Patent ID: 7065264
Filing Date: 2006-06-20
Classification: G02F,H01S

Abstract:
1. An optic system including an integrated variable optical attenuating device for attenuating an input optical signal, the integrated optical variable attenuating device including a first electrically controllable attenuating element and a second electrically controllable attenuating element cascaded together, the first attenuating element having a first range of optical attenuation smaller than a second range of optical attenuation of the second attenuating element but requiring less input power than the second attenuating element to switch between levels of attenuation within the first range of attenuation, and wherein the optic system further includes electrical circuitry for controlling the first and second attenuating elements in coordination with one another so as to achieve the desired level of total attenuation of the optical signal, wherein the first attenuating element is electrically switchable between a first, low level of attenuation and a second, high level of attenuation, and the second attenuating element is electrically controllable over a range of attenuation levels between the first and second levels of attenuation, and wherein the electrical circuitry is provided for switching the first attenuating element between the first and second levels of attenuation and for controlling the second attenuating element over a range of attenuation levels between the first and second levels of attenuation in coordination with each other in accordance with the desired level of total attenuation, and wherein the first and second levels of attenuation are levels of attenuation at which the polarization dependency of the first attenuating element is at a minimum.