In the era of big data, the demand for data transmission in data centers is increasing, and AOC active optical cables play an important role in data centers as important devices for data transmission. Below, we will introduce the introduction and application of 25G SFP28 AOC active optical cable.

I. Core Features and Advantages

1. Optoelectronic integration design: electrical signals are converted into optical signals in optical modules at both ends, and transmitted through multimode optical fibers (OM3/OM4) to avoid electromagnetic interference (EMI).
Transmission performance: Distance: OM3 supports 70m, OM4 supports 100m (far exceeding the 5m limit of DAC copper).
Rate: 25.78Gbps NRZ encoding, compatible with IEEE 802.3by standard.
Latency: End-to-end ≤0.1μs (close to direct-connect copper).
2. Plug and Play: Driver-free, hot-plug compatible with mainstream switches (such as Cisco Nexus, Arista 7050).
Lightweight wiring: wire diameter ≤3mm (60% thinner than DAC), support high-density cabinet bending (minimum bending radius 15mm).
Power consumption and heat dissipation: single power consumption ≤1W, passive design reduces the cooling burden of the cabinet.

3. Features:

Pluggable SFP28 package type Full-duplex active cable 850nm VCSEL laser and PIN photodetector

Receiver and transmitter built-in CDR circuit

Compliant with SFP28 MSA and IEEE 802.3by 25GBASE-SR Ethernet standard

Maximum speed up to 25.78Gbps

Maximum power consumption per SFP28 module less than 1W

Power supply voltage 3.3V RoHS compliant (lead-free)

Operating temperature 0°C~70°C (commercial grade)

Typical application scenario

Data center server access layer scenario

Requirements: TOR (Top of Rack) switch connection server, distance 10-50m.
Solution configuration: 1 48-port switch + 48 AOC, replacing 96 LC jumpers +48 optical modules, saving 80% wiring space.
Case: Tencent Cloud TB storage nodes adopt 25G AOC, and the failure rate is 40% lower than that of pluggable modules.
2. 5G Fronthaul network

Requirements: ≤ 100m interconnection between AAU (active antenna unit) and DU (distributed unit).
Solution: CPRI/eCPRI protocol support, delay jitter 1ns.
Anti-interference ability: no signal attenuation through 3 meters high altitude cable (copper cable needs additional shielding).
3. Financial high-frequency trading system

Requirements: ultra-low latency interconnection from trading server to core switch.
Optimization scheme: customize 0.5m ultra-short AOC, delay voltage drop to 0.08μs.
Redundancy design: dual AOC link aggregation, switching time 5 ms.

Key considerations for deployment

V. Limitations and coping strategies Distance bottleneck (≤100m) Alternative: >100m scene replaced by 25G LR single-mode module (support 10km).
Non-branching decoupling scheme: 25G DAC (≤5m) or pluggable module + splitter is used when branching is required.
Version compatibility Firmware upgrade: Older switches (such as the HPE 2930F) need to be upgraded to post-2020 firmware support.
Future evolution direction 50G PAM4 upgrade: Existing AOC infrastructure can smoothly transition to 50G SFP56 (NRZ→PAM4).
Liquid cooling compatible design: 20Bar liquid cooling AOC (suitable for submerged data centers) is commercially available.
Intelligent operation and maintenance: integrate EEPROM chip to realize automatic mapping of port-level topology (such as Arista CloudVision).
Selection suggestions: Preferred scenarios: high-density intra-cabinet interconnection (≤100m), EMI-sensitive environment, 5G pre-transmission.
Avoidance scenarios: ultra-long-haul transmission, branching topology, extreme temperature environments (>70°C).

Mainstream manufacturer model reference:

Cisco: SFP-25G-AOC 10M (10m OM4)

Innolight: AOC-S25-30 (30m industrial grade)

H&T: SFP-25G-AOC 1M/AOC 3M/AOC 5M/7M/10M (1M/3M/5M/7M/10M)