Appeal No. 2007-0400
Application 10/788,054
applicant can overcome a rejection [for obviousness] by showing insufficient
evidence of prima facie obviousness or by rebutting the prima facie case with
evidence of secondary indicia of nonobviousness.”).
ANALYSIS
The reference discloses a reconfigurable DWDM (Dense Wavelength
Division Multiplexing) optical transmitter that employs “n” active lasers and “k”
spare lasers (col. 5, ll. 46-47) and typically employs two spare lasers
for every eight active lasers (col. 13, ll. 7-8).
Referring to Figure 2, the transmitter employs a common gas cell 208
comprising a gas of a known spectral line frequency and one etalon (also called the
grid generator) 212 to establish a frequency grid for “n” lasers 202 and therefore
“n” channels (col. 7, ll. 15-23). More particularly, the etalon generates a comb of
equally spaced laser wavelengths (col. 5, ll. 50-52; Fig. 4), also referred to as
“successive fringes” (col. 7, ll. 22-23). A reference frequency control loop 228
initializes and tunes each laser to the reference spectral frequency derived from gas
cell 208 (col. 7, ll. 23-25). A grid positioning control loop 226 sequentially tunes
each laser 202 in the bank to a respective “fringe” of the frequencies of grid
generator 212 (col. 7, ll. 20-28). The optical paths of all of the lasers, including the
spare lasers, are always connected to the output of transmitter module 225 (col. 7,
ll. 59-63).
As shown in Figure 1, which depicts only one of the lasers, a “Detector 1”
(314) provides the control input for the reference frequency control loop 228
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Last modified: September 9, 2013