Micro-optics photonic bandgap fiber coupler

A resonator sensing device comprising:

• a photonic bandgap resonator fiber having a first end and a second end;
• a first graded index (GRIN) lens;
• a second graded index (GRIN) lens;
• at least one microlens;
• and
• at least one source fiber,
• wherein the first GRIN lens includes a surface angled to allow light emanated from the at least one microlens and the at least source fiber to reflect into the first end of the resonator fiber,
• wherein the second GRIN lens is positioned to allow a portion of light emanated from the second end of the resonator fiber to pass through to said first GRIN lens and be received by the first end of the resonator fiber, and to allow a portion of the light emanated from the second end of the resonator fiber to be reflected, as at least one sensing light signal, into the at least one source fiber via the at least one microlens.

A method for making resonator sensing device, the method comprising:

• placing an end of a source fiber into a jig, wherein the source fiber being previously configured to receive light from a light source and deliver light to a sensor;
• placing a mirror on the jig at an expected location for a graded index (GRIN) lens;
• placing a microlens on the jig between the source fiber end and the mirror;
• placing one end of a photonic bandgap resonator fiber on the jig at a predefined angular relationship from the placed end of the source fiber and the microlens relative to the mirror;
• sending a light signal out of the end of the resonator fiber, off the mirror, into the end of the source fiber via the microlens;
• sensing the sent light signal at the sensor;
• and
• adjusting a location on the jig of at least one of the end of a source fiber, the microlens, or the resonator fiber based on the sensed light signal.