Continuous time (CT) Electro Optic Phase Locked Loops (EOPLLs) can significantly reduce the differential delay required in a Mach-Zehnder Interferometer (MZI) which is used to detect the chirp slope, thereby reducing the MZI area and associated loss. However, CT-EOPLLs produce inter-modulation tone at (fref + fbeat) which creates spurs at offsets of ±(fref + fbeat), ±2(fref + fbeat), ±3( fref + fbeat) from the expected beat tone at the ranging output. In this work, we present a CT-EO-PLL which not only breaks the fundamental trade-off between chirp bandwidth and MZI delay, but also completely eliminates spurs from the PLL and laser output by using IQ single-sideband (SSB) and harmonic reject (HR) mixing. This EO-PLL, integrated in CMOS technology, suppresses the spurs at beat note by > 25dB, enabling us to detect an object at a maximum range of > 3.3m, with a precision of 558µm at 2m distance.

© 2019 The Author(s)

PDF Article


You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access OSA Member Subscription