Phase change recording with an optically switched laser (OSL) head is realised for the first time. This head consists of a 1.3µm wavelength laser diode monolithically integrated with a photodetector (LD-PD) and a flying slider. The lensless OSL head has a minimum power of 18 mW (1 MHz) for writing information on a 1200 rpm, 130 mm diameter, SbTe based alloy disk. The bit shape and crystalized level are uniform and the readout signals are of high quality.

Optical waveguide polarizers are realized by three dimensional polymer thin film waveguides with a-Si: H film clad. It has a low index buffer layer between the waveguide and a-Si: H film clad. It is experimentally found that a high extinction ratio for either TE or TM mode pass polarizer can be obtained by changing the hickness of the a-Si: H film clad.