Kentaro IKE1 and Heihachi SATO2

1Japan Air Self-Defense Force, Ichigaya, Tokyo, 162, Japan 2Department of Electrical Engineering, National Defense Academy, Yokosuka, 239 Japan

(Received November 21, 1995; Accepted February 23, 1996)

Combining one stable resonator with a concave mirror and a coupling-hole plane mirror, and another unstable resonator having a concave mirror and a convex mirror, a new hybrid optical resonator type laser has been proposed by overlapping the concave mirror as a common one and fitting the convex mirror exactly to the coupling-hole. Using the ABCD law, the so-called g-parameters are first found for beam confinement. Then, based on the eigen-equation, the field distribution on the plano-convex mirror is obtained with the g-parameters above. Knowing this field distribution results in an effective transmittance _e. Finally, the ratio of the inner convex to outer plane mirror radii can be determined for an optimum coupling in both the limiting cases of homogeneously and inhomogeneously broadened gain media. Some numerical examples will also be given for a CO₂ laser having the proposed hybrid resonator.

Key words: optical resonator, hybrid optical resonator, direct coupling, optical fiber, high power laser