Tunable Parametric Oscillator Using a Guided Wave Structure

A proposed tunable optical parametric oscillator in a guided wave structure consisting of a thin nonlinear slab asymmetrically sandwiched by two linear dielectrics is treated theoretically. The two linear dielectrics have smaller indices of refraction than the nonlinear dielectric, and the oscillator frequency is tunable by changing the refractive index of one of the linear dielectrics. For a GaAs nonlinear film sandwiched by Irtran 3 or Sapphire and liquid, calculations show that the oscillation frequency can be tuned over ±35% of the subharmonic frequency of a 1.06µ pump as the refractive index of the liquid is varied from 1.25 to 1.6. For reasonable parameters, the threshold power is estimated to be 7 milliwatts. The phase matching conditions and oscillation characteristics for parametric interaction in a guided wave structure are derived and discussed.