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Laser Technology News 2001 p8:

• Laser Microscopy Enhances Mohs Surgery for Skin Cancer
  Confocal laser microscopy is a new technology enabling direct imaging of biological tissue to detect tumor subtypes with minimal tissue processing or damage.
• Lambda Physik publishes new excimer laser technology handbook
  Lambda Physik has published a comprehensive guide highlighting current excimer laser applications.
• New test method can check out a new space-based solar-power system on earth
  A Purdue University engineer is saving NASA millions of dollars by devising a method to test a new type of solar-power system on Earth instead of in space.
• MEMS device compensates for gain slope in optical amplifiers
  Researchers at Bell Laboratories (Holmdel, NJ) have produced a micromechanical, optical interference device that produces changes in the slope (in dB) of its transmitted spectra via an applied voltage, without changes in attenuation level. The spectrally linear optical power equalizer (SLOPE) is less costly and easier to control than current multiple-element equalizers.
• Feedabck control fine-tunes WDM lasers
  When controlling tunable lasers for DWDM applications, two issues must be addressed. First, a look-up table (to be stored in EEPROM) is necessary to tell the microprocessor what currents should be applied to the different sections to produce a specific output power and frequency. Second, some form of feedback control is required to produce long-term stability and frequency accuracy.
• Better centering increases fiber stability
  Researchers at National Sun Yat-sen University (Kaohsiung, Taiwan) and Chunghwa Telecom Laboratories (Taoyuan, Taiwan) have studied a commonly used fiber alignment technique based on soldering fibers into metal ferrules and figured out how to carry it out with higher precision.
• Grating drops a channel in two-core fiber
  If two optical-fiber cores are brought close enough together, light traveling in one evanescently couples to the other. By making a two-core fiber and adding a Bragg grating to one of the cores, researchers at the Université Laval (Sainte-Foy, Canada) and the University of Sydney (Sydney, Australia) have created a wavelength-selective device functioning as a channel-dropping filter.
• Crossed waveguides couple at one wavelength
  Vertical couplers can serve as optical add/drop multiplexers. Their parallel geometry has two disadvantages, however: uniform coupling produces high -9-dB sidelobes, and direct coupling to optical fibers is impossible. Scientists at the University of California (Santa Barbara and Santa Cruz, CA) have developed an alternate geometry that solves both these problems.
• Heated prisms deflect beam with no moving parts
  Useful for optical switching and other applications, beam deflectors of nonmechanical design can be simpler and more reliable than their counterparts that rely on mechanical motions. Researchers at Radiant Research Inc. and The University of Texas at Austin (both in Austin, Texas) have developed an alternative that relies on the thermo-optic effect, in which a temperature change alters the refractive index.
• Market-ready blue diodes excite spectroscopists
  Performance advances in a wide variety of laser-based devices have been awaiting commercial availability of blue-emitting diode lasers. Replacing the red laser in a DVD player with a blue-emitting one, for example, increases storage capacity by about 2.5 times--but besides optical data storage, blue-violet laser diodes ultimately will benefit many other fields.

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