5G Fronthaul WDM technology will be important as global 5G networks scale and eventually new network topologies become popular such as 5G C-RAN (centralized RAN). 5G Mobile Networks necessitates massive investment in much denser radio networks and many new cells, which require the deployment of new optical CPRI fronthaul networks. Let’s take a step back and consider what makes 5G so unique? 5G mobile networks offer higher quality of service, lower latency, and greater bandwidth, which improves user experience and opens up a variety of new use cases. For 5G Fronthaul WDM – smart usage of colored eCPRI 25G optical transceivers and passive WDM technologies can achieve great savings and maximum efficiency of existing fibers. Mixture of colored transceivers and Passive WDM Technology is excellent choice, as it’s flexible, enables many network topologies, it’s protocol and bit rate agnostic and eliminates need for independent power supplies. Passive WDM can help not only in fronthaul and backhaul in 5G, but also has a great potential in industrial class networks used in such industries as Manufacturing, Oil & Gas, Mining, Power etc.

Just Right 5G Fronthaul WDM Technology:

5G Fronthaul WDM passive networks have straight-forward requirements – carry as much as possible 25G (CPRI option 10) services over one or two fiber connections and possibility to install fully passive units in outdoor environment – respectively IP65 -40 to 85C industrial temperature. For many years two most popular passive WDM technologies are CWDM (18 wide-band lambdas) and DWDM (45 narrow-band lambdas). However, when comes to 25G Services and CWDM, we can use only 12 from available 18 wavelengths, as there is too high dispersion in some regions of CWDM spectrum.

On other hand, when it comes to passive DWDM (5G DWDM scenario), all 45 channels are available for 25G Services, but cost of transceivers are much higher and then there is a problem with thermal stability. If we want use 20+ channel systems of DWDM – then traditional TTF Filter technology will bring a lot of attenuation, but AAWG Filter technology is not fit for industrial temperatures, if it’s truly passive.

Our approach uses legacy CWDM technology and new-comer in block – LWDM. LWDM technology offers 12 narrow-band wavelengths, perfectly fitting in 1260 – 1320 nm window and compromising only 3 from available 12 CWDM channels. Both, CWDM and LWDM technologies combined deliver us high capacity of 21 channels for passive systems and features low transceiver cost and industrial temperature resistance.

5G Fronthaul WDM at a glance:

5G Fronthaul WDM – Flexible Topologies & Scenarios:

# Scenario #1 – Double Fiber Passive CWDM:

Industrial Double Fiber Passive CWDM scenario consist of DCMD-12I and DCMD-12 filter units which support up to 12 service independent channels using 1271-1371nm and 1471-1571nm wavelength from ITU-T G.694.2 grid. Industrial DCMD-12I unit is designed for harsh outdoor environments supporting IP65 water, dust resistance, -40 to 85C industrial temperature, telecom pole or wall installation options and comes with ODVA Dual LC connectors for easy fiber connection. Standard DCMD-12 unit is deployed in 1U 19-inch telecom subrack. Depending on the desired networking scenario we can interconnect two Industrial DCMD-12I filters or two 1U Standard DCMD-12 filters or can connect a Standard DCMD-12 filter with an Industrial DCMD-12I filter.

# Scenario #2 – Single Fiber Passive CWDM:

Industrial Single Fiber Passive CWDM scenario consist of A side and B side filter units: SCMD-6A, SCMD-6AI and SCMD-6BI which support up to 6 service independent channels over single fiber using 1271-1371nm and 1471-1571nm from ITU-T G.694.2 wavelength grid. SCMD-6AI and SCMD-6BI units are for harsh environments supporting IP65 water, dust resistance, -40 to 85C industrial temperature, telecom pole or wall installation options and comes with ODVA LC connectors for easy fiber connection while SCMD-6A is LGX type B module installed in standard 19-inch 1U telecom sub-rack. We can connect two Industrial A and B side units: SCMD-6AI with SCMD-6BI or can connect A side: SCMD-6A with Industrial B side: SCMD-6BI depending on desired networking scenario.

# Scenario #3 – Double Fiber Passive Hybrid WDM:

Industrial Double Fiber Passive Hybrid WDM scenario consist of DHMD-21, DCMD-9I and DLMD-12I CWDM and LWDM (LAN-WDM) filter units which when used together provide bus networking topology. 21 Channel Hybrid DHMD-21 is deployed in the main site and is installed in 1U standard 19-inch telecom subrack. DHMD-21 connects to Industrial DCMD-9I (9 Channels CWDM filter unit) and through DCMD-9I upgrade port connects to Industrial DLMD-12I (12 Channels LAN-WDM filter unit). Both DCMD-9I and DLMD-12I can be deployed in harsh outdoor environments supporting IP65 water, dust resistance, -40 to 85C industrial temperature, telecom pole or wall installation options and comes with ODVA Double LC connectors for easy fiber connection.

# Scenario #4 – Single Fiber Passive Hybrid WDM:

Industrial Single Fiber Passive Hybrid WDM scenario consist of A side and B side SHMD-10A, SLMD-6BI and SCMD-4BI CWDM and LWDM (LAN-WDM) filter units, which when used together provide bus network topology design. 10 Hybrid Channel SHMD-10A unit is deployed in the main site and is installed in 1U standard 19-inch telecom sub-rack. SHMD-10A connects to Industrial SCMD-4BI (4 Channels CWDM filter unit) and through SCMD-4BI upgrade port connects to Industrial SLMD-6BI (6 Channels LWDM filter unit). Both SCMD-4BI and SLMD-6BI can be deployed in harsh outdoor environments supporting IP65 water, dust resistance, -40 to 85C industrial temperature, telecom pole or wall installation options and comes with ODVA Single LC connectors for easy fiber connection.

# Scenario #5 – 100G/40G Optical Junction Boxes:

Industrial 100G/40G Optical Junction Boxes are used for 100G QSFP28 to 4x25G SFP28 or 40G QSFP to 4x10G SFP+ signal splitting in harsh outdoor environments whenever extra flexibility during fiber installation and connection process is required. Installation becomes simpler because the optical feeder cable is connected directly to the Optical Junction Box and various length Optical Jumper Cables are available from the Junction Boxes to 25G SFP28 or 10G SFP+ interfaces.
There are 4 type of Optical Junction Boxes, where Industrial DCMD-4I has a built in CWDM filter supporting 1271nm, 1291nm, 1311nm, 1331nm wavelength and is designed for splitting 100G/40G CWDM4 signal into 4x25G or 4x10G CWDM signals, while DLMD-4I has a built in LWDM (LAN-WDM) filter supporting 1295.56nm, 1300.05nm, 1304.58nm, 1309.14nm wavelength and is designed for splitting 100G LAN-WDM signal into 4x25G lines. MSU-M4I and MSU-S4I are 12-Core MPO to 4 x LC Optical Junction Boxes where MSU-M4I is for Multi-Mode Fiber connections and MSU-S4I is for Single-Mode Fiber connections.
All Optical Junction Boxes can be deployed in harsh outdoor environments supporting IP65 water, dust resistance, -40 to 85C industrial temperature, telecom pole or wall installation options and comes with ODVA Double LC connectors for easy fiber connection.