25G SFP28 DWDM Optical Transceiver Module
Product Overview
The Apex 25G SFP28 DWDM module carries a 25 Gigabit service on one dense wavelength division multiplexing channel of the C-band at 100GHz spacing. The narrow grid allows dozens of 25G services on one fiber pair, which is what makes it the right part when a route has more traffic than a coarse plan can hold.
25G DWDM is used on metro and regional routes, dark fiber leases and fronthaul or mid haul runs where many sites have to share one cable. The C-band channels sit inside the gain window of erbium doped fiber amplifiers, so spans can be extended past the module grade with an inline amplifier rather than a regenerator.
Use of the 25G CWDM grid keeps the option open to add more channels later on the same fiber. We confirm the channel plan, the mux/demux hardware and whether amplification is in line before quoting, and supply the passive parts and patch cords with the transceivers so the plan matches at both ends.
Key Features
- 25.78Gbps line rate for 25G Ethernet and CPRI / eCPRI fronthaul
- 100GHz C-band channel spacing, fixed channel per module
- 10km and 40km grades, extendable with an inline amplifier
- APD receiver option for spans with high loss or several mux stages
- Duplex LC interface, cooled EML transmitter
- Digital Diagnostic Monitoring (DDM/DOM) with live optical readings
- Operates with passive DWDM mux/demux, OADM and EDFA modules
- Compliance with SFP28 MSA, ITU 100GHz grid and RoHS
Technical Specifications
| Specification | Detail |
|---|
| Part Number | APX-SFP28-25G-xxKM-DWDM-yy (xx = reach, yy = channel) |
| Manufacturer | Apex |
| Data Rate | 25.78Gbps (also 24.33Gbps for CPRI options 7 and 8) |
| Form Factor | SFP28, hot pluggable |
| Optical Technology | DWDM, single channel per module |
| Channel Plan | 100GHz C-band grid (50GHz builds on request) |
| Reach | 10km and 40km over SMF, longer with amplification |
| Fiber Type | Single Mode Fiber (SMF) |
| Connector Type | LC duplex |
| Receiver | PIN (10km grade), APD (40km grade) |
| DDM / DOM | Supported |
| Supply Voltage | 3.3V |
| Compliance | SFP28 MSA, ITU 100GHz 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.
| ITU channel | Center wavelength | Common use |
|---|
| CH 20 | 1561.42nm | First channel on a standard 25G plan |
| CH 25 | 1557.36nm | Metro 25G add drop |
| CH 30 | 1553.33nm | Metro 25G add drop |
| CH 35 | 1549.32nm | Regional 25G span |
| CH 40 | 1545.32nm | Regional 25G span |
| CH 45 | 1541.35nm | Amplified 25G span |
| CH 50 | 1537.40nm | Amplified 25G span |
| CH 55 | 1533.47nm | High channel count plan |
| CH 60 | 1529.55nm | High channel count plan |
Applications
Metro and Regional 25G Transport
Carries each 25G service on its own dense channel so one fiber pair covers a whole route instead of a single link.
Amplified 25G Spans
Extends 25G reach beyond the module grade with an inline amplifier on routes where a regenerator would cost more.
Fronthaul and Mid Haul Capacity
Lets several radio sites or sectors share a cable that is already carrying traffic, using spare C-band channels.
Compatibility
25G DWDM modules are coded for the transport, fronthaul or routing platform you name and tested on live ports before shipment. The channel plan is the critical detail, so we ask for the existing channel list, the mux/demux part, the measured span and whether amplifiers are in line, then match wavelength, grade and patch cords to that plan.
Related Products
Frequently Asked Questions
When should I use 25G DWDM instead of CWDM?
DWDM gives far more channels on the same fiber and supports amplified spans, so it fits routes with heavy traffic or long distances. CWDM stays the cheaper option where 18 channels or fewer are needed within 40km.
Do I need an APD receiver for 25G DWDM?
The APD version adds sensitivity for longer spans and routes with high loss or several mux stages. On short amplified runs the standard PIN grade at 10km is usually enough.
Can a 25G DWDM channel share a plan with 10G and 100G channels?
Yes. The plan is defined by the grid and channel numbers, so different line rates can occupy different channels on the same fiber as long as the mux hardware passes those wavelengths.
Is a tunable alternative available?
Where a plan changes often, a tunable module avoids stocking several fixed channels. Tell us the route and the planned channels and we will confirm what fits.
Why Choose Apex
- Optical engineering support and supply from 1.25G to 800G, including DWDM, CWDM and single fiber lines.
- Channel plan, mux hardware and span budget checked before the order is released.
- Every module is tested for optical power, wavelength and error rate before shipment.
- Backed by a 3 year warranty and technical support before and after the sale.
