Polarization-independent double phase conjugate mirror

We present a polarization-independent double phase conjugate mirror (DPCM) working at telecommunication wavelength 1.32 μm. To do this, InP:Fe photorefractive crystals are used. A 2Z-DPCM configuration is realized in order to eliminate conical diffraction and to reduce the instabilities. With this device, the conjugation efficiency remains almost unchanged when the polarization state of the incident beam varies. Dynamic measurements demonstrate that the device is well-adapted to relatively slow variations of the polarization, induced by thermal variations for example.