A tunable filter with a wide free spectral range is provided, having a first collimator, and a second collimator, and a mirror or Bragg reflector interposed between the first and second collimators. A resonance cavity is defined in the space between the Bragg reflector and the second collimator that is able to modulate the wavelength of a light beam passing through the filter. The variable wavelength tunable filter is able to provide better optical performance and stability and a simplified construction of the resonance cavity as compared with direct fiber couplings and traditional tunable filters.