| 摘要 |
A method of fabricating a switching element (120) or a matrix (50) of switching elements includes providing a waveguide substrate (52; 150; and 198) having at least two waveguides (62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90 and 92; 108, 110, 112 and 114) that intersect at a trench (94; 152 and 154; 200 and 202) such that optical coupling between the waveguides is dependent upon the presence or absence of an index-matching fluid at the intersection of the waveguides with the trench. Fluid is supplied to the trench via a fluid fill-hole (57; 116 and 118; 148 and 188) that extends through a heater substrate (53; 122; and 160) in a direction that is generally perpendicular to a substrate surface on which at least one heater (100 and 102; 132; and 170) is fabricated. In the preferred embodiment, the fluid fill-hole is formed in a step of inductively coupled plasma (ICP) reactive ion etching (RIE). The waveguide substrate having at least two waveguides and the heater substrate having the heaters and the fill-hole are bonded together after the substrates are aligned such that the trench is in fluid communication with at least one fluid fill-hole and is in thermal communication with at least one heater. Optical fibers (96) are then coupled to the waveguides. Preferably, a structurally weakened edge portion (158 and 196) is formed during the ICP RIE step so that the edge portion can be removed after the two substrates are bonded, allowing uninhibited access of the optical fibers to the waveguides. <IMAGE> |
