No abstract

No abstract

Recent results indicate that certain organic molecules whose electronic structures are characterized by extended pi-molecular orbitals can exhibit significant second and third order nonlinear optical (NLO) effects [1]. Unfortunately, this same arrangement which leads to the NLO effects, can also result in essentially one-dimensional bonding coordination. This in turn means that crystals grown from these materials do not readily form good three-dimensional optical-quality crystals, but rather tend to form needles. In addition, pure organic crystals are usually bonded by weak van der Waals forces, often resulting in poor mechanical properties. Indeed, organic impurities are frequently incorporated into these systems during crystallization resulting in poor crystallinity, spurious absorptions, and low damage thresholds. This is particularly true in the case of polymeric NLO materials, where impurities result from the polymerization steps and/or starting materials.

No abstract

Using a fiber-optic stimulated-Brillouin-scattering amplifier as an active filter, we have demonstrated optical clock recovery from 5-Gbit/s return-to-zero-format optical data. Definite patterns and pseudorandom bit sequences were tested. This scheme requires no prior knowledge of the clock frequency and is well suited for operation at higher data rates.