3M Co.-Optical Components Program

The Pulse Compressor from 3M Co. of Austin, Texas, manages the chromatic dispersion that can limit transmission speeds in optical communications systems. Earlier solutions required the use of bulky modules with dispersion-compensating fiber, which has high optical attenuation and increased optical linear effects.
Suitable for metropolitan systems, the device corrects for high amounts of dispersion with low optical insertion loss, requiring fewer optical amplifiers. Sub-sea system designers can use it to match the large residual dispersion accumulated over thousands of kilometers of dispersion-mapped fiber trains.

The company says it developed several process technologies and materials to make the Pulse Compressor, including a fiber Bragg grating fabrication technique and special packaging to ensure stability and long-term reliability. The fiber Bragg grating is several meters long with a pitch accuracy of >4 pm. 3M also developed a diamondlike UV-transparent glass and a process whereby it can be deposited on the fiber. The material protects the fiber during grating inscription while maintaining the tight geometry tolerances the fiber needs for long-length-grating fabrication.

The grating period is linearly chirped to reflect lagging wavelengths before faster wavelengths that must travel farther into the grating before they are reflected. An optical circulator separates the light input from the output.