The challenges of plastic optical fiber in automobile industry
Cars present a much tougher environment than home electronics. Long time exposure to the dead sun wants fibers able to withstand temperature to 85°C, well above the 65°C standard for indoor consumer electronics. And in cars, things can get a lot hotter. Temparatures in the roof module can easily reach 105°C , which 125°C  is not unusual in the engine compartment. makes using the fiber in the engine compartment impossible.
PMMA POF still have one key limitation: the glass temperature of POF is lower than 100°C.  it can be only be used at temperatures of up to about 85°C . As a result, many car makers are looking for POF that is specified at temperatures of 125°C .
 
The automotive industry is now moving towards an optical fiber with a silica glass core plastic clad (PCS). PCS fiber offers many of the advantages of POF-large core size (0.2mm) and the associated ease of connectorization-but it is also capable of high-performance operation at up to 125°C . The combination of a silica core with a hard polymer cladding offers the best of both worlds: low attenuation and superior fiber strength.


According to Polymicro, the fiber design tested was a 0.02mm synthetic silica core and 0.23 fluoropolymer cladding and a 1.510mm nylon buffer (refer to figure  ). There are obvious environmental conditions to be met, such as:
1.      high temperature (125°C)
2.      Automotive fliud immersion
3.      High tensile force(>60N)
The difference between the POF and PCS are summarized in Table 1.
 
Attenuation(dB/km)
At 650nm
Max temp.
NA
Min. Bend Radius
Ease of Termination
Strength
Chem Durab.
Cost
POF
<200
90°C
0.5
~25mm
Easy
Low
Low
Low
PCS
10
125°C
0.37
~9mm
Moderate
High
High
Moderate
However, the large scale use of PCS in the car stills meet a very higher cost problem compared with PMMA POF. Without enough customer base, the cost of PCS cannot be easily cutted.
BMW supports the activities to bring PCS into cars. However, to date, none of BMW’s cars are equipped with PCS.
 
For more information see:
http://www.polymicro.com