1.25G SFP CWDM Optical Transceiver Module
Product Overview
The Apex 1.25G SFP CWDM module puts 1.25G traffic on a single CWDM channel so many Gigabit services can share one pair of fibers through passive multiplexers. It covers the 18 channel ITU grid from 1271nm to 1611nm at 20nm spacing, and each module is ordered in one fixed channel.
CWDM is the cheaper way to add capacity to a fiber that is already full. The optics use uncooled lasers and do not need the temperature control, amplifiers or channel spacing that DWDM demands, so both modules and passive mux/demux parts cost less, and 1.25G CWDM reaches 40km to 80km on standard single mode fiber.
Typical use is metro and access transport, cable and utility networks, and utility or carrier links between two sites where several Gigabit services have to ride the same cable. We supply the transceivers, the CWDM mux/demux modules and the patch cords together so channels and connectors match on both ends.
Key Features
- 1.25Gbps line rate for Gigabit Ethernet and SDH STM-1 / OC-3
- 18 CWDM channels, 1271nm to 1611nm on the ITU 20nm grid
- Reach up to 40km and 80km over single mode fiber
- Uncooled DFB transmitter, low power consumption
- Duplex LC interface, fixed channel per module
- Digital Diagnostic Monitoring (DDM/DOM) for live optical readings
- Works with passive CWDM mux/demux and OADM modules
- Compliance with SFP MSA, RoHS, coded for your platform
Technical Specifications
| Specification | Detail |
|---|
| Part Number | APX-SFP-1.25G-xxKM-CWDM-yy (yy = channel) |
| Manufacturer | Apex |
| Data Rate | 1.25Gbps |
| Form Factor | SFP, hot pluggable |
| Optical Technology | CWDM, single channel per module |
| Channel Plan | 18 channels, 1271nm to 1611nm, 20nm spacing |
| Reach | 40km and 80km over SMF |
| Fiber Type | Single Mode Fiber (SMF) |
| Connector Type | LC duplex |
| DDM / DOM | Supported |
| Power Supply | 3.3V, uncooled laser |
| Compliance | SFP MSA, ITU CWDM 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 | Center wavelength | Channel | Center wavelength |
|---|
| 1271 | 1271nm | 1471 | 1471nm |
| 1291 | 1291nm | 1491 | 1491nm |
| 1311 | 1311nm | 1511 | 1511nm |
| 1331 | 1331nm | 1531 | 1531nm |
| 1351 | 1351nm | 1551 | 1551nm |
| 1371 | 1371nm | 1571 | 1571nm |
| 1391 | 1391nm | 1591 | 1591nm |
| 1411 | 1411nm | 1611 | 1611nm |
| 1431 | 1431nm | 1451 | 1451nm |
Applications
Metro and Access Capacity Growth
Adds Gigabit services to a cable that is already in use by putting each service on its own CWDM channel instead of pulling more fiber.
Cable, Utility and Carrier Links
Carries voice, data and telemetry channels between two sites over one fiber pair with passive multiplexing at both ends.
Mobile Backhaul and Enterprise Rings
Lights several 1.25G links on a ring or between buildings while keeping spare channels for later services and upgrades.
Compatibility
CWDM modules are coded for the host platform you name and tested before shipment. Because narrowband passive parts are wavelength selective, we normally quote the transceiver pairs together with the matching CWDM mux/demux modules and confirm the channel plan on both ends of the link before shipping.
Related Products
Frequently Asked Questions
What is the difference between CWDM and DWDM?
CWDM uses 20nm channel spacing on 18 channels and needs no cooling or amplification, so it is the lower cost option for shorter spans. DWDM packs channels at 0.8nm and is used where fiber is very limited or spans are long and amplified.
Which channels do you supply?
The full set of 18 CWDM channels from 1271nm to 1611nm is available. In practice most builds use the 1471nm to 1611nm range to keep loss low, so tell us the channel plan and we will quote to it.
How far can 1.25G CWDM reach?
40km and 80km on standard single mode fiber depending on the module grade. Longer spans need amplification, which CWDM does not support, and are usually built on DWDM instead.
Do I need a multiplexer with the module?
Yes for a shared fiber. Each module carries one channel, so a passive CWDM mux/demux is used at each end to combine the channels onto one fiber pair.
Why Choose Apex
- Optical engineering support and supply from 1.25G to 800G, including CWDM and DWDM lines.
- Transceivers, passive mux/demux modules and patch cords quoted together so channels match.
- Every module is tested for optical power, channel accuracy and error rate before shipment.
- Backed by a 3 year warranty and technical support before and after the sale.
