Phase masks are surface relief gratings etched in fused silica. In most applications, a phase mask essentially serves as a precision diffraction grating that divides an incident monochromatic beam into two outgoing beams. The incident radiation is usually in the UV range. By generating two outgoing beams, a phase mask creates an interference pattern. This pattern is located in the space where the outgoing beams overlap. Phase masks have a wide variety of applications, but most frequently PMT phase masks (which are themselves gratings) are used to record other gratings, such as planar waveguide gratings in integrated optics devices, and fiber Bragg gratings (FBGs). An FBG is a light frequency filter located in the core of an optical fiber.

 

Phasemask Technology is a world leader in phase mask fabrication. The phase mask manufacturing operation, located in Fremont, CA, involves sophisticated and demanding techniques in microfabrication and holography.

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全光通信的研究还处于起步阶段，许多技术难点需要克服。虽然光纤光栅不能解决全光通信中所有的技术难点，但是对光纤光栅技术和器件的研究可以解决全光通信系统中许多关键技术。因此对光纤光栅的研究可以促进全光通信网的早日实现。

光纤光栅是将来很长一段时间内光纤通信系统中最具实用价值的无源光器件之一，利用它可组成多种新型光电子器件，由于这些器件的优良性能使人们更加充分地利用光纤通信系统的带宽资源。对光纤光栅的研究和开发正逐步深入到光纤通信系统的每一个细节，从波分复用系统的合波/分波、光纤放大器的增益平坦、色散补偿，到全光网络上下路、波长路由、光交换等，光纤光栅的应用将推动高速光通信的发展，将在未来的高速全光通信系统中扮演重要的角色。