Abstract: The communication system has first and second optical systems and an optical feed fiber in communication with the first optical system and arranged to convey a feeder optical signal to the second optical system. The first optical system includes a multiplexer configured to multiplex/demultiplex between a first optical line terminal signal, a second optical line terminal signal, and the feeder optical signal. The feeder optical signal includes the first optical line terminal signal and the second optical line terminal signal. The first optical line terminal signal includes a first upstream free spectral range and a first downstream free spectral range. The second optical line terminal signal includes a second upstream free spectral range and a second downstream free spectral range. The second optical system is in communication with the optical feed fiber and is configured to multiplex and demultiplex between the feeder optical signal and optical network unit signals.

Abstract: A method includes receiving a mode control signal indicative of a current-mode or a voltage-mode. When the mode control signal is indicative of the voltage-mode, the method includes connecting a voltage-mode bias sub-circuit to an anode of a reflector-section diode and applying an adjustable bias voltage to bias a diode voltage at the anode of the reflector-section diode. The reflector-section diode is disposed on a shared substrate of a tunable laser. When the mode control signal is indicative of the current-mode, the method includes connecting a current-mode bias sub-circuit to the anode of the reflector-section diode and delivering an adjustable bias current to the anode of the reflector-section diode.

Abstract: A carrier office includes an optical line terminal, a first transmit-erbium-doped fiber amplifier (EDFA), and a second transmit-EDFA. The OLT is configured to transmit first and second optical signals. The first transmit-EDFA is optically coupled to the OLT and a first feeder fiber, and the first feeder fiber is optically coupled to a first remote node (RN). The first transmit-EDFA is operable between a respective enabled state and a respective disabled state. The second transmit-EDFA is optically coupled to the OLT and a second feeder fiber, and the second feeder fiber is optically coupled to a second RN. The second transmit-EDFA is operable between a respective enabled state and a respective disabled state.

Abstract: A method for biasing a tunable laser during burst-on and burst-off states through a common-cathode laser driving circuit includes delivering a bias current to an anode of a gain-section diode having a shared substrate with the laser, and receiving a burst mode signal indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current away from the anode of the gain-section diode. The sink current is less than the bias current delivered to the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the anode of the gain-section diode, and delivering an overshoot current to the anode of the gain-section diode to accelerate heating of the gain-section diode.

Abstract: A remote node includes a first node input, a second node input, and an optical switch. The optical switch includes a first switch input optically coupled to the first node input, a second switch input optically coupled to the second node input, a first switch output switchably coupled to the first switch input or the second switch input, and a second switch output switchably coupled to the first switch input or the second switch input. The remote node includes a photodiode optically coupled to the second switch output, and a capacitor electrically coupled to the photodiode and the optical switch. When the first switch input is switchably coupled to the first switch output, the second switch input is switchably coupled to the second switch output. Light received by the second switch input passes out the second switch output to the photodiode. The photodiode charges the capacitor to a threshold charge.

Abstract: A carrier office includes an optical line terminal, a first transmit-erbium-doped fiber amplifier (EDFA), and a second transmit-EDFA. The OLT is configured to transmit first and second optical signals. The first transmit-EDFA is optically coupled to the OLT and a first feeder fiber, and the first feeder fiber is optically coupled to a first remote node (RN). The first transmit-EDFA is operable between a respective enabled state and a respective disabled state. The second transmit-EDFA is optically coupled to the OLT and a second feeder fiber, and the second feeder fiber is optically coupled to a second RN. The second transmit-EDFA is operable between a respective enabled state and a respective disabled state.

Abstract: A remote node includes a first node input, a second node input, and an optical switch. The optical switch includes a first switch input optically coupled to the first node input, a second switch input optically coupled to the second node input, a first switch output switchably coupled to the first switch input or the second switch input, and a second switch output switchably coupled to the first switch input or the second switch input. The remote node includes a photodiode optically coupled to the second switch output, and a capacitor electrically coupled to the photodiode and the optical switch. When the first switch input is switchably coupled to the first switch output, the second switch input is switchably coupled to the second switch output. Light received by the second switch input passes out the second switch output to the photodiode. The photodiode charges the capacitor to a threshold charge.

Abstract: A system includes a multiplexer having a pass-band and an optical network unit (ONU) optically coupled to the multiplexer. The ONU includes a tunable laser configured to continuously transmit an optical signal to the multiplexer in a burst-on state and a burst-off state. While in the burst-on state, the ONU is configured to tune the tunable laser to transmit the optical signal at a transmit wavelength within the wavelength pass-band of the multiplexer. The multiplexer configured to allow passage therethrough of the optical signal at the transmit wavelength. While in the burst-off state, the ONU is configured to tune the tunable laser to transmit the optical signal at a non-transmit wavelength outside of the wavelength pass-band of the multiplexer. The multiplexer configured to block passage therethrough of the optical signal at the non-transmit wavelength.

Abstract: A method of establishing communication between an optical line terminal and an optical network unit within an optical access network includes receiving a signal indication from an optical transceiver of an optical line terminal. The signal indication includes: (i) a loss-of-signal indication indicating non-receipt of an upstream optical signal from the optical network unit; or (ii) a signal-received indication indicating receipt of the upstream optical signal from the optical network unit. The method includes determining whether the signal indication includes the loss-of-signal indication. When the signal indication includes the loss-of-signal indication, the method includes instructing the optical transceiver to cease signal transmission from the optical transceiver to the optical network unit.

Abstract: A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

Abstract: The communication system has first and second optical systems and an optical feed fiber in communication with the first optical system and arranged to convey a feeder optical signal to the second optical system. The first optical system includes a multiplexer configured to multiplex/demultiplex between a first optical line terminal signal, a second optical line terminal signal, and the feeder optical signal. The feeder optical signal includes the first optical line terminal signal and the second optical line terminal signal. The first optical line terminal signal includes a first upstream free spectral range and a first downstream free spectral range. The second optical line terminal signal includes a second upstream free spectral range and a second downstream free spectral range. The second optical system is in communication with the optical feed fiber and is configured to multiplex and demultiplex between the feeder optical signal and optical network unit signals.

Abstract: A communication system includes a first multiplexer configured to multiplex a first optical line terminal signal having a first multiplexing group and a second optical line terminal signal having a second multiplexing group into a first multiplexed signal. The communication system includes a second multiplexer configured to demultiplex a second multiplexed signal into a third optical line terminal signal having the first multiplexing group and a fourth optical line terminal signal having the second multiplexing group. Moreover, the communication system includes a third multiplexer optically connected with the first multiplexer and the second multiplexer, the third multiplexer configured to multiplex/demultiplex between a feeder optical signal and the first and second multiplexed signals. The first and second optical line terminal signals include a legacy upstream free spectral range, and the third and fourth optical line terminal signals include a legacy downstream free spectral range.

Abstract: A communication system includes a first multiplexer configured to multiplex a first optical line terminal signal having a first multiplexing group and a second optical line terminal signal having a second multiplexing group into a first multiplexed signal. The communication system includes a second multiplexer configured to demultiplex a second multiplexed signal into a third optical line terminal signal having the first multiplexing group and a fourth optical line terminal signal having the second multiplexing group. Moreover, the communication system includes a third multiplexer optically connected with the first multiplexer and the second multiplexer, the third multiplexer configured to multiplex/demultiplex between a feeder optical signal and the first and second multiplexed signals. The first and second optical line terminal signals include a legacy upstream free spectral range, and the third and fourth optical line terminal signals include a legacy downstream free spectral range.

Abstract: A method of calibrating a tunable laser includes shifting a filter output peak defined by a tunable optical feedback filter of the tunable laser in an optical spectral domain to align with a target etalon output peak of a plurality of spaced etalon output peaks defined by an etalon of the tunable laser. The method also includes shifting a cavity frequency grid defined by cavity modes of the tunable laser to align a target cavity mode of the cavity frequency grid with the filter output peak and shifting the spaced output peaks defined by the etalon to align a target etalon output peak with a target wavelength of an output wavelength grid. The method includes modifying a bias current and a modulation current of a gain section of the tunable laser to achieve a defined output modulation amplitude and a defined extinction ratio.

Abstract: The communication system has first and second optical systems and an optical feed fiber in communication with the first optical system and arranged to convey a feeder optical signal to the second optical system. The first optical system includes a multiplexer configured to multiplex/demultiplex between a first optical line terminal signal, a second optical line terminal signal, and the feeder optical signal. The feeder optical signal includes the first optical line terminal signal and the second optical line terminal signal. The first optical line terminal signal includes a first upstream free spectral range and a first downstream free spectral range. The second optical line terminal signal includes a second upstream free spectral range and a second downstream free spectral range. The second optical system is in communication with the optical feed fiber and is configured to multiplex and demultiplex between the feeder optical signal and optical network unit signals.

Abstract: A method of processing optical signals in a passive optical network includes receiving a first signal in a first optical spectrum, and receiving a second signal in a second optical spectrum. The second optical spectrum is different from the first optical spectrum. The method also includes multiplexing the first and second signals into a first multiplexed signal and outputting the first multiplexed signal. The method also includes receiving a second multiplexed signal, and demultiplexing the second multiplexed signal into a third signal and a fourth signal. The third signal is in the second optical spectrum and the fourth signal is in the first optical spectrum. The method also includes outputting the third and fourth signals.

Abstract: A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

Abstract: The communication system has first and second optical systems and an optical feed fiber in communication with the first optical system and arranged to convey a feeder optical signal to the second optical system. The first optical system includes a multiplexer configured to multiplex/demultiplex between a first optical line terminal signal, a second optical line terminal signal, and the feeder optical signal. The feeder optical signal includes the first optical line terminal signal and the second optical line terminal signal. The first optical line terminal signal includes a first upstream free spectral range and a first downstream free spectral range. The second optical line terminal signal includes a second upstream free spectral range and a second downstream free spectral range. The second optical system is in communication with the optical feed fiber and is configured to multiplex and demultiplex between the feeder optical signal and optical network unit signals.

Abstract: A communication system includes a first multiplexer configured to multiplex a first optical line terminal signal having a first multiplexing group and a second optical line terminal signal having a second multiplexing group into a first multiplexed signal. The communication system includes a second multiplexer configured to demultiplex a second multiplexed signal into a third optical line terminal signal having the first multiplexing group and a fourth optical line terminal signal having the second multiplexing group. Moreover, the communication system includes a third multiplexer optically connected with the first multiplexer and the second multiplexer, the third multiplexer configured to multiplex/demultiplex between a feeder optical signal and the first and second multiplexed signals. The first and second optical line terminal signals include a legacy upstream free spectral range, and the third and fourth optical line terminal signals include a legacy downstream free spectral range.

Abstract: A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.