1.25G SFP DWDM Optical Transceiver Module
Product Overview
The Apex 1.25G SFP DWDM module carries Gigabit services on the dense 100GHz C-band grid, where channel spacing is 0.8nm instead of the 20nm used by CWDM. That spacing allows 40 channels and more on one fiber pair, so a saturated cable can be reused many times over instead of being replaced.
DWDM optics are temperature controlled and wavelength stable, which is what makes them compatible with erbium doped fiber amplifiers on longer spans. 1.25G DWDM is used on spans up to 80km and 120km with amplification, and it is the standard answer when a metro or long haul route between two sites is full but the traffic has to grow.
We supply the channel you name, together with DWDM mux/demux modules and amplifiers, and test each module for center wavelength and optical power before it ships. Channel plans, channel numbering and connector types are confirmed on both ends of the link so field splicing and patching do not create surprises.
Key Features
- 1.25Gbps line rate for Gigabit Ethernet and SDH STM-1 / OC-3
- 100GHz (0.8nm) DWDM spacing on the ITU C-band grid
- Reach up to 80km and 120km over single mode fiber with amplification
- Temperature controlled DFB transmitter for wavelength stability
- Duplex LC interface, fixed channel per module
- Digital Diagnostic Monitoring (DDM/DOM) for live optical readings
- Designed for amplified DWDM links and passive mux/demux modules
- SFP MSA and RoHS compliant, coded for your platform
Technical Specifications
| Specification | Detail |
|---|
| Part Number | APX-SFP-1.25G-xxKM-DWDM-yy (yy = channel) |
| Manufacturer | Apex |
| Data Rate | 1.25Gbps |
| Form Factor | SFP, hot pluggable |
| Optical Technology | DWDM, 100GHz spacing, C-band |
| Channel Spacing | 0.8nm (100GHz), ITU grid |
| Reach | 80km and 120km over SMF with amplification |
| Fiber Type | Single Mode Fiber (SMF) |
| Connector Type | LC duplex |
| DDM / DOM | Supported |
| Transmitter | Temperature controlled DFB |
| Compliance | SFP MSA, ITU DWDM grid, RoHS |
| Temperature | 0 to 70C commercial, -40 to 85C industrial on request |
Ordering Options
Family options are listed below as plain text so they can be copied into an RFQ or a spreadsheet.
| Channel | Frequency | Center wavelength | Typical span |
|---|
| C21 | 1560.61GHz | 1560.61nm | 80km / 120km amplified |
| C27 | 1554.94GHz | 1554.94nm | 80km / 120km amplified |
| C34 | 1547.72GHz | 1547.72nm | 80km / 120km amplified |
| C40 | 1543.73GHz | 1543.73nm | 80km / 120km amplified |
| C45 | 1539.77GHz | 1539.77nm | 80km / 120km amplified |
| C52 | 1536.61GHz | 1536.61nm | 80km / 120km amplified |
| C59 | 1531.12GHz | 1531.12nm | 80km / 120km amplified |
Applications
Metro and Long Haul Transport
Grows capacity on existing routes by putting each Gigabit service on its own dense channel instead of adding fiber or new cable.
Amplified Multi Service Links
Works with erbium doped fiber amplifiers on spans that reach 80km to 120km between regeneration points.
Carrier, Utility and Rail Networks
Provides dedicated channels for SCADA, telemetry and voice circuits that have to stay isolated from other traffic on the same cable.
Compatibility
DWDM modules are coded for the host platform you name and are tested on live ports before shipment. Because DWDM links are wavelength specific, we confirm the channel plan, the mux/demux positions and the amplifier gain budget with you before quoting, and we can supply the passive parts and amplifiers on the same order.
Related Products
Frequently Asked Questions
When should I use DWDM instead of CWDM?
Use DWDM when fiber is very limited, when you need more than 18 channels, or when the span is long enough to need amplification. CWDM stays the cheaper choice for shorter spans and fewer channels.
Which DWDM channels are available?
Channels across the C-band 100GHz grid are available, in the common C21 to C59 numbering. Give us the channel plan and we will confirm availability, wavelength and lead time.
How far does 1.25G DWDM reach?
80km and 120km over single mode fiber with amplification, which is typical for metro and long haul Gigabit transport. Unamplified 1.25G DWDM is generally limited to around 40km to 80km.
Can DWDM modules work on an unamplified link?
Yes, but the span has to be short enough for the optical budget and the mux/demux loss. Tell us the fiber route length and we will check the budget before shipping.
Why Choose Apex
- Optical engineering support and supply from 1.25G to 800G, including CWDM and DWDM lines.
- Channel plans, passive modules and amplifiers quoted together so the link budget closes.
- Every module is tested for center wavelength, optical power and error rate before shipment.
- Backed by a 3 year warranty and technical support before and after the sale.
