Phase shifter is an important part of optical waveguide circuits as used in interferometer. However, it is not always easy to generate a large phase shift in a small region. Here, a variable phase-shifter operating as delay-line of silicon waveguide was designed and fabricated by silicon micromachining. The proposed phase-shifter consists of a freestanding submicron-wide silicon waveguide with two waveguide couplers and an ultrasmall silicon comb-drive actuator. The position of the freestanding waveguide is moved by the actuator to vary the total optical path. Phaseshift was measured in a Mach-Zehnder interferometer to be 3.0π at the displacement of 1.0 urn at the voltage of 31V. The dimension of the fabricated device is 50μm wide and 85μm long.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics