Abstract: To detect deterioration of an SOA and perform feedback control to keep light intensity of output light constant in a configuration in which a DFB laser, an EA modulator, and the SOA are monolithically integrated. A semiconductor optical integrated element includes: a DFB laser that outputs continuous light; an EA modulator that modulates the continuous light; a first multimode interference coupler that inputs the modulated light from a first input port, divides the modulated light, and outputs the divided modulated light from two or more output ports; semiconductor optical amplifiers that are connected to respective output ports of the first multimode interference coupler and amplify each of the divided modulated light; a second multimode interference coupler that has input ports connected to respective outputs of the semiconductor optical amplifiers, multiplexes the amplified modulated light, and outputs the multiplexed modulated light from a first output port; and a monitoring waveguide.

Abstract: A wireless communication node on the multi-hop wireless network has a control message exchanger for exchanging control messages with peripheral nodes to determine neighbor nodes whose information should be registered in a neighbor node information storage; a timing adjuster for adjusting, depending on a connective state of the wireless communication node in the network, a timing at which a first control message is sent back in response to a second control message arriving from other wireless communication nodes; and a registered node determiner for primarily referencing the order of arrival of a first control message from the other wireless communication node to determining neighbor nodes whose information should be registered in the neighbor node information storage.

Abstract: A wireless communication node on the multi-hop wireless network has a control message exchanger for exchanging control messages with peripheral nodes to determine neighbor nodes whose information should be registered in a neighbor node information storage; a timing adjuster for adjusting, depending on a connective state of the wireless communication node in the network, a timing at which a first control message is sent back in response to a second control message arriving from other wireless communication nodes; and a registered node determiner for primarily referencing the order of arrival of a first control message from the other wireless communication node to determining neighbor nodes whose information should be registered in the neighbor node information storage.