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Fiber MOPA without stimulated Brillouin scattering; Mobius Photonics, Inc.; U.S. Pat. No. 8,009,705

U.S. Patent No. 8,009,705, issued on August 30, 2011 to Mobius Photonics, Inc. of Santa Clara, CA, discloses a fiber-based master oscillator power amplifier (MOPA) that generates optical pulses using a photonic crystal fiber.

    

According to the ’705 patent, conventional high-power laser sources (e.g., for laser micromachining) utilizing a MOPA system cannot generate the high-power laser pulses with pulse widths longer than about 1.7 nanoseconds.  Among the phenomena that can limit the pulse width is stimulated Brillouin scattering (SBS), in which a significant portion of the amplified light is converted to Brillouin-scattered light having a lower frequency than the incident light.  In the system disclosed by the ’705 patent, seed pulses (e.g., from a distributed-feedback or distributed Bragg-reflector type semiconductor diode laser)  are amplified by a photonic crystal fiber amplifier which generates pulses having a peak power greater than 1 kilowatt, but less than the threshold power needed to induce stimulated Brillouin scattering.  This threshold can be increased by frequency chirping the seed pulses. 

According to its website, Mobius Photonics was founded in 2005 and “develops innovative, fast-pulse (from 100′s of picoseconds to 10′s of nanoseconds), fiber-based laser sources for the scientific and industrial markets.”  According to the USPTO database, the ’705 patent is Mobius’ fourth U.S. patent, and its first in 2011.

During prosecution of the ’705 patent, the USPTO rejected the pending claims, citing various prior art references.  One of these rejections cited an earlier-filed application owned by Mobius (which resulted in U.S. Pat. No. 7,529,281) under 35 U.S.C. § 102(e) of the patent law. 

Section 102(e) states that a claim should be rejected if it is anticipated by a patent granted on an application “by another” filed in the US “before the invention by the applicant.”  Under this provision of the patent laws, an applicant’s own work cannot be used against the applicant.  Another provision of the patent laws (§ 102(b)) does allow a public disclosure of applicant’s own work to be used against the applicant if the disclosure occurred more than one year before the priority date, but this condition did not arise in this case.

Under current US law, the applicant is the group of named inventors, not the owner of the application.  For example, although Mobius owns both applications, the applicant for the ’705 patent (i.e., the two inventors) is different from the applicant for the ’281 patent (the same two inventors, plus two other inventors).  On its face, since the inventorship is not identical, the ’281 patent satisfies the “by another” requirement of § 102(e).

However, Mobius was successful in proving to the USPTO’s satisfaction that the ’281 patent did not actually satisfy this requirement of § 102(e).   Mobius filed a declaration in which the two inventors common to both the ’281 patent and the ’705 patent asserted that the two of them, and not the other two listed inventors, were the true source of the relied-upon subject matter of the ’281 patent.  Thus, this material and the claims of the ’705 patent came from the identical group of individuals, so it is not “by another” and it cannot be used to reject the claims of the ’705 patent.  Once Mobius attended to the other rejections, using arguments and claim amendments, the USPTO fould the ’705 patent allowable.

Earlier this year, the “America Invents Act” was signed into law, which includes numerous changes to US patent law, most notably a change from a “first to invent” priority system to a “first inventor to file” priority system (effective for applications filed on or after March 16, 2013).  The act also includes a complete re-writing of § 102 (also effective on March 16, 2013), but which appears to preserve the concept of a disclosure of an inventor’s own work not being usable against him/her, as long as the disclosure occurred within one year of the priority date. 

 
 

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