DWDM Tb Photonics Integrated Circuit for Continuous Readout

Award: DE-SC0019581
Program Manager for Industrial Concepts: Dr. Michelle D. Shinn
Program Manager of Advanced Technology R&D: Dr. Manouchehr Farkhondeh
Principal Investigator: Radu Radulescu, Telluric Labs LLC
Subcontractor: MIT Lincoln Lab
DOE SBIR STTR Exchange Meeting 2022: August 24, 2022

TTDAQ Readout Network Specifications

Radiation-hardened
Triggerless, continuous readout for software-driven detectors
Photonic Integrated Circuit (PIC) modulator interfaced directly to sensor preamplifiers
Terabit bandwidth per fiber with up to 64 DWDM channels (100G ITU grid; limited to 32 by foundry PDK with FSR of 3.2THz)
Analog and digital signal transport
GTS protocol enables non-intrusive, in-band timing synchronization over COTS packet networks without hardware timing distribution
FPGA-based picosecond TDC for both detector signals and network packets at backend electronics
High modulation power efficiency

PIC Design Components:

Prometheus Chiplet: 12 differential channels or 24 single-ended, daisy-chainable for 24/48 channels
Phoenix Chiplet: 16 differential 25GE channels, daisy-chainable for 32 channels
Pebbles Chiplet: For testing individual subsystems

Development: Created in partnership with MIT LL
and manufactured at AIM Photonics

RUN 1

RUN 2

Pebbles Chiplet Basic circuits with new MRR designs

Prometheus Chiplet 12 differential channels on 200G ITU grid, expandable with another
PIC for 24 channels on 100G ITU grid

Advantages of DWDM Tb PIC Benefits:

Reduced installation, commissioning, and maintenance costs for nuclear physics experiments
Parallel experiments with independent filtering/software trigger using COTS FPGA accelerator boards
Cost savings for front-end (FE) and cooling systems, enabling lighter detector structures
Passive Optical Networks (PON) provide scalability and flexibility
Uses microring resonator technology, enabling channel multiplexing with minimal power consumption
DWDM signal transmission over miles without amplification
Double/multiple redundancy for laser or resonator failures
PIC size approximately 4x2mm, integrating well with ASICs on pixel array sensors
30+ Gbaud/s per channel
Radiation tolerant as lasers are external, enhancing stability and control

Modulation Techniques Types:

Amplitude Modulation
Phase Modulation using microring resonators with add-drop topology, RAMZI MRR modulation (~10GHz/V)
Functional parameters: laser wavelength/power, heater control, DC bias, RF signal amplitude

Differential Modulation

Phase modulation with π RAMZI – detailed modulation principle available at:
https://ieeexplore.ieee.org/document/8540485

Measurements and Testing

Bench Measurements:

Run 1: MicroRing optical characteristic, Free Spectral Range (FSR) = 3.2 THz

Eye Diagram Analysis:

Single-ended microring resonator measurement vs. simulation
Differential modulator analysis with interferometer transmission comparison