Methods and apparatus related to a distal end of a side-fire optical fiber having multiple capillary components

An apparatus, comprising:

• a side-fire laser fiber including a first capillary extending along a longitudinal axis and having an open distal end and an optical fiber, the open distal end of the first capillary having a flat distal end face perpendicular to the longitudinal axis, the first capillary being heat-fused to an outer surface of the optical fiber, the optical fiber having an angled distal end surface being within a plane non-normal to a longitudinal centerline of the optical fiber and configured to reflect laser radiation propagated along a longitudinal axis of a distal end portion of the optical fiber in a lateral direction through the first capillary and the second capillary;
• a second capillary being heat-fused to an outer surface of the first capillary and having an open flat distal end face, the distal end face of the first capillary and the distal end face of the second capillary each extending distally beyond the distal end surface of the laser fiber;
• and
• an outer cover cap coupled to and disposed outside the second capillary, the outer cover having a side opening and a portion distal of the side opening that surrounds the second capillary, wherein the outer cover cap includes an internal planar surface abutting the distal end face of the first capillary and the distal end face of the second capillary.

An apparatus, comprising:

• a first capillary extending along a longitudinal axis and having an inner surface and an open distal end, the open distal end of the first capillary having a flat distal end face perpendicular to the longitudinal axis;
• an optical fiber disposed inside of the first capillary, the inner surface of the first capillary being heat-fused with an outer surface of the optical fiber, the optical fiber having an angled distal end surface configured to reflect electromagnetic radiation propagated along a longitudinal axis of a distal end portion of the optical fiber in a lateral direction through the inner surface of the first capillary;
• a second capillary disposed outside of the first capillary component, the second capillary having a tubular construction open at a proximal and distal end, the distal end of the second capillary having an open flat distal end face, wherein the distal end face of the first capillary and the distal end face of the second capillary extend distally beyond the distal end surface of the optical fiber;
• and
• an outer cover cap coupled to and disposed outside the second capillary, wherein the outer cover cap includes an internal planar surface abutting the distal end face of the first capillary and the distal end face of the second capillary.