High electro-optic sensitivity (r33) polymers:: They are not just for low voltage modulators any more

To achieve gain greater than or equal to 0 dB in an external modulation analogue optical link with modest laser power (similar to10 mW), the external modulator needs to have an on-off voltage (V-pi) of similar to 0.3 V, which is more than a factor of 10 smaller than the on-off voltages of most commercially available modulators. Polymeric materials, in which the electrooptic tensor r(33) has been engineered to have a very large magnitude ( > 100 pm/V), enable external modulator designers to meet this goal, because the modulator's on-off voltage is inversely proportional to this tensor magnitude. Now that polymer materials have surpassed 100 pm/V, the natural question is: what do we need even higher r(33) material for? We will show that there are many uses to which a larger r(33) material can be put, but that, contrary to present perception, even lower V-pi is not one of them. The paper concludes by discussing one of the uses for a larger r(33): a linearized modulator.