U.S. Patent No. 7,903,712, issued on March 8, 2011 to NeoPhotonics Corp. of San Jose, CA, discloses a VCSEL structure having a reduced capacitance and improved high-frequency performance.
A vertical cavity surface emitting laser (VCSEL) is a semiconductor laser diode having a stacked quantum well structure between two reflectors that emits laser light perpendicularly to the stack with a resonant wavelength. To allow the resonant wavelength to be tunable, one of the reflectors can be placed on a cantilever arm that is deflected electrostatically to vary the spacing between the reflectors, and hence adjust the resonant wavelength.
According to the ‘712 patent, various properties (e.g., the single mode, surface mode, and compact size) of VCSELs make them desirable for use in fiber optic telecommunication systems. However, parasitic capacitance can degrade the output power of such VCSELs, and existing methods of reducing the capacitance using deep proton implantation to create electrically isolating regions have several drawbacks (e.g., damage that cannot be annealed away, damage to the cantilever, increased processing times). The ‘712 patent discloses an etch process to create voids that physically and electrically isolate the device active area, thereby reducing parasitic capacitance, without proton implantation.
According to its website, NeoPhotonics is “a leading designer and manufacturer of photonic integrated circuit, or PIC, based modules and subsystems for bandwidth-intensive, high-speed communications networks.” The company raised about $83 million through its initial public offering on February 2, 2011 with a starting price of $11.00/share. The share price quickly reached a high of about $21/share, but is currently priced between $8-10/share.
Reviewing the file history of the ‘712 patent, it apparently began as a patent application filed by Bandwidth9, Inc. in September 2004 after the company filed for Chapter 11 bankruptcy protection in August 2004. NeoPhotonics eventually purchased the patent application that resulted in the ‘712 patent from Bandwidth9. However, during the transfer from Bandwidth9 to NeoPhotonics, a reply to a pending USPTO notice was not filed, so the patent application went abandoned. The error was not discovered by NeoPhotonics for about two years, upon which the company filed a petition for revival of the application on the grounds that the delay in replying to the USPTO notice was unintentional.
Such revivals of abandoned patent applications are permissible under U.S. law, as long as that the entire delay in filing the required reply was unintentional. Generally, all that is required is a statement by the applicant that the entire delay was unintentional, but in cases where the USPTO questions whether the entire delay was unintentional, the USPTO can require further detailed information regarding how the delay came to be, as was done for this application. After examining the additional information provided by NeoPhotonics, the USPTO granted the petition for revival.
Partially due to this unintentional delay, the ‘712 patent issued with an additional 1913 days of patent term (the time that the patent may be asserted against accused infringers). The standard term of a U.S. patent is 20 years from the filing date of the patent application, however, in certain circumstances, additional time may be granted, e.g., to make up for delays in the USPTO’s handling of the patent application. As a result, instead of expiring in September 2024, the full patent term of the ‘712 patent will not expire until about December 2029.
According to the USPTO database, NeoPhotonics received three U.S. patents in 2010 and seven in 2009. The ‘712 patent is the first U.S. patent obtained by NeoPhotonics in 2011, with a second one (U.S. Pat. No. 7,905,114 regarding a method of forming optical fiber preforms) having been issued on March 15, 2011.