Integrated wavelength locker
AssigneeJuniper Networks, Inc.
InventorsJohn Parker, Jared Bauters, Jonathan Edgar Roth, Erik Norberg, Gregory Alan Fish
Life of this patent
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Abstract
Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.
Claims20
An integrated photonic circuit (PIC) comprising
- a tunable light source;
- and
- a wavelength locker comprising an asymmetric Mach-Zehnder interferometer (AMZI) with an output coupler having a plurality of output ports and, placed at the plurality of output ports, a plurality of respective photodetectors for measuring respective optical interference signals exiting the plurality of output ports when light is coupled from the light source into the AMZI, wherein the output coupler and the plurality of photodetectors are configured as a coherent receiver in which relative phase shifts imparted between two signals being interfered to form the optical interference signals differ between at least two of the output ports by a value that is not a multiple of 180°.
A method of manufacturing an integrated photonic circuit (PIC) comprising a tunable light source and a wavelength locker, the method comprising:
- patterning and etching a top silicon layer of a silicon-on-insulator substrate to form integrated optical structures of an asymmetric Mach-Zehnder interferometer (AMZI) in a first region of the top silicon layer and integrated optical structures of a laser diode coupled to an input port of the AMZI and a plurality of photodiodes coupled to a plurality of respective output ports of an output coupler of the AMZI in a second region of the top silicon layer, dimensions of the output coupler and positions of the input and output ports being configured such that phase shifts imparted between two optical signals originating at the input port and interfering at the output ports differ between at least two of the output ports by a value that is not a multiple of 180°;
- depositing and insulating cladding layer on top of the patterned and etched top silicon layer;
- and
- depositing n-doped and p-doped compound semiconductor material on top of the cladding layer above the second region to form the laser diode and plurality of photodiodes.
A method of calibrating an integrated wavelength locker comprising an asymmetric Mach-Zehnder interferometer (AMZI), the method comprising:
- providing a reference signal having a calibration wavelength to an input of the AMZI,
- measuring, at an output of the AMZI, a plurality of optical interference signals each resulting from interference of two signals, wherein a relative phase shift imparted between the two interfering signals differs between at least two of the optical interference signals by a value that is not a multiple of 180°;
- computationally converting the measured optical interference signals to a filter parameter, and
- storing the filter parameter as a target filter parameter in memory.
Dependencies are inferred from the claim text.