Lasers

A technique has been developed which allows arbitrary shaping of ultrashort optical pulses.

by J. P. Heritage, R. N. Thurston, and A. M. Weiner
Extremely Broadband Lasers and Detectors; Ultrashort Pulses from Semiconductor Lasers

Recently, the bandwidths of long-wavelength optical sources and detectors have more than doubled, opening up new applications in optical transmission systems.

by J. E. Bowers, C. A. Burrus
Ultrashort Pulses from Semiconductor Lasers

Using ultrashort light pulses for communications systems will require suitable commercial lasers, rather than the cumbersome laboratory models available to date. AT&T Bell Laboratories has recently developed a mode-locking technique for generating just such pulses in commercial laser diodes.

by D. J. Eilenberger, Y. Silberberg, P. W. Smith, Bell Communications Research; and D. A. B. Miller
LEDS as High-Bit-Rate Sources for Single-Mode Fiber

Future broadband optical communications applications, such as feeder systems to homes and businesses, favor single-mode fibers because of their enormous potential for upgrading as services and technology progress. These applications require the reliability and cost advantages offered at present only by light-emitting diodes (LEDs).

by P. W. Shumate, M. B. Romeiser, and N. K. Cheung
High Speed Optical Heterodyne Transmission in Single-Mode Fiber

With recent progress in lightwave technology, optical heterodyne and homodyne detection methods, commonly referred to as coherent communications, are becoming increasingly viable. The techniques are important to future lightwave communications systems because they offer substantially higher receiver sensitivity, as well as the ability to tune to a large number of channels with small frequency separation.

by R. S. Vodhanel, J. L. Gimlett, R. D. Standley, and N. K. Cheung
Array of Picosecond GAAS Optical Gates

Current efforts to reduce the switching times of optical bistable devices, and to fabricate large device arrays, are laying the groundwork for future integration of these devices into a working computer or signal processor.

by N. Peyghambarian and H. M. Gibbs
High-Temperature Color Center Applications

In phase-conjugate optics, new applications of color centers have been demonstrated. Research on color centers may yield improved, solid state versions of liquid devices—tunable lasers, Q switches, and mode-lockers—which incorporate crystals. These solid systems would be less complicated than liquid ones, and well suited for communications and remote sensing applications.

by S. C. Rand
Photon-Gated Spectral Hole-Burning; Shorter Optical Pulses by Pulse Compression

Recently, two-color photon-gated persistent spectral hole-burning (PHB) was observed for the first time in an inorganic material (BaClF:Sm2+) and an organic material (carbazole in boric acid glass). By demonstrating that nondestructive reading of spectral holes is possible, a new dimension for optical storage of information has been opened up.

by W. E. Moerner, R. M. Macfarlane and R. M. Shelby