• Online Features |
• Industry News |
• Product Highlights |
• Technology News |
• Archives Home

Laser Technology News 2001 p9:

• All-optical interferometer provides efficient signal regeneration
  Researchers from the Technical University of Denmark (Lyngby, Denmark) and from the Alcatel Corporate Research Center (Marcoussis, France) have demonstrated all-optical wavelength conversion at 40 Gbit/s using an SOA-based, all-active Mach-Zender interferometer (MZI).
• Bidirectional add/drop could help rings heal
  Jang-Won Park and Chang-Hee Lee of the Korea Advanced Institute of Science and Technology (Taejon, Korea) have demonstrated a bidirectional add/drop amplifier (BADA) that can be implemented with only one N × N arrayed waveguide grating multiplexer. Equally important, no optical bandpass filter is required to suppress relative intensity noise.
• Water-free process makes high-bandwidth fiber
  Researchers at Lucent Technologies (Murray Hill, NJ, and Norcross, GA), Rutgers University (New Brunswick, NJ), and the Massachusetts Institute of Technology (Cambridge, MA) have experimentally clarified the physics of the contamination process involved in making fused-silica optical fibers, and used their results to make dry fiber that lacks the usual absorption peaks.
• FIber laser switches wavelengths electrically
  Wavelength-tunable and switchable lasers are becoming more important to WDM. Because rare-earth-doped fiber lasers have a large gain bandwidth, they make ideal candidates for tunable sources; indeed, tunability has been demonstrated in actively modelocked fiber lasers. But existing techniques for changing wavelength in fiber lasers require changing the modelocked frequency, adding complexity to the system.
• Mixing EDFAs and Raman amplifiers improves long-haul transmission
  Researchers at Alcatel Submarine Networks (Clichy, France) have found that combining a 980-nm-pumped erbium-doped fiber amplifier (EDFA) with a Raman amplifier gives both an improvement in signal-to-noise ratio (SNR) and the high gain compression and output power common to erbium-doped fiber amplifier (EDFAs).
• Hybrid polymer-silica waveguides provide tunability
  Air-silica microstructure fibers allow a diverse range of guided-mode properties to be created. The results can produce unique spectral characteristics when long and short-period gratings are written into photosensitive regions. In addition, it is possible to introduce polymers into the air regions to produce hybrid polymer-silica waveguides that allow enhanced tunability of propagation properties.
• Tabletop-terrawatt lasers may explore particle physics
  High-energy lasers could change particle-accelerator design by producing relativistic electrons over a much shorter distance than existing machines.
• Cavity ringdown measures trace concentrations
  Intensity decay of pulsed laser sources in a highly reflective cavity permits cavity ringdown laser absorption spectroscopy to measure sub-parts-per-million levels of gaseous species.
• Intelligent nanostructures report on their environment
  Researchers at Sandia National Laboratories (Albuquerque, NM) and the University of New Mexico (Albuquerque) have developed intelligent nanostructures that report on their environment by changing color from blue to fluorescent red under mechanical, chemical, or thermal stress.
• In space, even a small wrinkle reduces efficiency of lightweight mirrors
  While inflatable structures may be ideal for many space applications, such as solar collectors, very small wrinkles may make enormous mirrors based on this concept impractical.

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |