BS EN 62496-4-2011 pdf download.Optical circuit boards Part 4 : Interface standards General and guidance.
NOTE It the OCS tail has a mark In the vicinity of Its end, the OCB tail length is the distance between the mark and the end of the OCB body.
3.1.6
OCB port
position on the edge of the OCB body where OCB tails protrude from the OCB body
NOTE Relative positional accuracy between the OCB port and alignment mark or origin point is important for connection with other boards or devices. The OCB port is defined only for the fibre flexible OCB.
3.1.7
position of the OCB port
coordinates at the intersectional point of the central axis of the optical fibre and the edge of the OCB body
NOTE The coordinates of the OCB port consisting of closely arrayed fibres shall be defined by the coordinates of the OCB port closest to the origin point
EXAMPLE In a case where the OCB body of the fibre flexible OCB Is put In the first quadrant and an outline or an angle of the OCB is In contact with the X-axis or the V-axis, as shown in Figure 8.2 of Annex 8. the coordinates of origin are defined as the origin point of the fibre flexible OCB. it is recommended to set one side of the OCB body parallel to the X-axis or the V.axls. In another case where the alignment mark for assembly of optical components on the 0C8 is located near the I/O ports, the centre of the alignment mark Is defined as the origin point of the OCB.
3.1.8
110 port
window in the OCB through which optical energy enters and/or exits
NOTE The I/O port Is located at the end of the OCB tall, at the edge of the OCB body or at the surface of the OCB where the OCB is connected to optical fibre cables andlor optical components.
3.1.9
alignment mark for assembly of OCB
mark on the OCB body, typically a through hole in the OCB body, for assembly of the OCB to another board and/or equipment
NOTE The coordinates of the alignment mark are defined by the coordinates at the centre of the mark. The alignment mark Is used instead of a datum target in Annex A.
3.2 Core shape definitions
There are two types of core shape, square or circular, for waveguide OCBs
EXAMPLE 1 Square shape consists of four corners formed by extrapolating or interpolating an arbitrary shape by four straight lines, as shown in Figure 1
The six structural parameters for the square core shape are shown in Figure 3. Structural parameters for the circle core shape are defined by NFP (near field pattern) observation of a cross section (see IEC 60793.1-45).
3.2.1
core width (top)
upper horizontal component of the core shape
3.2.2
core width (bottom)
lower horizontal component of the core shape
3.2.3
core height
distance between the lower and upper horizontal lines
3.2.4
core centre
intersection point of two diagonal lines of a quadrangle consisting of four midpoints of four lines of the core shape, as illustrated in Figure 3
NOTE This ntersect,on point corresponds to the centre of gravity in a system of material points.
3.2.5
core inner diameter
diameter of an inscribing circle with its centre at the core centre
3.2.6
core outer diameter
twice the distance between the core centre and the farthest corner of the core shape
4 Coordinates of 110 ports of waveguide OCB
4.1 Structural types of waveguide OCB
OCBs are divided into two types defined by the positions and orientations of their optical 110 ports. According to one type, the Input I output port is defined by the exposed cross-section of a wavegulde at an edge of the board (end face I/O type), as illustrated in Figure 4. or at an edge of a hole formed inside the area of the board, as illustrated in Figure 5. According to another type, the input I output port contains an optical path converter such as a mirror to deflect optical signals out of or into the surface of the board (surface I/O type), as illustrated in Figure 6. An optical path converter can also be defined by a waveguide, which is bent towards the surface of the board, such that its cross-section is exposed on the surface of the board and thereby forms a surface I/O port, as illustrated in Figure 7. A board may contain both types of I/O port. The coordinates of an end face I/O port, as illustrated in Figure 4, are defined by the core centre as set out in 3.10.1.4. A surface I/O port is defined by the projection of an optical path converter, such as a mirror, on the surface of the board, as illustrated in Figure 6. The position of the I/O port in the axis orthogonal to the plane of the board is defined at the surface of the board on which the projection appears. The coordinates of the surface I/O port are defined by the centre of the projected area of the optical path converter on the surface or the centre of the core of a bent waveguide exposed on the surface, as set out in 3.10.1.4. Optical I/O ports on both types of OCB can be distributed in 2 dimensions across a plane shared by the I/O port cross-section. as shown in Figure 4 and Figure 6.BS EN 62496-4-2011 pdf download.