Bidirectional WDM optical communication systems with bidirectional optical amplifiers

A bidirectional wavelength division multiplexed optical communication system comprising:

• a first plurality of optical transmitters for transmitting a plurality of optical communication signals in a first, nominally west-east, direction;
• a first optical combiner having inputs for communicating with each of the west-east optical transmitters and an output for outputting a west-east wavelength division multiplexed optical communication signal comprised of the plurality of west-east optical communication signals;
• an optical transmission path including nominally west and east access ports having a west access port optically communicating with the output port of the first optical combiner for receiving the west-east wavelength division multiplexed optical communication signal;
• a second plurality of optical transmitters for transmitting a plurality of optical communication signals in a second, nominally east-west, direction;
• a second optical combiner having inputs for communicating with each of the east-west optical transmitters and an output for outputting an east-west wavelength division multiplexed optical communication signal comprised of the plurality of east-west optical communication signals, the output of the second optical combiner optically communicating with an east access port of the optical transmission path;
• a bidirectional optical amplifier optically communicating with the optical transmission path for optically amplifying the west-east wavelength division multiplexed optical communication signal and for optically amplifying the east-west wavelength division multiplexed optical communication signal, the bidirectional optical amplifier comprising:
• a first optical circulator having first, second, third, and fourth circulator ports, the first port of the first optical circulator optically communicating with the optical transmission path to receive the west-east wavelength division multiplexed optical communication signal;
• a second optical circulator having first, second, third, and fourth circulator ports, the first port of the second optical circulator optically communicating with the optical transmission path to receive the east-west wavelength division multiplexed optical communication signal;
• a first set of one or more Bragg gratings configured to reflect optical wavelengths within the west-east wavelength division multiplexed optical communication signal optically communicating with the second port of the first optical circulator;
• a second set of one or more Bragg gratings configured to reflect optical wavelengths within the east-west wavelength division multiplexed optical communication signal optically communicating with the second port of the second optical circulator;
• a first gain block optically communicating with the third port of the first optical circulator and with the fourth port of the second optical circulator;
• a second gain block optically communicating with the third port of the second optical circulator and with the fourth port of the first optical circulator;
• and
• first and second receiving systems optically communicating with the optical transmission path for respectively receiving the west-east and east-west wavelength division multiplexed optical communication signals.

A bidirectional optical amplifier for optically amplifying nominally west-east wavelength division multiplexed optical communication signals and for optically amplifying nominally east-west wavelength division multiplexed optical communication signals in a bidirectional wavelength division multiplexed optical communication system comprising:

• a first optical circulator having first, second, third, and fourth circulator ports, the first port of the first optical circulator configured to receive a west-east wavelength division multiplexed optical communication signal;
• a second optical circulator having first, second, third, and fourth circulator ports, the first port of the second optical circulator configured to receive an east-west wavelength division multiplexed optical communication signal;
• a first set of one or more Bragg gratings configured to reflect optical wavelengths within a west-east wavelength division multiplexed optical communication signal optically communicating with the second port of the first optical circulator;
• a second set of one or more Bragg gratings configured to reflect optical wavelengths within an east-west wavelength division multiplexed optical communication signal optically communicating with the second port of the second optical circulator;
• a first gain block optically communicating with the third port of the first optical circulator and with the fourth port of the second optical circulator;
• and
• a second gain block optically communicating with the third port of the second optical circulator and with the fourth port of the first optical circulator.