
498 APPENDIX G
G.7 CHAPTER 7
Problem 7.1: Laser Tuning
Suppose that I place the back mirror of a laser on a piezoelectric transducer that moves the
mirror axially through a distance of 10 μm with an applied voltage of 1 kV, and that the rela-
tionship between position and voltage is linear. The laser has a nominal wavelength of 633 nm.
The cavity length is 20 cm.
7.1a What voltage is required to sweep the cavity through one free spectral range?
Solution:
The easy way to handle this is to note that we have to change the cavity length by half a
wavelength to move the q − 1 mode to where the q mode was. Thus,
V
FSR
= 1000 V
633/2
10, 000
= 31.65 V (G.67)
7.1b