Main Parameters of Fiber Optic Switches

Fiber optic switches are configured based on fiber type, port count, wavelength range, insertion loss, switching time, and polarization characteristics, with vendor-specific options for speed, FEC, and interface settings.

Key Configuration Parameters

1. Fiber Type and Core Size

• Single-mode fiber (SMF): Core ~8 µm, supports long-distance, high-bandwidth transmission, ideal for precise alignment and low dispersion applications .
• Multimode fiber (MMF): Core 50–100 µm, supports multiple propagation modes, suitable for shorter distances and LED sources, with less critical alignment .
• Some switches support polarization-maintaining fibers or hybrid configurations for specialized applications . 2. Port Configuration
• Switches range from 1x4 to 1x36 ports, with options for dual independent switches in a single rack mount .
• Cisco MDS switches support Fibre Channel speeds from 2 Gbps up to 32 Gbps depending on SFP type, with strict compliance to link negotiation standards .
• Port parameters include admin mode, VSAN assignment, transmit/receive B2B credits, and receive data field size . 3. Wavelength Range
• Standard single-mode switches operate over 1250–1670 nm, with performance measured at 1550 nm under controlled conditions .
• Multimode switches typically operate at shorter wavelengths compatible with LED sources. 4. Switching Performance
• Switching time: Time required to change optical paths, critical for high-speed applications .
• Insertion loss: Attenuation introduced by the switch, typically minimized in MEMS-based switches .
• Polarization-dependent loss (PDL): Variation in loss due to polarization, important for sensitive optical systems .
• Cross-talk: Ratio of desired output power to undesired outputs, affecting signal integrity . 5. Control and Interface Options
• Many switches include USB, Ethernet, or serial interfaces for configuration and monitoring .
• Cisco switches allow FEC (Forward Error Correction) and TTS (Transmitter Training Sequence) configuration to improve link reliability over impaired links .
• Shared resource management (BB credits) is required when taking interfaces in or out of service to avoid traffic disruption . 6. Customization and Environmental Considerations
• Switches can be customized for rack-mounting, dual-switch configurations, or specific fiber types .
• Some industrial or medical applications require radiation-resistant fibers, hybrid cables, or specialized coatings .
• Temperature and polarization stability are critical for maintaining low insertion loss and high channel isolation . 7. Vendor-Specific Notes
• Cisco MDS 9000 Series: Focus on Fibre Channel SANs, configurable speeds, VSANs, and strict link negotiation compliance .
• OZ Optics MEMS switches: Low insertion loss, high channel isolation, millions of switching cycles, USB interface, customizable fiber types .
• LEONI FiberSwitch®: Offers polymer optical fibers, hybrid cables, and a wide wavelength range (200 nm–4 µm) for industrial and medical applications .

Summary

When configuring fiber optic switches, consider fiber type, port count, wavelength range, insertion loss, switching time, polarization effects, and interface options. Vendor-specific features like FEC, VSANs, and MEMS technology can enhance performance and reliability. Proper configuration ensures optimal signal integrity, minimal loss, and compatibility with the intended network or test environment .