Academic Press, an imprint of Elsevier, has published a new book, "Raman Amplification in Fiber Optical Communication System," by Clifford Headley and Govind Agrawal," that it says is the first comprehensive guide to Raman amplification, a technique that is effective in any fiber to amplify the signal light as it travels through transmission fibers, compensating for inevitable signal loss. For more information, visit: books.elsevier.com    . . .    Finisar Corp., a Sunnyvale, Calif., maker of fiber optic subsystems and network test and monitoring systems, announced that Harold E. Hughes Jr. has resigned from its board of directors, effective Jan. 24.    . . .    Level 3 Communications Inc.'s European subsidiaries are providing IP services in Prague, Czech Republic. Level 3 is offering its wholesale high-speed Internet access service to target customers including ISPs, cable providers and international carriers selling communications services to Prague-based enterprises. The company said it is accomplishing the expansion using optical wavelengths leased from another telecommunications service provider.