Wavelength detection using optical fiber speckle patterns

If the wavelength of injected light changes, the phase of the field also changes. Then the intensity distribution also changes. This property has been introduced to the application of holographic recording to reduce crosstalk and enhance hologram density. We can use this property in the sensing of wavelength change in an optical fiber sensing system. In the experiment, the laser diode was used as a light source. The tuning of wavelength was performed by controlling the operating temperature of the laser diode.