Ultra-high-speed photonic-enabled ADC based on multi-phase interferometry
AssigneeTechnion Research & Development Foundation Limited
InventorsMoshe Nazarathy, Igor Zelniker
Life of this patent
Estimating the term…
Abstract
A ultra high speed photonic Analog to Digital Converted (ADC) for sampling and quantizing an electrical voltage signal, internally enabled by photonics uses coherent optical detection architectures for photonic quantization. Coherent light is phase modulated by the test signal. Using an interferometer, or an array of interferometers the phase of modulated light is compared with a reference light. Flash ADC, successive approximation ADC and delta-sigma ADC configurations are presented.
Claims19
An ultra-high-speed optical analog to digital converter comprising:
- an input for receiving electrical input voltage;
- at least one laser source for providing a train of equally spaced coherent light pulses;
- at least one phase modulator for modulating the phase of said light pulses in response to said electrical input voltage to provide phase modulated light pulses;
- an optical front end comprising at least one optical channel, wherein each optical channel comprises an optical coupler for interfering said phase modulated light pulses with a reference light to create a first and a second interference beams, wherein light intensities in said first and second interference beams depend on relative phase of said phase modulated light pulses and said reference light;
- at least one optical receiver comprising:
- a first and a second photodiode for detecting light from said first and a second interference beams to produce a first and a second photocurrents indicative of intensity of said detected light;
- and an electronic comparator for producing a binary signal indicative of a difference in said first and second photocurrents;
- and an electronic encoding logic, for creating a multi-bit result from a plurality of said binary signals.
A method of photonic analog-to-digital conversion, comprising:
- receiving an electrical analog input test signal;
- generating a coherent laser beam;
- phase modulating said coherent laser beam, thus linearly mapping said input signal into optical phase of a phase-modulated signal beam;
- generating at least a first phase-shifted reference beam coherent with said phase-modulated signal beam, and relatively phase shifted with respect to said phase-modulated signal beam by a first phase shift angle;
- interfering at least a portion of said phase-modulated signal beam with said first phase-shifted reference beam to generate a positive and a negative interference beams;
- and detecting said positive and a negative interference beams and generating a first electrical signal having Boolean value indicative of a sign of a phase difference between said phase-modulated signal beam and said first phase-shifted reference beam.
An opto-electronic Successive Approximation Register type analog to digital converter, comprising:
- an input for receiving electrical input voltage;
- a laser source for providing coherent laser beam;
- a beam splitter for splitting said coherent laser beam to a signal beam and reference beam;
- at least a first input phase modulator for modulating a phase of said signal beam in response to said input voltage;
- at least a first feedback phase modulator for modulating a phase of said reference beam in response to a feedback voltage;
- at least one interferometer for interfering said signal beam and said reference beam and generating a positive and a negative interference beams;
- at least one channel for detecting said positive and a negative interference beams and generating an electrical signal having Boolean value indicative of a sign of the corresponding phase difference between said signal beam and said reference beam;
- and Successive Approximation Register logic unit arranged to use said Boolean electrical signal to provide feedback voltage to said first feedback phase modulator, and to obtain a multiple bits digital value indicative of a strength of said analog input voltage.
Dependencies are inferred from the claim text.