A new Al-LiTaO3-ITO infrared detecting structure on quartz glass substrate with a micro bridge is designed. Under the response/reference dual-element configuration, undesirable signals, caused by vibration, ambient temperature change and sunlight, are cancelled out at the input of the preamplifier circuit. The LiTaO3 thin film was chosen as infrared sensing film and prepared by a sol-gel process using lithium acetate and tantalum ethoxide as starting materials. The fabrication process of device is discussed in details. The dielectric properties of the sol-gel prepared LiTaO3 thin film were measured using evaporated Al dots as front electrode and the ITO substrate as bottom electrode. The dielectric coefficient of LiTaO3 thin film is about 53.28 at 1kHz. The dielectric coefficient and the dielectric loss appear falling tendency within the measured frequency range from 40 Hz to 10K Hz. Voltage response experimental results of the LiTaO3 device is obtained by an infrared device measurement system and indicate that the response voltage peak is about 9685V/W at 75Hz, and the specific detectivity D* peak of the device is near 6.12×108cmHz1/2W-1 from 70Hz to100Hz.

The mechanism is put forward that the axial magnetic field parallel to the wave-guide of the LiNbO3 modulator may affect the half-wave voltage. The electric field acting on the electrode of the LiNbO3 crystal may bring linear birefringence to the polarized light propagating in LiNbO3 modulator, and the axial magnetic field may bring circular birefringence to it, too. So the acting result of the two types of birefringence makes the half-wave voltage vary with the magnetic field. The maths model about the variance that the half-wave voltage varies with the magnetic induction outside is set up. The simulation result and the examination result show that as to the light source whose wavelength is 1.30μm, when the magnetic induction changes about 20 Tesla, the half-wave voltage of LiNbO3 modulator may decrease 2.13%.