Optical Switch - Patents

Patents

A 2011 search on “optical switch” yielded some 8,000 patents, roughly categorized as follows:

• MEMS approaches involving arrays of micromirrors that can deflect an optical signal to the appropriate receiver (e.g., US 6396976 );
• Piezoelectric Beam Steering involving piezoelectric ceramics providing enhanced optical switching characteristics
• Inkjet methods involving the intersection of two waveguides so that light is deflected from one to the other when an inkjet-like bubble is created (e.g., US 6212308 );
• Liquid crystals (e.g., US 4948229 ) that rotate polarized light either 0 degrees or 90 degrees depending on the applied electric field;
• Thermal methods (e.g., US 5037169 ) that vary the refraction index in one leg of an interferometer to switch the signal;
• Nonlinear methods (e.g., US 5319492 ) that vary the diffraction pattern in a medium by taking advantage of the material nonlinear properties to deflect light to the desired receiver;
• Acousto-optic methods that change the refraction index as a result of strain induced by an acoustic field to deflect light (e.g., US 6922498 );
• Amplifiers and attenuators in output fibers that adjust the signal to the digital “0” power range (when the fiber is not switched to) or to the normal power range when it is (e.g., US 7027211 ).