He has been part of the international improvised music scene since the early 2000s, performing and recording throughout Latin America, Europe, and the U.S. Kaplan worked with percussionist Diego Chamy and trumpeter Axel Dörner first.

Kaplan's collaborations around that time involved him on tours with Le Quan Ninh, Michel Doneda, Wade Matthews, Bhob Rainey & Greg Kelley (Nmpering), and Ivar Grydeland (Huntsville).

The trio released Silo (Utech Records) the same year and toured Belgium, France, Germany, Netherlands, and England in the winter of 2006, and during late September they traveled through the Midwest, South, and East Coast of the U.S. Kaplan also played extensively with Japanese drummer Tatsuya Nakatani.

Other collaborations included tours and recordings with French clarinetist Xavier Charles, the large improvisation group No Spaghetti Edition Ensamble, dancers Nicole Bindler, Andrea Fernández and Ly Thanh Tiên, and a trumpet piece commissioned by Jennifer Allora & Guillermo Calzadilla for a work entitled "Wake Up" written for the Renaissance Society in Chicago.

Since 2007 he has been working in a duo with Christof Kurzmann (sometimes amplified by Edén Carrasco, John Butcher, George Cremaschi or dancer Nicole Bindler) playing in Argentina, Uruguay, Chile, and Austria.