WDM Design

• Additional Mat mirror activates attempts to consider some mirror layers consisting of an additional material. It is enabled only if at least one additional material is selected.
• Additional Mat cavity activates attempts to consider some mirror layers consisting of an additional material. It is enabled only if at least one additional material

OptiLayer allows additional design settings:

• Symmetrical mirrors allows restricting Global Integer Search procedure to designs with symmetrical mirrors. This restriction increases the speed of the search procedure noticeably, it can be useful for complicated filters with many cavities (more than 6-8).
• Symmetrical cavities allows restricting Global Integer Search procedure to designs with symmetrical cavities. This restriction increases the speed of the search procedure noticeably, it can be useful for complicated filters with many cavities (more than 6-8).
• With Adjust to Incident, the filter is optimized with respect to the actual refractive index of incident medium. Otherwise it is optimized with respect to the incidence medium refractive index equal to that of the substrate. Practical experience shows that it is usually better to optimize a filter using the second option and then to apply an appropriate AR coating on the top of the filter.
• 3H/3L mirror layers allows using 3H/3L layers for filter mirrors. This may improve optimization capabilities of the search procedure. In many cases it allows to obtain solutions of a better quality.
• Composite cavities allows using filter cavities of a complicated structure. This may also improve the filter optimization.

The first layer of the “V” coating is often of the same material as the last layer of the filter. In this case such layers form a single layer and the resulting number of design layers is increased only by 1.

If Export Filter Target is marked, WDM Filter Design option will also export WDM filter target to the OptiLayer environment.

Export to VPI…  allows you to export WDM filter spectral characteristics to VPIphotonics software. Visit www.vpiphotonics.com for more information on VPIphotonics.

You can specify the Transmission level and Rejection level for setting the transmission and rejection bands of a WDM filter. Both values can be entered in absolute values and in dB. Entry fields for these values are synchronized.

Also it is possible to specify whether it is necessary to use a 50% half-width requirement (half-width at the transmission level of 50%).

For more detail see WDM Filters in Design Collection article.

The corresponding setting can be found at the first page of the WDM dialog:

Synthesis –> WDM Filter

1. A. V. Tikhonravov and M. K. Trubetskov, “Automated Design and Sensitivity Analysis of Wavelengh-Division Multiplexing Filters ,” Appl. Opt. 41, 3176-3182 (2002).
2. A. Tikhonravov, M. K. Trubetskov, and A. V. Voronov, “Automated monitoring of WDM filters,” in Optical Interference Coatings, OSA Technical Digest Series (Optical Society of America, 2001), paper WA3.
3. A. V. Tikhonravov and M. K. Trubetskov, “Automated design of WDM filters,” in Optical Interference Coatings, OSA Technical Digest Series (Optical Society of America, 2001), paper WD3.
4. A. Thelen, A. Tikhonravov, M. Trubetskov, and M. Kokarev, “Phase properties of WDM filters,” in Optical Interference Coatings, OSA Technical Digest Series (Optical Society of America, 2001), paper WD5.

Narrow band pass filter consisting of quarter wave, half-wave and full wave layers.

For more detail see WDM Filters in Design Collection article.