Discover On-Board Optical Module LIGHTPASS^®-EOB 100G vol. 3

I-PEX has developed the LIGHTPASS^®-EOB 100G on-board optical module. This article describes the detailed contents of that optical module.
To check out for previous chapter, visit the article of vol.2.

3: High-speed, low-profile electrical connectors

To develop a high-speed and low-profile optical module, we use a CABLINE^® connector.
Features of CABLINE^®-CA/CAF and CABLINE^®-CA is a 0.4 mm pitch connector. Even with a 60-pin connector, the occupied area on the board is only 30.95 mm in width and 5.73 mm in depth, making it an ultra-compact, low-profile connector with a height of 1.0 mm.

Its features include a mechanical lock bar, which prevents incomplete mating or accidental disengagement. CABLINE^®-CA is a connector designed for handling multiple micro-coaxial cables (mainly for transmitting differential signals or control signals). It has multiple ground connections and excellent high-frequency transmission characteristics. Additionally, CABLINE^®-CAF is designed to accommodate FPCs into the plug shell and is compatible with the same CABLINE^®-CA receptacle.
CABLINE^®-CA/CAF Outline

Name	CABLINE^®-CA / CAF
Mating Type	Horizontal mating type
Pitch	0.4 mm
Pin Count	60 pin
Height	Mating condition : 1.00 mm
Depth	Mating condition : CA 5.73 mm : CAF 6.06 mm Receptacle only : 4.15 mm
Width	CA : 30.95 mm CAF : 29.75 mm
Product Standard/TR	CA : PRS-1968/TR-16023 CAF : PRS-2465/TR-18016

4: Ultra-low-profile fiber array

In the development of the LIGHTPASS^®-EOB 100G ultra-thin optical module, it was necessary to adopt diagonally cut fibers instead of fibers bent at 90 degrees, to achieve a low-profile design. Here's an explanation of the purpose behind this decision and the details of the fiber array.

1) Reduced Height through Diagonally Cut Fiber Array

The implementation of a diagonally cut fiber array has enabled a low-profile design, allowing optical modules to be positioned closer to ASIC. This placement has led to a reduction in transmission losses in substrate wiring. Additionally, it allows for a common heat dissipation design with ASICs.

2) Diagonally Cut Fiber Array

Ultra-thin Fiber Array Utilizing Reflection from Fiber End-face Mirrors.
We applied a fiber array where fibers aligned on V-groove glass were diagonally cut to serve as mirrors. This approach effectively reduced the height of the fiber block, achieving a module height of 2.3 mm.