PDK Tech Configuration Schema Reference

This document provides a complete reference for the PDK (Process Design Kit) technical configuration file. It outlines all available properties and their expected formats.

Reusable Definitions

These are common data structures that are used in multiple places throughout the schema.

lppAsStringOrStringTuple

Defines a layer-purpose pair (LPP). This can be specified in one of two ways:

• A single string that refers to a named LPP defined in the top-level lpps section.

• An array containing exactly two strings: [layer_name, purpose_name].

colorAsStringOrIntTriplet

Defines a color. This can be specified in one of two ways:

• A string, which can be an HTML color name (e.g., "blue") or a hex code (e.g., "#FF5733"). Here’s the full list of supported color names.

• An array containing exactly three integers (from 0 to 255) representing an RGB value (e.g., [255, 87, 51]).

Top-Level Configuration

version

The version of the PDK.

Type:

string

Required:

No

type

Type of library, will influence how the technology will be loaded.

Type:

string

Required:

No

Default:

pdk

Allowed Values:

pdk, adk, tdk

layers

The list of all available layers (ProcessLayer in IPKISS) in the PDK.

Type:

Array of Objects

Required:

No

The object properties are:

Property	Type	Required	Description
name	String	Yes	The unique name of the layer. Case matters.
number	Integer	No	The layer number. Will be auto-generated if absent.
doc	String	No	An optional description for the layer.
ipkiss	Object	No	Ipkiss-specific properties. Contains an optional name (String) if the Ipkiss process name is different. - This is meant for resolving bw incompatibilities
properties	Object	No	A freeform key-value map for attaching custom data to the layer.

purposes

A list of purpose definitions for the layers. The DRAWING purpose is implicitly pre-defined.

Type:

Array of Objects

Required:

No

The object properties are:

Property	Type	Required	Description
name	String	Yes	The name of the purpose (e.g., DOC, Cladding).
number	Integer	No	The purpose number. Will be auto-generated if absent.
doc	String	No	An optional description of the purpose.
ipkiss	Object	No	Ipkiss-specific properties, such as a different name or an extension.
properties	Object	No	A freeform key-value map for attaching custom data to the purpose.

lpps

Layer-purpose pair definitions (PPLayers in IPKISS). These are named shorthands that can be used elsewhere in the configuration. For all layers, an LPP of [layer_name, "DRAWING"] is added implicitly.

Type:

Array of Objects

Required:

No

The object properties are:

Property	Type	Required	Description
name	String	Yes	A unique name for the layer-purpose pair.
lpp	Array of 2 Strings	Yes	The layer-purpose pair as [layer_name, purpose_name].
doc	String	No	An optional description of the LPP.
ipkiss	Object	No	Ipkiss-specific properties, like a different name or a tech_path.
properties	Object	No	A freeform key-value map for attaching custom data to the LPP.

gds

Configuration for GDS file export.

Type:

Object

Required:

No

gds.layer_table

An array mapping LPPs to GDS layer and datatype numbers.

Type:

Array of Objects

Required:

No

The object properties are:

Property	Type	Required	Description
lpp	lppAsStringOrStringTuple	Yes	The layer purpose pair to map.
number	Array of 2 Integers	Yes	The GDS number as [layer_number, datatype].

gds.export_options

A key-value map of options for the GDS export process.

Type:

Object

Required:

No

Property	Type	Default	Description
cut_path	Boolean	true	Whether to cut paths.
path_to_boundary	Boolean	true	Whether to convert paths to boundaries.
path_to_boundary_layers	Array of lppAsStringOrStringTuple	[]	LPPs on which to apply the path-to-boundary filter.
path_to_boundary_exclude_layers	Array of lppAsStringOrStringTuple	[]	LPPs that are excluded from the path-to-boundary filter.
cut_boundary	Boolean	true	Whether to cut boundaries.
write_empty	Boolean	true	Whether to write empty cells.
name_error_filter	Boolean	false	Whether to filter name errors.
max_name_length	Integer	255	Maximum length of GDSII stream names.
max_coordinates	Integer	200	Maximum number of coordinates in GDSII paths.
max_path_length	Integer	100	Maximum length of GDSII paths.
max_vertex_count	Integer	4000	Maximum number of vertices in GDSII boundaries.

display

Display style configuration for visualization tools.

Type:

Object

Required:

No

display.lpps

An array defining display styles for individual LPPs.

Type:

Object

Required:

No

Property	Type	Required	Description
lpp	lppAsStringOrStringTuple	Yes	The LPP for which the display style is defined.
color	colorAsStringOrIntTriplet	Yes	The fill color.
alpha	Number (0-1)	No	The opacity.
pattern	String	No	The fill pattern name.
edge_width	Number	No	The width of the layer’s edge.
edge_color	colorAsStringOrIntTriplet	No	The edge color.

Predefined Fill Patterns**

The pattern property accepts a string that corresponds to one of the predefined fill patterns. These patterns are used to control the visual appearance of layers in layout visualizations. Below is a list of the available pattern names:

• 220-5-cross-hatched

• 220-5-degree-down

• 220-5-degree-up

• 670-5-degree-down

• 670-5-degree-up

• checkerboard-2px

• coarsly-dotted

• cross-hatched

• dots-sparse

• dots

• dotted

• filled

• grid-dense

• grid-sparse-thick

• grid-sparse

• grid-thick

• grid

• heavy-checkerboard

• hollow-bubbles

• hollow

• horizontal-dense

• horizontal-sparse-thick

• horizontal-sparse

• horizontal-thick

• horizontal

• left-hatched

• lightly-cross-hatched

• lightly-left-hatched

• lightly-right-hatched

• lines-diagonal-left

• lines-diagonal-right

• lines-horizontal-bold

• lines-horizontal-dense

• lines-horizontal

• lines-vertical-bold

• lines-vertical-dense

• lines-vertical

• minus

• no-stipple

• plus

• pyramids

• right-hatched

• sine

• solid-bubbles

• solid

• special-pattern-for-light-frame-dithering

• special-pattern-for-light-heavy-dithering

• strongly-cross-hatched-sparse

• strongly-left-hatched-dense

• strongly-left-hatched-sparse

• strongly-right-hatched-dense

• strongly-right-hatched-sparse

• triangle

• turned-pyramids

• vertical-dense

• vertical-sparse-thick

• vertical-sparse

• vertical-thick

• vertical

• zig-zag

display.custom_colors

A key-value map for defining custom named colors. The key is the color name and the value is a color definition colorAsStringOrIntTriplet.

Type:

Object

Required:

No

display.custom_patterns

An array of objects defining custom fill patterns, each with a name (String) and lines (Array of strings like ".*").

Type:

Array of Objects

Required:

No

settings

General PDK settings.

Type:

Object

Required:

No

settings.metrics

Type:

Object

Required:

No

Property	Type	Default	Description
unit	Number	1e-6	Unit of the GDSII file (e.g., 1e-6 for microns).
grid	Number	1e-9	Discretization grid of the GDSII file.
angle_step	Number	1.0	Angle step used for discretization of bends (in degrees).

settings.open_access

Type:

Object

Required:

No

Property	Type	Default	Description
base_counter	Number	1000	Base counter for open access layers

waveguides

Default settings and parameters for waveguides and traces.

Type:

Object

Required:

No

Property	Type	Default	Description
default_wavelength	Number	N/A	Default wavelength used for waveguide models.
wg_bend_radius	Number	N/A	Default bend radius for waveguides.
wg_wire_width	Number	N/A	Default width of the core of a wire waveguide.
wg_trench_width	Number	N/A	Default width of the trench of a waveguide (from the side of the core to the end of the cladding).
wg_cladding_width	Number	N/A	Total width of the waveguide with cladding. Computed value: wg_wire_width + 2 * wg_trench_width
wg_spacing	Number	N/A	Default spacing between waveguides used in adapters.
wg_dc_spacing	Number	N/A	Default spacing for directional couplers. Computed value: wg_wire_width + 0.18
wg_short_straight	Number	N/A	Default minimum length for any straight sections in a route.
wg_short_transition_length	Number	N/A	Default length of a taper.
wg_short_taper_length	Number	N/A	Default length of a taper. Computed value: short_transition_length
wg_overlap_extension	Number	N/A	Default extension of the overlap for trench waveguides.
wg_overlap_trench	Number	N/A	Default trench of the overlap for trench waveguides.
wg_expanded_width	Number	N/A	Default width of expanded waveguides.
wg_expanded_taper_length	Number	N/A	Default length of an extended taper for extended waveguides.
wg_expanded_straight	Number	N/A	Default length of an expanded straight waveguide.
wg_angle_step	Number	N/A	Angle step for bends.
wg_slot_width	Number	N/A	Default width of the slot for slotted waveguides.
wg_slotted_wire_width	Number	N/A	Default width of the wire for slotted waveguides.
wg_defaults_n_eff	Number	N/A	Default n_eff for waveguide models.
wg_defaults_n_group	Number	N/A	Default group index used for waveguide models.
wg_defaults_loss_db_perm	Number	N/A	Default loss per m in db used for waveguide models.
wg_defaults_core_layer	String / Null	N/A	Default core layer used in waveguides. Reference to a layer name
trace_bend_radius	Number	N/A	Default bend radius for traces, used for auto-generated bends during routing.
trace_control_shape_layer	lppAsStringOrStringTuple	N/A	Reference to a layer name. This layer is used for drawing the control shape.
trace_default_layer	lppAsStringOrStringTuple	N/A	Reference to a layer name. This layer is used as default for drawing trace shapes.
trace_draw_control_shape	Boolean	false	If set to true, a control shape is drawn on top of the waveguide. This can be useful for debugging.

picazzo

Settings specific to the Picazzo library for component generation.

Type:

Object

Required:

No

Property	Type	Description
metal1_layer	lppAsStringOrStringTuple	Default layer for M1 guides.
metal2_layer	lppAsStringOrStringTuple	Default layer for M2 guides.
via12_layer	lppAsStringOrStringTuple	Default layer for M12 vias.
wg_text	lppAsStringOrStringTuple	Default layer for text on a design.
wg_process	String	Default process for waveguides (e.g., "WG").
rwg_process	String	Default process for rib waveguides.
fc_process	String	Default process for fiber couplers.
sil_process	String	Default process for modulators.

picazzo.io_adapter

Settings for I/O fiber couplers adapters.

Type:

Object

Required:

No

Property	Type	Default	Description
iofibcoup_connect_transition_length	Number / Null	null	Connection transition length for I/O fiber couplers.
iofibcoup_fanout_length	Number	N/A	Fanout length for I/O fiber couplers.
iofibcoup_fiber_coupler_transition_length	Number / Null	null	Fiber coupler transition length for I/O fiber couplers.
iofibcoup_s_bend_angle	Number	N/A	S-bend angle for I/O fiber couplers.

picazzo.io_fibcoup

Settings for fiber couplers (curved and straight gratings).

Type:

Object

Required:

No

Property	Type	Description
curved_socket_margin_from_grating	Number	Margin from grating for curved fiber coupler sockets.
curved_grating_angle_span	Number	Angle span for curved fiber coupler gratings.
curved_grating_box_width	Number	Box width for curved fiber coupler gratings.
curved_grating_focal_distance	Number	Focal distance for curved fiber coupler gratings.
curved_grating_n_o_lines	Integer	Number of lines for curved fiber coupler gratings.
curved_grating_period	Number	Period for curved fiber coupler gratings.
curved_grating_start_radius	Number	Start radius for curved fiber coupler gratings.
curved_socket_length	Number	Socket length for curved fiber couplers.
curved_socket_straight_extension	Array of Number	Straight extension for curved fiber coupler sockets.
default_socket_length	Number	Socket length for default fiber couplers.
straight_grating_box_width	Number	Box width for straight fiber coupler gratings.
straight_grating_line_width	Number	Line width for straight fiber coupler gratings.
straight_grating_n_o_lines	Integer	Number of lines for straight fiber coupler gratings.
straight_grating_period	Number	Period for straight fiber coupler gratings.
straight_socket_length	Number	Socket length for straight fiber couplers.

picazzo.modulators

Detailed parameters for phase shifters and modulators.

Type:

Object

Required:

No

Property	Type	Description
phaseshifter_latpn_bridge_pitch	Number	Bridge pitch for lateral PN phase shifters.
phaseshifter_latpn_bridge_width	Number	Bridge width for lateral PN phase shifters.
phaseshifter_latpn_junction_offset	Number	Junction offset for lateral PN phase shifters.
phaseshifter_longpn_n_length	Number	N-region length for longitudinal PN phase shifters.
phaseshifter_longpn_n_width	Number	N-region width for longitudinal PN phase shifters.
phaseshifter_longpn_p_length	Number	P-region length for longitudinal PN phase shifters.
phaseshifter_longpn_p_width	Number	P-region width for longitudinal PN phase shifters.
phaseshifter_pn_junction_overlap	Number	Junction overlap for PN phase shifters.
phaseshifter_pn_nplus_extension	Number	N+ extension for PN phase shifters.
phaseshifter_pn_nplus_offset	Number	N+ offset for PN phase shifters.
phaseshifter_pn_nplus_width	Number	N+ width for PN phase shifters.
phaseshifter_pn_n_cont_offsets	Array of Number	N-contact offsets for PN phase shifters.
phaseshiftern_pn_n_cont_pitch	Number	N-contact pitch for PN phase shifters.
phaseshifter_pn_n_metal1_offset	Number	N-metal1 offset for PN phase shifters.
phaseshifter_pn_n_metal1_width	Number	N-metal1 width for PN phase shifters.
phaseshifter_pn_n_sil_extension	Number	N-silicide extension for PN phase shifters.
phaseshifter_pn_n_sil_offset	Number	N-silicide offset for PN phase shifters.
phaseshifter_pn_n_sil_width	Number	N-silicide width for PN phase shifters.
phaseshifter_pn_n_width	Number	N-width for PN phase shifters.
phaseshifter_pn_pplus_extension	Number	P+ extension for PN phase shifters.
phaseshifter_pn_pplus_offset	Number	P+ offset for PN phase shifters.
phaseshifter_pn_pplus_width	Number	P+ width for PN phase shifters.
phaseshifter_pn_p_cont_offsets	Array of Number	P-contact offsets for PN phase shifters.
phaseshifter_pn_p_cont_pitch	Number	P-contact pitch for PN phase shifters.
phaseshifter_pn_p_metal1_offset	Number	P-metal1 offset for PN phase shifters.
phaseshifter_pn_p_metal1_width	Number	P-metal1 width for PN phase shifters.
phaseshifter_pn_p_sil_extension	Number	P-silicide extension for PN phase shifters.
phaseshifter_pn_p_sil_offset	Number	P-silicide offset for PN phase shifters.
phaseshifter_pn_p_sil_width	Number	P-silicide width for PN phase shifters.
phaseshifter_pn_p_width	Number	P-width for PN phase shifters.

ports

Settings related to component ports.

Type:

Object

Required:

No

Property	Type	Description
default_length	Number	Default length used for ports.
default_layer	lppAsStringOrStringTuple	Default LPP used for ports.

blocks

Settings for block components like IOColumn.

Type:

Object

Required:

No

Property	Type	Description
default_yspacing	Number	Default vertical spacing between blocks.
default_width	Number	Default width of blocks.