The BandXchange is a "pure optical" processor capable of all-optical wavelength band conversion, phase conjugation and spectral inversion with bit-rate and protocol transparency and negligible added noise. According to its developer, Lightbit Corp. of Mountain View Calif., the device is based on nonlinear optics in an optical chip, not a semiconductor. It uses light to process light with the advantages of speed, transparency and parallel processing.The BandXchange also can be used as a phase conjugator at the midpoint of a link, compensating for chromatic dispersion and nonlinearities in the entire link. The single unit replaces up to 12 conventional compensation units deployed at 12 sites, improving signal-to-noise ratios and reducing amplification requirements.The BandXchange increases the functionality and efficiency of optically switched networks by eliminating wavelength contention and providing software-controlled reconfigurability. This functionality will allow operators to run the network more economically by fully utilizing capacity, improving service velocity and reducing response time to customers through faster provisioning, reconfiguration and restoration. The device can also shift C-band channels to the L-band, providing a bridge between networks.