Fabrication of Polarization-Maintaining Photonic Crystal Fiber Coupler with Air Hole State Control Using CO2 Laser Irradiation Technique. - Hirohisa Yokota; Yusuke Ito; Hiroki Kawashiri; Hideyuki Kiue; Hideo Tobita; Yoh Imai; Yutaka Sasaki (IEICE Trans. Electron., 2012)