A sensing method for in-situ non-perturbing measurement of characteristics of laser beams at the exit of the laser beam delivery fiber tips include measuring power of a laser beam transmitted through delivery fiber tip in fiber-optics systems. A sensing devices for in-situ non-perturbing sensing and control of multiple characteristics of laser light transmitted through light delivery fiber tips includes a fiber-tip coupler comprised of a shell with enclosed delivery fiber having a specially designed angle-cleaved endcap and one or several tap fibers that are specially arranged and assembled at back side of the endcap and other variations. Methods and system architectures for in-situ non-perturbing control of characteristics of laser beams at the exit of the laser beam delivery fiber tips include fiber-tip couplers and sensing modules that receive laser light from tap fibers, and systems for optical processing to enhance light characteristics suitable for in-situ measurement.