Optical Communication for Photonic Quantum Computing: Interconnect Bandwidth

Overview of Technical Issues:

The optical interconnect channels insufficiently transmit quantum information between photonic quantum processing units—the bandwidth cannot match the parallel data generation rate of quantum processors, creating a communication bottleneck that limits computational throughput and prevents the system from scaling to higher qubit counts and processing speeds needed for practical quantum computing applications.

Solution directions generated for this problem

Problem Direction 1 :

ImproveOptical channel data transmission rate
VS
ConstraintOptical power dissipation and thermal load

Inspiration 1 : Cross-domain reference

Application Principle: #19 Periodic action
Cross-domain applicability Assess applicability
Methods and apparatuses for charging of electric vehicles
Innovative Solution Refine solution

Burst-mode synchronized optical transmission for quantum interconnects

Synchronize photon transmission with quantum processor computation cycles using burst mode
How to solve :
  • Replace continuous-wave transmission with burst-mode pulsed operation synchronized to quantum processor clock cycles (10–100 ns active bursts, 90–900 ns idle intervals, 10% duty cycle)
  • Implement optical gate switching using electro-optic modulators (LiNbO₃, switching time <5 ns, extinction ratio ≥30 dB) to activate transmission only during processor data-ready windows
  • Deploy thermal buffer periods between bursts for passive heat dissipation through silicon photonic waveguides (thermal conductivity ≥130 W/(m·K)), maintaining junction temperature <4 K for quantum coherence
Expected Effect : Average power reduced 60–80%, peak rate maintained at 100 Gbps, thermal load <50 mW per channel
Risk Control :
  • burst synchronization timing jitter exceeding ±2 ns
  • modulator insertion loss degrading signal-to-noise ratio
  • thermal transient effects during burst transitions

Problem Direction 2 :

ImproveOptical channel data transmission rate
VS
ConstraintInter-channel signal crosstalk

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Power over data line (PoDL) board design method to improve data channel performance
Innovative Solution Refine solution

Time-domain segmented burst transmission with synchronized quantum processor cycles

Replace continuous transmission with synchronized burst mode to isolate channels temporally
How to solve :
  • Partition transmission timeline into non-overlapping time slots (50–100 ns per slot) assigned exclusively to each quantum processor unit, eliminating simultaneous channel activity that causes crosstalk
  • Synchronize burst timing with quantum gate operation cycles using phase-locked loop circuits (jitter <10 ps) to align data output windows with processor computation phases, maximizing throughput during active periods
  • Implement optical time-division multiplexing switches (switching time <5 ns, extinction ratio >30 dB) at interconnect nodes to enforce temporal isolation, blocking crosstalk propagation between slots
Expected Effect : Transmission rate +40%, crosstalk reduced by 25 dB, channel isolation >99.9%
Risk Control :
  • synchronization jitter accumulation across nodes
  • switch extinction ratio degradation over temperature
  • slot allocation inefficiency under variable processor loads

Problem Direction 3 :

ImproveInformation carrying capacity per optical mode
VS
ConstraintOptical power dissipation and thermal load

Inspiration 1 : Cross-domain reference

Application Principle: #35 Parameter changes
Cross-domain applicability Assess applicability
Device under charge, wireless charging apparatus and control method thereof
Innovative Solution Refine solution

Adaptive Orbital Angular Momentum Encoding with Real-Time Thermal Feedback Control

Encode quantum data using orbital angular momentum modes to multiply information density per photon
How to solve :
  • Implement orbital angular momentum (OAM) multiplexing with spatial light modulators generating helical phase fronts — each photon carries log₂(M) bits where M=8–16 OAM modes, tripling information density without increasing photon count
  • Deploy real-time thermal monitoring using fiber Bragg grating sensors (±0.1°C accuracy) at quantum processor interfaces, feeding temperature data to adaptive control loop with 10 μs response time
  • Dynamically adjust OAM mode order and modulation depth based on thermal state — reduce to M=4 modes when temperature exceeds 4.2K threshold, restore to M=16 when below 4.0K, maintaining quantum coherence while maximizing throughput
  • Use mode-selective photonic lanterns (insertion loss <0.5 dB, crosstalk <-25 dB) to multiplex/demultiplex OAM channels in single-mode fibers, ensuring modal orthogonality and preventing inter-mode power leakage
Expected Effect : Information density +200–300%, power dissipation unchanged, thermal load ±5% variation
Risk Control :
  • OAM mode purity degradation during propagation
  • thermal sensor calibration drift in cryogenic environment
  • adaptive control loop latency causing transient overheating

Problem Direction 4 :

ImproveSystem scalability to higher qubit counts
VS
ConstraintInter-channel signal crosstalk

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Multi-user search system with methodology for personal searching
Innovative Solution Refine solution

Hierarchical Optical Interconnect Architecture with Isolated Quantum Processor Clusters

Partition quantum processors into isolated clusters with dedicated optical links
How to solve :
  • Divide the quantum processor array into independent clusters (8-16 qubits per cluster) with dedicated intra-cluster optical interconnects using single-mode waveguides (core diameter 8-10 μm, spacing ≥50 μm) to prevent electromagnetic coupling between clusters
  • implement hierarchical routing where inter-cluster communication uses spatially separated fiber bundles with physical isolation barriers (≥2 mm separation, metal-coated trenches) to block crosstalk propagation while intra-cluster links operate at high density
  • deploy optical isolation amplifiers at cluster boundaries with crosstalk suppression ≥40 dB, regenerating signals to strip accumulated noise before forwarding to adjacent clusters
Expected Effect : Scalability to 1000+ qubits with crosstalk <-35 dB; throughput 100 Gbps per cluster
Risk Control :
  • cluster size optimization trade-off
  • isolation barrier fabrication precision
  • amplifier noise accumulation

Problem Direction 5 :

ImproveInformation carrying capacity per optical mode
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
PPDU transmission method and related apparatus
Innovative Solution Refine solution

Multi-core fiber bundle architecture with wavelength-isolated channel clusters

Partition channels into isolated spatial domains to achieve density and separation simultaneously
How to solve :
  • Deploy multi-core fiber bundles where each core carries 8–12 densely-packed wavelength channels (0.4nm spacing, C-band 1530–1565nm) — tight spectral packing maximizes information density within each isolated core
  • Maintain ≥50μm inter-core pitch with trench-assisted refractive index profiles (Δn≥0.02) to suppress core-to-core crosstalk below −40dB, ensuring spatial isolation between channel clusters
  • Implement fan-in/fan-out photonic integrated circuits using silicon nitride waveguides (loss <0.5dB/cm) to interface each fiber core with dedicated quantum processor units — preserves isolation while enabling scalable connectivity
Expected Effect : Channel density +600%, crosstalk <−40dB, scalable to 1000+ qubits
Risk Control :
  • fiber core alignment tolerance ±1μm
  • fan-in/fan-out insertion loss variation
  • thermal expansion mismatch between fiber and PIC
Patsnap Eureka Solution