MICROELECTROMECHANICAL SYSTEM (MEMS) DEVICE READOUT WITH OPTICAL DIRECTIONAL COUPLER
FIG4 is a top view of one exemplary embodiment of a MEMS device including two optical directional couplers and two vibrating proof masses according to the embodiments of the present disclosure
FIG4 illustrates another example embodiment of a MEMS device comprising at least one optical directional coupler. MEMS device 400 shown in FIG4, comprises two directional couplers 492 and 494, both of which are used in the process of determining the angular rate of rotation in the MEMS device, by determining positions of vibrating proof masses 415 and 475. For example, FIG4 is one example of MEMS device 400 that uses two directional couplers, each directional coupler having two waveguides. As seen in FIG4, MEMS device 400 includes waveguides 422 and 424 comprised in a first directional coupler 492, and waveguides 462 and 464 comprised in a second directional coupler 496.
view
464
waveguides waveguide
407
electrode
412
photodetectors photodetector
415
vibrating proof mass vibrating proof masses
452
further includes two photodetectors
422
waveguides waveguide
400
MEMS device
414
further includes two photodetectors
476
electrode
494
second directional coupler
465
second light source Light sources
424
waveguides waveguide
454
further includes two photodetectors
425
light source
406
electrode
475
vibrating proof mass vibrating proof masses
150
reference
485
such as central region
['1. A microelectromechanical systems (MEMS) device comprising: an optical directional coupler comprising: at least one light source configured to provide a light beam; at least one substrate; a first waveguide formed on the at least one substrate, the first waveguide having a first end and the second end, wherein the first end of the first waveguide is coupled to the at least one light source, wherein the light beam is introduced into the first end of the first waveguide; a second waveguide formed on the substrate, the second waveguide having a third end and a fourth end, wherein the first waveguide and the second waveguide are positioned adjacent to each other at a central region of the optical directional coupler at a distance such that the light beam is at least partially evanescently coupled between the first waveguide and the second waveguide in the central region when the light beam is introduced into the first end of the first waveguide; a first photodetector coupled to a second end of the first waveguide, wherein the first photodetector is configured to detect a first optical power in the light beam propagating through the first waveguide at the second end; and a second photodetector coupled to a fourth end of the second waveguide, wherein the second photodetector is configured to detect a second optical power in the light beam propagating through the second waveguide at the fourth end; at least one vibrating proof mass positioned adjacent to the optical directional coupler in a first direction from the optical directional coupler, wherein the at least one vibrating proof mass is equidistant from the first waveguide and the second waveguide, wherein when one or more inertial forces are applied to the MEMS device in at least one of the first and a second direction, the at least one vibrating proof mass is configured to move in the first direction; at least one processor coupled to the first photodetector and the second photodetector, wherein the processor is configured to determine the displacement of the at least one proof mass from the optical directional coupler as a function of the first optical power and the second optical power.', '6. The MEMS device of claim 2, wherein the at least one light source comprises: a first light source configured to provide the light beam; and a second light source configured to provide the second light beam.']