High Electro-Optic Sensitivity (r33) Polymers: They Are Not Just for Low Voltage Modulators Any More

Abstract

To achieve gain ≥0 dB in an external modulation analogue optical link with modest laser power (∼10 mW), the external modulator needs to have an on−off voltage (Vπ) of ∼ 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 r33 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 r33 material for? We will show that there are many uses to which a larger r33 material can be put, but that, contrary to present perception, even lower Vπ is not one of them. The paper concludes by discussing one of the uses for a larger r33: a linearized modulator.