Method and arrangement in connection with optical bragg-reflectors

An arrangement for analyzing the power spectrum of a light signal, comprising:

• a light-guiding structure, having an input end and an output end;
• a chirped Bragg-reflector in said light-guiding structure, which chirped Bragg-reflector is provided between the input end and the output end;
• an acoustic actuator connected to said light-guiding structure;
• and
• a detector provided at the output end of said light-guiding structure, said detector delivering a detector output signal,
• wherein the input end of said light-guiding structure is arranged to receive the light signal to be analyzed, said acoustic actuator is operative to emit a longitudinal acoustic pulse for propagation along the light-guiding structure, and said detector is operative to detect the light thus transmitted through said Bragg-reflector and to provide a detector output signal associated with the power spectrum of said light signal.

A method of analyzing the power spectrum of a light signal, comprising the steps of:

• directing the light signal to be analyzed into a light-guiding structure incorporating a chirped Bragg-reflector;
• sending a longitudinal acoustic pulse into said light-guiding structure for propagation along the same, the acoustic pulse being such that, for each location of said acoustic pulse in said Bragg-reflector, the reflectivity for a wavelength associated with said location in said Bragg-reflector is altered;
• monitoring the light thus transmitted through said light-guiding structure;
• and
• analyzing the monitored light, in order to obtain a power spectrum analysis of the light signal directed into the light-guiding structure.