Page 266 - Introduction to Information Optics

Exercises

4.8 Find the required length of optical fiber (made of silica glass) in order to
have TT nonlinear phase shift at a control power level of 100 mW at
1.55/(in wavelength.
4.9 The LiNbO 3 crystal has a EO tensor given by

T

12
where for A = 633 nm, T, 3 = 9.6 x 10~ , T, 6.8x10 =30,9x
1-12 12
and T 51 = 32.6 x 10~~ m/V. What is the half-wave electric field
for a LiNb0 3 modulator where light polarizes along the y axis, and the
modulating electric field is applied along the z axis? Assume A = 633 nm
and the length of the modulator L = 4 mm.
4.10 Consider the case described in Problem 9. How large an electric field E z
is required to change the index of refraction by 0.0001?
4.11 The sensitivity of a device is defined as the incremental change of the
output per unit incremental change of the input. Find the sensitivity of
an interferometric EO intensity modulator using the Mach-Zehnder
configuration (Fig. 4.22), if the half-wave voltage is V n = 10 V.
4.12 An optical intensity modulator uses two integrated electro-optic phase
modulators and a 3-dB directional coupler, as shown in Fig. 4.P1. The
input wave is split into two waves of equal amplitudes, each of which is
phase modulated, reflected from a mirror, and phase modulated once

Mirror

Fig. 4.P1.