In this paper, the technology of molecule saturation absorption frequency stabilization of the external cavity laser diodes (ECLD) on 1.5μm which is recently researched is discussed, and it can obtain high ratio of precision. The improved scheme of the servo circuit system of the ECLD’s molecule saturation absorption frequency stabilization is investigated in the paper. The peripheral loop servo circuit system is the key of the frequency stabilization control. The original servo system uses a lot of discrete components. Its structure is intricate and the performance is not stable enough. In the paper, the parts of the peripheral closed loop servo are conformed in an FPGA slug. This module can realize the closed loop control functions which are necessary for the frequency stabilization. So, the whole system is not only integrated and minityped, but also can be intelligent controlled; the stabilization is greatly increased, and it enables the accuracy to reach 10-8rad.
The microstrip patch antenna is a low-profile low cost robust planar structure. A wide practical range of can be obtain with this type of antenna and, due to the ease of manufacture, is inexpensive compared with other types of operation, low gain, and a potential decrease in radiation efficiency due do surface-wave losses. In this paper, a new type of high directivity PBG patch antenna is proposed. It has been demonstrated that take advantages of both the suppression of surface waves and high directivity.
In this paper, Fiber Bragg Grating external cavity semiconductor laser and Blazed grating external cavity semiconductor laser are analyzed in theory. Some experiments on two types of Blazed Grating external cavity laser (Littrow and Littman set-up) are done, and some conclusions are also obtained. Two set-ups are compared in detail; at last the intending application of the laser is prospected.