National Institute of Advanced Industrial Science and Technology

Takayuki Kurosu

Shu Namiki

Satoshi Suda

Kiyo Ishii

It is an object to monitor signal flow (optically switched state) in an optical node without using a monitor light. In each of output ports of the optical node, a part of output signals is turned back, and the output signal light is subjected to intensity modulation or phase modulation, assigned port identification information, and allowed to reverse in the optical node. From an input port corresponding to the reversed output signal, a plurality of signals turned back are output. The plurality of signals are appropriately converted into intensity modulation from phase modulation and separated by a device having a spectroscopic function, and identification information is read out based on an intensity of a signal light for each signal, thereby determining an optically switched state to an output port corresponding to the input port.

Optical switch, and optical node monitoring system and monitoring method

In a signal regeneration device in which recovery of a signal quality which has been degraded during transmission in optical communication and extension of a transmission distance are achieved, the most representative method of quantizing an optical phase is a phase sensitive amplifier (PSA) and a technique that utilizes an optical parametric process through use of a highly nonlinear optical medium, but there is a demand for a technique of quantizing an optical phase which is not accompanied with an optical parametric gain, has small-sized elements, is easily integrated, and does not require high power pump light. By a technique of a hybrid optical phase squeezer (HOPS), when a phase of input light is quantized to M levels (M&#x3e;2), phase conjugate light of the input light and (M&#x2212;1)th phase harmonic light of the input light are subjected to power modulation to be coherently added, so that quantization of the optical phase is performed through use of a simple four-wave mixing (FWM) that is not accompanied with the optical parametric gain and a general optical amplifier by using a general nonlinear optical medium such as silicon, and accordingly, a GER of equal to or higher than 30 dB can be obtained, even if a nonlinear optical element having a low nonlinearity is used.

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Ibaraki, Japan

Takayuki Kurosu