For a laser diode (LD) pumped solid-state laser system using high power LD arrays, compact optical sensors of high speed, high response, low noise and low cost are needed. We constructed optical probes using Ge avalanche photo-diode (APD) and Si-APD for the wavelength region of 0.3-1.6μm. To measure the intensity distribution of laser beams, spectral distribution, and wavelength shift of LD arrays, we used a CCD linear image sensor and a polychromator which were designed and constructed.