Multi-stage optical amplifier and broadband communication system

A broadband booster amplifier, comprising:

• a plurality of transmitters transmitting a plurality of wavelengths;
• a combiner coupled to the plurality of transmitters;
• an optical fiber coupled to the combiner, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber, wherein a signal introduced through the signal input port propagates from the first stage amplifier to the second stage amplifier;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of the pump radiation from the second to the first length of amplifier fiber is substantially blocked;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband pre-amplifier, comprising:

• an optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation from the second to the first length of amplifier fiber is substantially blocked;
• a splitter coupled to the signal output port;
• a plurality of receivers coupled to the splitter;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband communication system, comprising:

• a transmitter;
• an optical fiber coupled to the transmitter, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• and
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation of from the second to the first length of amplifier fiber is substantially blocked;
• a receiver coupled to the optical fiber;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband communication system, comprising:

• a transmitter;
• an optical fiber coupled to the transmitter, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• and
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation from the second to the first length of amplifier fiber is substantially blocked;
• at least one in-line broadband amplifier coupled to the optical fiber;
• a receiver coupled to the in-line broadband amplifier;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband communication system, comprising:

• a transmitter;
• a broadband booster amplifier;
• an optical fiber coupled to the broadband booster amplifier, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• and
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation of from the second to the first length of amplifier fiber is substantially blocked;
• a receiver coupled to the optical fiber;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband communication system, comprising:

• a transmitter;
• an optical fiber coupled to the transmitter, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation from the second to the first length of amplifier fiber is substantially blocked;
• a broadband pre-amplifier coupled to the optical fiber;
• a receiver coupled to the broadband pre-amplifier;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A broadband communication system, comprising:

• a transmitter;
• a booster broadband amplifier coupled to the transmitter;
• an optical fiber coupled to the broadband booster amplifier, the optical fiber including at least a first Raman amplifier fiber and a second Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source and at least two pump sources, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the first Raman amplifier fiber being positioned between the signal input port and the first pump input port and the second Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the second Raman amplifier fiber and the signal output port;
• a first lossy member positioned between the first pump input port and the signal output port, wherein the lossy member is lossy in at least one direction and passage of pump radiation from the second to the first length of amplifier fiber is substantially blocked;
• a broadband pre-amplifier coupled to the optical fiber;
• a receiver coupled to the broadband pre-amplifier;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.

A multi-stage optical amplifier, comprising:

• an optical fiber including at least a distributed Raman amplifier fiber and a discrete Raman amplifier fiber, the optical fiber configured to be coupled to at least one signal source that produces at least a signal wavelength λs and at least two pump sources that collectively produce a pump beam of wavelength λp, wherein pump wavelength λp is less than signal wavelength λs, the first Raman fiber amplifier having an optical noise figure of less than 8 dB and lower noise than the second Raman fiber amplifier, and the second Raman fiber amplifier having a gain level of at least 5 dB;
• a signal input port coupled to the optical fiber;
• a signal output port coupled to the optical fiber;
• a first pump input port, the distributed Raman amplifier fiber being positioned between the signal input port and the first pump input port and the discrete Raman amplifier fiber being positioned between the first pump input port and signal output port;
• a second pump input port coupled to the optical fiber and positioned between the discrete Raman amplifier fiber and the signal output port;
• and
• wherein the signal flows in a first direction and the pump beam flows in a reverse direction relative to the first direction.