[转帖]An 8-skip-0 WDM filter
An 8-skip-0 WDM filter is capable of adding or dropping 8 channels of a 100-GHz spacing fiberoptic telecommunication system. The design we present has the following specifications:<UL>
<LI>centered at 1550 nm,
<LI>passband width of 6.0 nm at the -0.5 dB (about 89%) transmission level,
<LI>bandwidth of 6.8 nm at the -25 dB (about 0.3%) transmission level,
<LI>0.1% ripple in the passband
<LI>materials H (index 2.065) and L (index 1.47) </LI></UL>
<P>TFCalc 3.5 has the capability of designing narrow bandpass (NPB) filters using the prototype method. To obtain the steep edges required in this design, we used 13 cavities. After a few minutes, TFCalc produced a design whose performance is shown below.
<P>
<P align=center><IMG src="http://www.sspectra.com/designs/8-skip-0.gif"> </P>The design's width at the -25 dB level is 6.7 nm, which is better than required. The stack formula for this 303-layer design is <PRE>HLHLHLHL 3H
2L
HLH 3L HLHLHL 3H LHLHLHL 3H LH
2L
HLHLHLH 3L HLH 3L HLHLHLH 3L HL 3H
2L
3H LHLHLH 3L HLH 3L HLHLH 3L HLHL 3H
2L
H 3L HLHLHLH 3L H 3L HLHLHLHLH 3L 3H
2L
3H LH 3L HLHLHLH 3L HLHLH 3L HLHL 3H
2L
3H LHLHLHLHLH 3L HLH 3L HLHL 3H L 3H
2L
3H L 3H LHLH 3L HLH 3L HLHLHLHLHL 3H
2L
3H LHLH 3L HLHLH 3L HLHLHLH 3L HL 3H
2L
3H 3L HLHLHLHLH 3L H 3L HLHLHLH 3L H
2L
3H LHLH 3L HLHLH 3L HLH 3L HLHLHL 3H
2L
3H LH 3L HLHLHLH 3L HLH 3L HLHLHLH
2L
HL 3H LHLHLHL 3H LHLHLH 3L HLH
2L
3H LHLHLHLH
</PRE> 高手，我怎么看不懂，请搞通俗一点吗。 http://www.opto-tech.com/read.php?tid=77 高手，我怎么看不懂，请搞通俗一点吗。 {:12_127:}
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