Ultrashort pulse OPO ring laser

Summary form only given. A ring cavity optical parametric oscillator (OPO) can be pumped synchronously in one direction by a Ti:sapphire fs laser. It can be operated in the other direction by sending the pump pulses from the opposite direction. The crossing point between the two pulse trains of the OPO can be adjusted by introducing a delay line in one of the pump beams. Because the delay is adjusted in such a manner as to prevent crossing of the two intracavity counter-propagating pulses near any optical component susceptible to scatter, the signal beams that circulate in opposite direction inside the OPO resonator are uncorrelated. Therefore, this laser is susceptible to be an ideal laser gyro without dead band. Furthermore, there is no gain competition between the counter-rotating modes, since the lifetime of the gain in the OPO crystal is equal to the pump pulse duration. We present an experimental investigation of the operation of such a synchronously pumped ring laser and the beat note characteristics.