Tunable resonator having a movable phase shifter

A tunable resonator comprising:

• a non-continuous waveguide having a resonance, the waveguide having first and second confrontingly opposite end faces between which is defined a region, a continuous optical path being defined through said waveguide, including across said region;
• and
• a phase shifter selectively movable in said region into and out of said optical path and introducing a phase shift in an optical signal propagating through said waveguide and along said optical path changing the resonance of the non-continuous waveguide when said phase shifter is in said optical path;
• the phase shifter being a phase shift element through which a phase shift may be introduced in the optical signal when said phase shift element is in said region;
• a link connected to an end of said phase shift element;
• and an actuator connected to said link such that movement of said actuator will cause movement of said phase shift element into and out of said region.

A method of tuning to a particular resonant wavelength an optical resonator having a non-continuous waveguide having first and second confrontingly opposite end faces between which is defined a region and having a continuous optical path defined through the waveguide, said method comprising the steps of:

• providing a phase shifter in the region between the first and second end faces;
• by providing a phase shift element through which a phase shift may be introduced in the optical signal when the phase shift element is in the region;
• providing a link connected to an end of the phase shift element;
• providing an actuator connected to the link such that movement of the actuator will cause movement of the phase shift element into and out of the region;
• and
• positioning the phase shifter so as to introduce a phase shift in an optical signal propagating through the waveguide and along the optical path.