Self-Routing Wavelength Switch

A new approach to implementing self-routing switch for wavelength-division multiplexing (WDM) fiber-optic network applications is proposed. This switch is based on an innovative wavelength router that divides the incident optical signal into separated spectral bands at two output ports. The wavelength router is insensitive to the polarization state of light signals, and has a low side-lobe crosstalk and an excellent temperature stability. The switching function of the router is performed by high-speed ferroelectric liquid-crystal devices, so that the reconfiguration speed can be as short as 35 microseconds. A distinctive feature of this liquid-crystal device is that a binary operation condition can be arranged so that no electric power is required on both switch states, and only extremely small amount energy (100 pJ) is needed for each switching transition. This device technology enables communication in a remotely distributed network where power supply is critical. An out-of-band signaling architecture is proposed to transmit the header information at 1310nm, while dense WDM channels at 1550nm window are utilized for payloads. When remote power is unavailable, pipelining the 1310nm optical power can be adopted to actuate this low power-consumption switching nodes.