A switchable optical amplifier includes: a first optical amplifier; a second optical amplifier; and an optical switch which includes first and second input ports and first and second output ports, the optical switch that switches between a first connection state where the first input port and the first output port are in an optical connection and the second input port and the second output port are in a no optical connection and a second connection state where the first input port and the second output port are in an optical connection and the second input port and the first output port are in an optical connection, wherein an output of the first optical amplifier is optically coupled to the first input port of the optical switch, an input of the second optical amplifier is optically coupled to the second output port of the optical switch.

An optical amplifier (1), and a related optical amplification method, comprising an optical path (2) having an input end (3) and an output end (4), a first erbium doped optical fiber (5) placed along the optical path, a first gain flatting filter (6) placed along the optical path downstream the first erbium doped optical fiber, a second erbium doped optical fiber (7) placed along the optical path downstream the first gain flatting filter, a second gain flatting filter (8) placed along the optical path downstream the second erbium doped optical fiber, a third erbium doped optical fiber (9) placed along the optical path downstream the second gain flatting filter, and an optical pump (10) optically coupled to the optical path so as to optically pump at least the first and the third erbium doped optical fiber.

An amplifier, a circuit, and an optical communication system are provided. The disclosed amplifier may include a single-to-differential variable gain amplifier having a variable resistor switch that substantially always operates in a triode region at all time. Said another way, the resistor switch is configured to operate in a triode region regardless of whether or not a first portion of an input signal to the variable gain amplifier is larger than a second portion of the input signal. The disclosed scheme helps to keep the variable resistor switch in the triode region in all cases of operation, thereby maintaining the linearity condition and reducing distortion in the variable gain amplifier.

Example embodiments of the present invention relate to an optical signal processor comprising of at least one wavelength processing device, a plurality of optical amplifying devices, and a least one field programmable photonic device.

The telecommunications network node linking a metropolitan area network, including at least one optical link connecting the nodes, with at least one access network, includes an electronic card that enables the aggregation of traffic from multiple access networks, a transmitter capable of receiving an electrical signal from the electronic card and of transmitting an optical packet to the metropolitan area network, a circulator capable of extracting a stream of multiplexed optical packets from the optical link and of inserting a stream of multiplexed optical packets into the optical link, and a reflective switching matrix receiving a stream of multiplexed optical packets from among which it selects and detects those intended for the access network. The reflective switching matrix includes a POADM optical packet add/drop multiplexer that receives multiplexed optical packets and transmits demultiplexed optical packets, and at least one RSOA reflective semiconductor optical amplifier capable of receiving a demultiplexed optical packet, which includes three sections.