INTERFERENCE DEVICE OPTICAL CIRCUIT AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To independently adjust an optical path length (phase) to TE polarization and TM polarization. SOLUTION: Thin film heaters 4a and 4b as two kinds of heat-treating regions having different widths W1 and w2 are provided on a waveguide core 2. When the thin film heaters 4a and 4b are electrically energized and heat- treated, a clad layer 3 is changed in quality, stress exerting on the waveguide core 2 is changed and whereby polarization dependence is controlled. Then, TE polarization and TM polarization are made independent and permanent performance refractive index (double refractive index) is controlled by changing the widths of the thin film heaters 4a and 4b and a quantity of energizing. Thus, for example, TE and TM are respectively made to coincide with a phase differenceλ/2 and a phase difference zero.