Abstract: Disclosed is a bi-directional optical-amplifier module including first through fourth optical amplifiers, a mid-stage device for performing a desired signal processing for an upward or downward optical signal passing therethrough, a first optical-signal-path-setting device for supplying an optical signal inputted to a first input/output terminal of the bi-directional optical-amplifier module while outputting an optical signal outputted from the fourth optical amplifier to the first input/output terminal, a second optical-signal-path-setting device for supplying an optical signal inputted to a second input/output terminal of the bi-directional optical-amplifier module while outputting an optical signal outputted from the third optical amplifier to the second input/output terminal, a third optical-signal-path-setting device for outputting an optical signal outputted from the first optical amplifier to a first input/output terminal of the mid-stage device while supplying an optical signal outputted from the firs

Abstract: The present invention relates to a bidirectional add/drop multiplexer (BADM) and a bidirectional add/drop amplifier (BADA) module. The present invention includes an N×N arrayed waveguide grating router (AWGR), two optical circulators, two wavelength selective couplers, two optical isolators, and a mid-stage device. The mid-stage device comprises a means for compensating the chromatic dispersion of the optical fibers, a means for flattening the spectral response of the optical amplifiers, a means for suppressing the accumulation of the ASE noise or a combination of these means.

Abstract: The present invention discloses a wide band optical amplifier with a common mid-stage device. In the wide band optical amplifier according to the present invention, the signals that enter the amplifier are first split into a couple of sub-band signals. The sub-band signals are amplified independently at different optical amplification sections, but they share a common mid-stage device, which reduces the complexity and the cost of the amplifier. The sub-band signals propagate count-directionally in the common mid-stages device to reduce the nonlinear interactions between the signals in different sub-bands. A wide band optical amplifier incorporating a common mid-stage device with directionality is also disclosed.

Abstract: The present invention relates to an automatic retrieval method of a wavelength-division multiplexed (WDM) ring network to the normal state after recovery of a failure. More specifically, the present invention relates to an automatic retrieval method of a WDM ring network to the normal state after recovery of a failure by inducing a lasing by making the gain of the closed loop larger than 1 using the fact that the recovered section in the ring network forms a closed loop immediately after the recovery of the failure.

Abstract: The present invention relates to a wavelength-tunable light source whose output wavelength can be externally controlled and a wavelength-division multiplexed transmission system using the source.

Abstract: This invention relates to a multicast-capable optical cross-connect with layered modularity. Due to its layered modularity, this invention can be applied to many differently structured networks and provides easier maintenance than conventional optical cross-connects and efficient preparation for network evolution or node upgrade. By exploiting its simple elementary switches, multicast-capable optical cross-connect with layered modularity minimizes the switching time. For a given node, M input fiber ports supply multiplexed optical signals from other nodes in the network and m input fiber ports supply multiplexed optical signals generated from the node. M+m 1×M optical power splitters 311, 312, 313, 314, 315 distribute multiplexed input signals. A drop link module 331 selects signals to be dropped at the node where the optical cross-connect is installed. M transmission link modules 321, 322, 323 select signals to be transmitted to other nodes out of input signals.

Abstract: The present invention discloses a bi-directional add/drop multiplexer (BADM) and a bi-directional add/drop amplifier (BADA) module which add/drop wavelength-interleaved counter-propagating signals. The mid-stage device in the BADM and the BADA module is shared by the counter-propagating signals.

Abstract: The present invention discloses a wide band optical amplifier with a common mid-stage device. In the wide band optical amplifier according to the present invention, the signals that enter the amplifier are first split into a couple of sub-band signals. The sub-band signals are amplified independently at different optical amplification sections, but they share a common mid-stage device, which reduces the complexity and the cost of the amplifier. The sub-band signals propagate count-directionally in the common mid-stages device to reduce the nonlinear interactions between the signals in different sub-bands. A wide band optical amplifier incorporating a common mid-stage device with directionality is also disclosed.

Abstract: Disclosed is a bidirectional optical-amplifier module including first through fourth optical amplifiers, a mid-stage device for performing a desired signal processing for an upward or downward optical signal passing therethrough, a first optical-signal-path-setting device for supplying an optical signal inputted to a first input/output terminal of the bi-directional optical-amplifier module while outputting an optical signal outputted from the fourth optical amplifier to the first input/output terminal, a second optical-signal-path-setting device for supplying an optical signal inputted to a second input/output terminal of the bi-directional optical-amplifier module while outputting an optical signal outputted from the third optical amplifier to the second input/output terminal, a third optical-signal-path-setting device for outputting an optical signal outputted from the first optical amplifier to a first input/output terminal of the mid-stage device while supplying an optical signal outputted from the first

Abstract: The present invention discloses a bidirectional add/drop multiplexer (BADM) and a bidirectional add/drop amplifier (BADA) module which add/drop counter-propagating signals in different wavelength bands. The mid-stage device in the BADM and the BADA module is shared by the counter-propagating signals.

Abstract: The present invention relates to a 4-port wavelength selective router and the add/drop multiplexer using the above router. More particularly, it relates to a 4-port wavelength selective router that can effectively routes counter-propagating signals while suppressing multiple reflections generated in the bidirectional transmission systems and networks.

Abstract: The present invention disclosure a multi-stage bidirectional optical amplifier that amplifies counter-propagating signals at the same time. The multi-stage bidirectional optical amplifier in accordance with the present invention comprises two single-stage bidirectional optical amplifiers(30a, 30b), two multiple reflection suppression means(28a, 28b) and a mid-stage component(42).

Abstract: The present invention relates to an apparatus and a method for a Non-Reciprocal Optical Wavelength Filter (NRWF) suitable for bidirectional optical transmissions, communications, and amplifiers.

Abstract: The present invention relates to an automatic retrieval method of a wavelength-division multiplexed (WDM) ring network to the normal state after recovery of a failure. More specifically, the present invention relates to an automatic retrieval method of a WDM ring network to the normal state after recovery of a failure by inducing a lasing by making the gain of the closed loop larger than 1 using the fact that the recovered section in the ring network forms a closed loop immediately after the recovery of the failure.

Abstract: The present invention discloses a bidirectional add/drop multiplexer (BADM) and a bidirectional add/drop amplifier (BADA) module which add/drop wavelength-interleaved counter-propagating signals. The mid-stage device in the BADM and the BADA module is shared by the counter-propagating signals.

Abstract: The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light.