Microstructured fiber end surface grating for coarse WDM signal monitoring

We propose a new in-line wavelength measurement technique based on one-dimensional fiber end-surface grating for monitoring signals in coarse wavelength-division multiplexing. The fiber end-surface grating was fabricated with fenitosecond laser pulses by inscribing microstructure on the cleaved surface of a thermally expanded core fiber and the diffracted beam patterns from the fiber end-surface grating were. experimentally analyzed according to the wavelength of input light.