Suppression of stimulated Brillouin scattering in optical fibers using a linearly chirped diode laser.

The output of high power fiber amplifiers is typically limited by stimulated Brillouin scattering (SBS). An analysis of SBS with a chirped pump laser indicates that a chirp of 2.5 × 10(15) Hz/s could raise, by an order of magnitude, the SBS threshold of a 20-m fiber. A diode laser with a constant output power and a linear chirp of 5 × 10(15) Hz/s has been previously demonstrated. In a low-power proof-of-concept experiment, the threshold for SBS in a 6-km fiber is increased by a factor of 100 with a chirp of 5 × 10(14) Hz/s. A linear chirp will enable straightforward coherent combination of multiple fiber amplifiers, with electronic compensation of path length differences on the order of 0.2 m.

All-fiber zero-insertion-loss add-drop filter for wavelength-division multiplexing.

We developed and fabricated an all-fiber add-drop filter by recording a Bragg grating in the waist of an asymmetric mode converter-coupler formed by adiabatic tapering and fusing of two locally dissimilar, single-mode optical fibers. The insertion loss of the device was ~0.1 dB .A narrow spectral bandwidth (<1 nm) and a large add-drop efficiency (>90%) were also demonstrated. In addition, the filter was polarization independent.

Prescription for long-lifetime, high-diffraction-efficiency fixed holograms in Fe-doped LiNbO(3).

A prescription for a material preparation and fixing technique is presented that permits a thermally fixed hologram to be recorded in Fe-doped LiNbO(3) with high diffraction efficiency and a long lifetime. In particular, a hologram with a fixed refractive-index modulation of nearly 10(-3) and a 100-year lifetime at room temperature is predicted.

Volume holographic narrow-band optical filter.

An 0.0125-nm (FWHM) bandwidth optical filter with >10% throughput, clean sidebands, f/12 speed, and a response roll-off of -40 dB/decade has been developed by using volume holography in photorefractive materials. The performance of the Accuwave holographic filter is characterized and compared with that of a Lyot filter, which is the standard for solar astronomy today. Moreover, this device represents the first commercial application of volume holography in photorefractive crystals.

Photorefractive dark conductivity in Cr-doped strontium barium niobate.

We present the theoretical and experimental results of photorefractive two-beam coupling in Cr-doped strontium barium niobate:60, using thermal excitation (i.e., dark conductivity) to model the experimentally observed temperature-dependent behavior of the two-beam coupling constant and response time.

Research on nonlinear optical materials: an assessment.

The seven papers making up this assessment are based on the Workshop on Nonlinear Optical Materials held in April 1986.