I am currently working on developing 100Gbps coherent technology for Oclaro. I am currently working on putting together the setup to handle the increase in bandwidth needed to properly test new components for development of our product. This is very much a continuation of the 40Gbps coherent technology but more problems arise as we increase the data rate.
I have worked on developing 40Gbps coherent detection technology for Oclaro. This is used for ultra long haul transmission. This has involved developing the proper control loops for use in the field as well as choosing the right components to optimize performance. In choosing the best components, I am also required to work with our vendors to help them optimize their parts for our purposes. I also run simulations to see how well our technology will perform in the field, and I run tests with our actual equipment to test the performance of our technology.
Before Mintera had merged with Oclaro, I built a 40 Gbps DQPSK transponder prototype in 2008. Similar to my current project, I had to develop the necessary control loops to properly run this device as well as choose the best components to use. To build this prototype, I upgraded an existing DPSK transponder. This involved adding a second board to the device, developing the schematics for the second board, changing the necessary major components on the DPSK card, and rewiring the old card to be compatible for DQPSK technology. Also, a new user interface was needed to control the device so I helped design the new interface (based off the previous work with DPSK) to run the board. I then helped demonstrate our technology to customers and taught them how to use our prototype. I was also required to test the prototype’s performance under different operating conditions. It is still considered to be one of the top performing DQPSK transponders in the world. (This project was never made into a product.)
When I started working for Mintera in 2006, I started building prototypes for our 40Gbps technology. This involved upgrading older devices. As the technology for components expanded for 40Gbps DPSK, I was required to change the parts in our prototypes to test their performance. I also helped develop control algorithms for these components and work very closely with our vendors to help optimize their parts as well as fix problems with their devices. Most of my time spent helping other companies was with the development of 40Gbps limiting amplifiers, or Lithium Niobate drivers. I had even traveled to some of our vendors’ headquarters to help their development teams improve their design to meet our performance standards.
This was my master’s of engineering thesis. I helped develop a technology that allows the compensation of self-phase modulation in chirped pulse amplification. We apply a negative nonlinear phase shift to a pulsed laser source that counteracts the effects of self phase modulation. For this paper, rather than sample the optical signal after we add dispersion, we synthesize a similar signal by combining two sine waves. The two sine waves are much easier to amplify more due to the decrease in bandwidth so we are able to compensate more self phase modulation using this method than with sampling the optical signal.
Femtosecond Pulsed Fiber Laser
To provide a laser source for my master’s thesis, I build a femtosecond pulsed fiber laser. This involved creating a loop of erbium doped fiber and single mode fiber, with lengths chosen to determine the pulse lengths. Free space optics were then used to filter out one polarization of the light and adjust the polarization to allow enough light for lasing and to allow the pulse formation. This is based off of previous work that can be seen here (figure 2).
Self Phase Modulation Effects Pedal
For my senior project, I looked into applying knowledge of optical transmission properties in audio signal processing. Similar to the effect studied in my master’s thesis, I looked at the effect of applying a volume-based phase shift to an audio signal. This involved simulating that effect with different synthesized tones in MATLAB with varying volumes, as well as finding a good sounding volume to phase change ratio. I then recorded a guitar and applied the same post-processing in MATLAB to be able to hear the effect.