In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

A system and method for securing communication over an optical fiber are disclosed. The system includes a transmit spatial multiplexer configured to couple a plurality of optical signals into respective ones of a plurality of spatial paths of an optical fiber, each of the spatial paths being able to carry an optical signal; wherein at least one of the plurality of optical signals is an optically modulated version of a desired sequence of information that is intended to be transferred over the optical fiber; and wherein at least one of the plurality of optical signals is an optical chaff signal; whereby a tap along the fiber cannot determine the transmitted desired sequence of information.

A method for securing communication over an optical fiber, comprising: supplying an optically modulated version of a desired sequence of information that is intended to be transferred over a multicore optical fiber to a first core of the multicore optical fiber; and supplying an unmodulated optical chaff signal to a second core of the multicore optical fiber that is spatially distinct from the first core; wherein the fiber is adapted to transport the optical chaff signal from a first end thereof to a second end thereof unmodified in the second core; and wherein the fiber is adapted to transport the optically modulated version of a desired sequence of information from the first end of the fiber to the second end of the fiber unmodified in the first core and independent of the chaff signal in the second core unless there is a tap of the fiber.

Apparatuses and methods for wavelength selective switching and optical performance monitoring are provided. Spatially separated wavelength channels of an optical signal are directed onto an optical deflector array. The optical deflector array is configured so that each wavelength channel is incident on a respective region of the optical deflector array. The optical deflector array is controlled so that, for one or more of the wavelength channels: i) a first portion of the region of the optical deflector array upon which the wavelength channel is incident is configured to steer a first portion of the wavelength channel toward a switching output port; and ii) a second portion of the region is configured to steer a second portion of the wavelength channel toward a monitoring output port.

In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

A wavelength selective switch is configured to demultiplex WDM light input from an input side for each wavelength, to supply the demultiplexed signal lights to deflectors corresponding to the demultiplexed wavelength, and to control the deflector to selectively output the demultiplexed signal lights to an output side, in which monitor light having at least a wavelength included in the WDM light is input to the wavelength selective switch from the output side of the wavelength selective switch, and the monitor light input from the output side of the wavelength selective switch is monitored, the monitor light being propagated in a direction opposite to a propagation direction of the signal lights each having the demultiplexed wavelength in the wavelength selective switch and being output to the input side of the wavelength selective switch.

A bi-directional multiplexer/demultiplexer comprises a common port, an upgrade (UPG) port, a plurality of input/output ports, a plurality of wavelength division multiplexing (WDM) filters arranged in a zig-zag fashion, and a single bi-directional tap. The single bi-directional tap directs a tapped signal to a demultiplexing tap port in demultiplexing mode and a multiplexing tap port in multiplexing mode. The bi-directional tap may be a thin-film tap filter.

A method for securing communication over an optical fiber, comprising: supplying an optically modulated version of a desired sequence of information that is intended to be transferred over a multicore optical fiber to a first core of the multicore optical fiber; and supplying an unmodulated optical chaff signal to a second core of the multicore optical fiber that is spatially distinct from the first core; wherein the fiber is adapted to transport the optical chaff signal from a first end thereof to a second end thereof unmodified in the second core; and wherein the fiber is adapted to transport the optically modulated version of a desired sequence of information from the first end of the fiber to the second end of the fiber unmodified in the first core and independent of the chaff signal in the second core unless there is a tap of the fiber.