Single-pass gain in a chirped quasi-phase-matched optical parametric oscillator

In this letter, the single-pass gain of a quasi-phase-matched optical parametric oscillator with chirped poling is calculated. Specifically, the single-pass gain from optical parametric oscillators containing a z(n) chirped profile of their periodically poled grating wavelength is derived. Using the calculated gain, the parametric oscillator threshold is determined. Both the gain and threshold condition for a chirped device contain an increased power scaling in the pump intensity over a uniformly poled device due to the pump power dependence in the interaction length. The chirped poling structure exhibits a lower gain, a higher threshold, and a larger bandwidth at threshold than uniformly chirped devices with the same overall crystal length. (C) 2003 American Institute of Physics.