Optical Frequency Stabilized Phase Locked Loop

Tech ID: 31928 / UC Case 2019-424-0


Conventional optical phase recovery solutions such as digital signal processing (DSP) and optical phase locked loops (OPLL) consume large amounts of power and operate on large-linewidth lasers. These requirements limit data center interconnect (DCI) capacity and require high-bandwidth architectures that further increase power consumption. In addition, conventional DSP carrier phase recovery and GHz-tier conventional OPLLs struggle to support high-frequency fiber links without orders of magnitude higher power. Consequently, phase error is restricted to lower modulation orders and lower spectral efficiency coherent modulations. Establishing high-capacity data center communications is limited by power consumption and low modulation. 


Researchers at the University of California, Santa Barbara have created a device that enables low-power fiber optic coherent communication in DCIs without conventional EPLLs/OPLLs by using an optical-frequency-stabilized phase-locked-loop (OFS-PLL). This new type of frequency-stabilized optical carrier and phase-locking technique operates DSP-free with very low-speed, low-power, and small-footprint electronics. OFS-PLL reduces power consumption via successive laser stabilization stages to reduce total system bandwidth to order of 100s of kHz. Additionally, the phase locked OFS-PLL achieves a homodyne phase error that supports Terabit-per-second fiber links with lower power by orders of magnitude. This technology can be ported to CMOS and integrated photonic packages with coherent Terabit links, minimizing the number of circuits per optical carrier, and removing a key barrier to high-capacity coherent links in the DCI. 


  • Reduces power consumption
  • Reduces bandwidth order
  • Enables high-capacity data-center communication efficiency
  • Readily ports to CMOS/photonic laser systems


  • Optical Fiber
  • Laser Diodes

Patent Status

Patent Pending


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  • Blumenthal, Daniel J.
  • Brodnik, Grant
  • Harrington, Mark

Other Information


optic communication, data center interconnect, DCI, OFS-PLL, optical carrier, phase locking

Categorized As

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