Optical delay management solutions for quantum applications
Precision timing synchronization for quantum networks, cryptosystems, and sensing.
IDIL provides precision optical delay management solutions supporting the development of next-generation quantum technologies —from secure communication netwworks to distributed quantum sensing and advanced cryptographic systems. IDIL solutions:
- Fiber stretcher & Piezo driver
- All-fiber Optical Delay Line (ODL)
- Time delay coil
- Delay line interferometer
- Dynamic delay compensation system
- Variable Optical Attenuator (VOA)
The quantum timing challenge
Quantum technologies rely on the precise manipulation and measurement of quantum states across distributed systems. Whether distributing entangled photons for Quantum Key Distribution (QKD), synchronizing nodes in quantum cryptosystems, or coordinating measurement events in quantum sensing networks, maintaining temporal coherence is critical. Key technical challenges include :
- Path length variations: Fiber networks spanning tens of kilometers introduce timing differences due to unequal optical paths
- Environmental instability: Temperature fluctuations and mechanical vibrations cause temporal drifts in fiber-based systems
- Synchronization precision: Quantum correlations degrade rapidly when detection events are misaligned by even nanoseconds
- Network scalability: Multi-node quantum systems require simultaneous timing alignment across multiple channels
Without precise delay compensation, these factors compromise system performance, increase error rates, and limit the practical deployment of quantum technologies.
Application example: 50km entanglement-based QKD network
Recent European testbeds have demonstrated the feasibility of Quantum Key Distribution networks over metropolitan-scale fiber infrastructures, marking a major step toward real-world quantum communications. These systems use quantum entanglement to exchange cryptographic keys with absolute security.
The challenge: In entanglement-based QKD, photon pairs are distributed from a central source to distant network nodes. Detection events must be precisely synchronized—even when signals travel through fibers of unequal lengths over tens of kilometers—to maintain quantum correlations and sustain key generation rates.
IDIL’s solution: In a 50 km QKD network linking three university campuses, our optical delay interferometer modules integrated fiber stretchers and time delay coils, enabling accurate temporal alignment of photons between nodes. These modules compensated for fiber length differences, stabilized synchronization despite thermal drifts, and ensured compatibility with standard telecom infrastructure.
