Optical transmission system including repeatered and unrepeatered segments

An optical communication system comprising:

• a trunk path configured for communicating a plurality of optical data signals, each at a different associated wavelength, between first and second trunk path cable stations, said trunk path being at least partially submarine and comprising a plurality of repeaters, said repeaters being spaced from each other along said trunk path according to a repeater spacing in a range from about 35 km to 120 km and being coupled to said trunk path for receiving power from power feed equipment in at least one of said first and second cable stations;
• and
• at least one branch segment configured for communicating signals at said wavelengths between said trunk path and a branch segment cable station, said branch segment being at least partially submarine and having a first end coupled to said trunk path through a submarine branching unit and a second end coupled to said branch segment cable station, said branch segment having a length greater than an average repeater spacing and having no repeaters disposed along the length thereof,
• said branch segment cable station comprising a pump source configured to pump at least a portion of said branch segment to provide Raman amplification to said signals at said wavelengths, and
• a first one of said repeaters being disposed along said trunk path adjacent a first side of said branching unit and a second one of said repeaters being disposed along said trunk path adjacent a second side of said branching unit, said first and second ones of said repeaters being configured for repeater spacing greater than said average repeater spacing and being disposed along said trunk path at a distance of 20 km or less from said branching unit.