0/-1 order phase masks (NFH)

Low-cost production of gratings on planar wafers can be accomplished by use of the Nearfield Holography (NFH) technique, which employs a special type of phase mask. The phase mask is made for easy use in a specially modified mask aligner (commercially available from Süss MicroTec) with a conventional UV source as illumination. This technology has distinct production advantages over grating fabrication by direct holography or direct e-beam technology. In addition of fabrication of gratings on semiconductor DFB lasers, the technique is also advantageous in a number of other fine-pitch applications within the telecommunications and sensor industries.

Sample applications include:

It is imperative that the Phase mask is accurate, uniform and defect-free. Through scientific principles and constants of nature, our fabrication process ensures absolute pitch accuracy.

All our production processes take place in a cleanroom environment, giving you high yield through nearly defect-free Phase masks. Phase masks and the NFH technology are thus suitable for mass production of distributed feedback (DFB) lasers.

Other important features of our line of 0/-1 order Phase masks are:

The 0/-1 order principle is advantageous for fine-pitch applications that require complete elimination of unwanted orders. In this geometry, light incident at the Bragg angle is diffracted partially into the minus first order. Self-interference between the minus first order and the undiffracted zero order creates an interference pattern with a pitch equal to the phase mask pitch. Thus, 0/-1 order phase masks have half the pitch of the equivalent +1/-1 order phase masks. Our innovative production techniques allow us to manufacture 0/-1 order phase masks with periods down to 260 nm.