Filter Toolbox - AWG Designer

The Filter Toolbox - AWG Designer gives you easy access to years of expertise & insights into AWG design, layout & simulation. The toolbox plugs into IPKISS and enables you to:

  • easy share & quickly converge on your design in days instead of weeks.
  • deliver DRC-clean devices, ready for tape-out,  that can be deployed into libraries for circuit simulation & layout
Filter toolbox inside the IPKISS flow
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Key features

Control high-level specs of AWGs
  • Number of output channels
  • Output channel wavelengths or frequencies, equidistant in frequency or wavelength, or non-equidistant
  • Free spectral range
Simulate
  • Insertion loss
  • Channel accuracy
  • Next channel cross-talk
  • Inter channel cross-talk
  • Noise floor
  • Isolation
  • Insertion loss uniformity
  • Channel bandwidth
  • Channel edge roll-off
  • Intra-band ripple
  • Process variations
Customize
  • Number of grating arms
  • Waveguide width
  • Bend radius
  • Aperture type
  • Output aperture spacing
  • Star coupler grating period
  • Number of dummy apertures
  • AWG form-factor
Manufacture
  • Ready DRC clean GDSII Layout
  • On Silicon On Insulator or Silicon Nitride
  • Indium Phosphide and other material systems on demand
Deploy
  • In a hierarchic layout
  • In a hierarchic circuit simulation
  • In L-Edit from Mentor, A Siemens Business using IPKISS.eda
Support & Services
  • Expert design support
  • Customization services available

Stories 

Master the key design parameters

AWG system The AWG resembles a lens-based imaging system: the field profile of the input aperture is projected by a 'lens' (the apertures and the waveguides) onto the output aperture. The waveguides act as a prism that is inserted between the lenses. It is not a perfect imaging system, because the waveguide array partitions the field into discrete 'pixels'.

Arrayed Waveguide gratings are most commonly used as wavelength (de)multiplexers: light with many wavelength channels comes in, and the wavelength channels are sepatared into different output waveguides.

 

Design specifications

The important criteria for designing a demultiplexer are:

  • FSR
  • Center Frequency
  • Channel Spacing
  • Number of Channels
  • Apertures
  • Waveguides
  • Free Propagation Region
  • Number of grating arms

Performance metrics

The important metrics in the performance of an AWG demultiplexer are

  • Insertion loss of the channels (i.e. how much light is coupled to the correct output)
  • Crosstalk, which can come from the rolloff of the nearest neighbours or from the sidelobes of other channels
  • Intra-band ripple, or transmission variations within a pass band
  • 3dB bandwidth, which is the width of the passband
  • Uniformity between passbands
  • Channel Registration, or the accuracy with which the passband fits the targeted frequency/wavelength.

 

A design example

A DEMUX with the following high-level specs:

  • C-band (1530 - 1561 nm) AWG
  • Number of channels: 8
  • channel spacing: 200 GHz
  • FSR: 2000 GHz
  • center frequency: 193.4 THz
  • aperture core width: 2.0 um

 

The AWG designer combines physical simulation by CAMFR, the IPKISS modal solver, mathematical formulas and circuit simulation by CAPHE, the IPKISS circuit simulator to calculate parameters such as:

  • number of arms
  • grating circle
  • aperture spacing
  • waveguide lengths

Simulation results show that an improvement of the insertion-loss uniformity and the channel bandwidth are out of spec. Next we show how to improve these using the available tools from the Filter Toolbox:

A possible strategy to improve the insertion-loss uniformity: Increase the FSR

Increasing the FSR from 2000GHz to 3000GHz brings insertion loss difference down from 1.16dB to 0.49dB. The result is that the AWG's

  • number of arms is up from 37 to 56
  • the footprint is up 40% from 160,000 µm2 -> 218,000 µm2

 

To increase the channel bandwidth, explore the type and shape of the apertures

A first strategy is to use an MMI aperture. We have used CAMFR, the IPKISS modal solver, to establish the optimal length of this device and thus an optimal field profile.

This has

  • increased the channel bandwidth
  • increased the insertion loss by 3dB

 

Starting from our extensive validated component library, we can assist you in the creation and validation of new model libraries