Abstract
We present an optomechanical method to tune phase and group birefringence in parallel silicon strip waveguides. We first calculate the deformation of suspended, parallel strip waveguides due to optical forces. We optimize the frequency and polarization of the pump light to obtain a 9 nm deformation for an optical power of 20 mW. Widely tunable phase and group birefringence can be achieved by varying the pump power, with maximum values of 0.026 and 0.13, respectively. The giant phase birefringence allows linear to circular polarization conversion within 30 microm for a pump power of 67 mW. The group birefringence gives a tunable differential group delay of 6fs between orthogonal polarizations. We also evaluate the tuning performance of waveguides with different cross sections.
Highlights
Optical forces have recently been investigated as a way of repositioning microphotonic elements such as waveguides [1,2,3,4] and microcavities [5,6,7,8]
We present an optomechanically-controlled system which resembles a suspended one-slot waveguide with an adjustable slot width that depends on the optical force and exhibits highly tunable birefringence
We present an optomechanically-controlled system which resembles a suspended one-slot waveguide with adjustable slot width depending on the optical force
Summary
Optical forces have recently been investigated as a way of repositioning microphotonic elements such as waveguides [1,2,3,4] and microcavities [5,6,7,8]. We present an optomechanically-controlled system which resembles a suspended one-slot waveguide with an adjustable slot width that depends on the optical force and exhibits highly tunable birefringence. Kumar et al [21] varied the air-core thickness in a 3D hollow waveguide via MEMS acutation to offer a large birefringence of 0.012 with a tuning range of 0.01 This result points to the relatively large changes in birefringence that can be achieved using mechanical motion to physically change the waveguide geometry. The force arising from the evanescent coupling between the modes of the two waveguides deforms both waveguides, changing the air-slot width. Such behavior results in all-optically adjustable giant birefringence. We explore the applications of the two-waveguide system for tunable linear-to-circular polarization conversion and polarization-dependent delay
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
