Abstract: An electrochemical method for field monitoring of protective properties of organic coatings in seawater environment includes: Step 1: Determine the actual service environment of the coating structure and prepare the simulated electrolyte solution. Step 2: Select the anode block for testing. Step 3: Test the corrosion current and potential of the coating structure under different manual peeling areas. Step 4: Fit the peeling area model of organic coating. Step 5: Real-time monitoring of the actual service coating peeling area. Through the method, we reached to map the deteriorating state of the organic coating to metal substrate for coating on the activity of area of the effect of stripping state recognition, resolved to organic anticorrosive coating anticorrosion performance timely and accurate assessment of the actual problem, achieved by monitoring the anode current to evaluate the organic coating stripping area. This method is scientific and has good technics and broad application value.

Abstract: An electrochemical method for field monitoring of protective properties of organic coatings in seawater environment includes: Step 1: Determine the actual service environment of the coating structure and prepare the simulated electrolyte solution. Step 2: Select the anode block for testing. Step 3: Test the corrosion current and potential of the coating structure under different manual peeling areas. Step 4: Fit the peeling area model of organic coating. Step 5: Real-time monitoring of the actual service coating peeling area. Through the method, we reached to map the deteriorating state of the organic coating to metal substrate for coating on the activity of area of the effect of stripping state recognition, resolved to organic anticorrosive coating anticorrosion performance timely and accurate assessment of the actual problem, achieved by monitoring the anode current to evaluate the organic coating stripping area. This method is scientific and has good technics and broad application value.

Abstract: A lightwave communication system is provided that includes first and second optical transmitters/receivers remotely located with respect to one another. First and second optical transmission paths couple the first transmitter/receiver to the second transmitter/receiver for bidirectionally transmitting optical information therebetween. First and second doped optical fibers are respectively disposed in the first and second optical transmission paths. Optical pump energy is supplied by first and second optical pump sources. The first optical pump source generates Raman gain in the first transmission path and the second optical pump source generates Raman gain in the second transmission path. A first optical coupler is provided for optically coupling pump energy from the first pump source to the second-doped optical fiber and a second optical coupler is provided for optically coupling pump energy from the second pump source to the first doped optical fiber.

Abstract: A method and apparatus is provided for transmitting an optical signal through an optical fiber. The apparatus includes an optical signal source, which generates an optical signal having a plurality of optical channels onto which data is modulated. Each of the optical channels is defined by a different carrier wavelength. A phase modulator imparts phase modulation to the plurality of optical channels so that channels nearest a zero dispersion wavelength of the optical fiber are more closely spaced to one another than channels farthest in wavelength from the zero dispersion wavelength of the optical fiber.

Abstract: A Raman amplifier is provided that includes at least a portion of optical fiber in which an optical signal travels. The optical fiber portion may encompass all or part of the optical transmission path of an optical communication system. A pump energy unit is provided that includes first and second pump sources providing pump power at first and second wavelengths, respectively. The first and second wavelengths generate first and second gain profiles in the optical fiber portion. The first and second gain profiles overlap in wavelength. An optical coupler couples the pump power to the optical fiber portion. Since the gain profiles overlap, the Raman amplifier has a greater bandwidth than can be achieved with a pump operating at a single wavelength.

Abstract: A method and apparatus is provided for dispersion mapping that yields improved transmission performance for optical transmission systems by providing a more optimal balance between the reduction of both accumulated chromatic dispersion and nonlinear mixing. In particular, the chromatic dispersion is arranged on both a short length scale (within one amplification period) and a long length scale so that the average dispersion returns to zero. The dispersion management within one fiber span is arranged so that the magnitude of the dispersion is large in the section of the fiber span in which the optical power is large and is small in the section of the fiber span in which the optical power is small. This arrangement reduces both the amount of nonlinear mixing and the accumulated chromatic dispersion within the given fiber span.

Abstract: An optical transmission system is provided that includes a transmitting terminal, a receiving terminal remotely located from the transmitting terminal, and an optical transmission path connecting the transmitting terminal to the receiving terminal. The optical transmission path includes at least one optical amplifier such that portions of the optical transmission path located between adjacent optical amplifiers or terminals denote a transmission span. The path includes constituent optical fiber having a positive dispersion shift, dispersion compensating optical fiber having a negative dispersion shift, and dispersion slope compensating fiber having a negative dispersion slope.

Abstract: A method and apparatus provides pump energy to an optical fiber located along an optical transmission path. The optical fiber imparts Raman amplification to an optical signal traveling therein when pumped at a pump wavelength. In accordance with the method, a first beam of pump energy is generated at the pump wavelength of the optical signal and a second beam of pump energy at a wavelength one Raman Stokes order below the pump wavelength. The first beam of pump energy is introduced to the optical fiber so that it contrapropagates with respect to the optical signal. The second beam of pump energy is introduced to the optical fiber so that it co-propagates with respect to the optical signal. The second beam of pump energy does not pump the signal (thus minimizing noise) but rather serves to pump the first pump beam by the production of Raman Stokes- shifted light.

Abstract: A high-powered optical pump includes at least two sub-pumps. Each sub-pump generates light at different wavelengths. The outputs of the sub-pumps are coupled to a remote pump fiber. The resulting light transmitted on the remote pump fiber results in a lower Raman gain and Raman noise spectral peak than that generated by existing single wavelength high-powered optical pumps at the same power level. Therefore, increased power can be transmitted on the remote pump fiber in contrast to a single wavelength pump. Additionally, the total gain spectrum available for the amplification of signals is increased.