40G QSFP+ Transceiver Selection Guide
A 40G QSFP+ transceiver selection guide must begin with the complete link requirement, rather than simply the maximum transmission distance. First, match the module to the installed OM3, OM4 or OS2 fibre. Next, confirm whether the channel uses MPO/MTP or duplex LC connectivity. Then, verify the host equipment, optical-power window and any 4 × 10G breakout requirement. This guide works through each decision using only the Yamasaki 40G QSFP+ transceivers available from Anderson Corporation.
Although a module’s label may include “40G”, choosing it on that basis alone can create an incompatible link. For example, two products may support the same distance over OS2 fibre while using different connectors and optical architectures. Likewise, an MPO/MTP plug may fit a module physically. However, the link will still fail if the fibre type, connector gender, polarity or lane arrangement is incorrect.
Therefore, treat transceiver selection as a complete system decision. Ultimately, the host ports, modules, fibre channel and far-end interface must all work together.
If you first need a broader explanation of the module, its terminology and its role within a 40 Gigabit Ethernet link, read What Is a 40G QSFP+ Transceiver? before continuing with the selection process.
What Information Do You Need Before Selecting a 40G QSFP+ Transceiver?
Before considering a product code, first collect the following information:
- Required transmission distance
- Installed or proposed fibre category: OM3, OM4 or OS2
- Connector arrangement: MPO/MTP or duplex LC
- Number of available fibres
- Existing patch panels, cassettes, adaptors and trunks
- Equipment manufacturer and exact host model at each end
- Line-card, network-adaptor or port details
- Operating-system or firmware version
- Required operating temperature
- Complete channel-loss information
- Optical interface at the far end
- Whether the port must operate as native 40G or 4 × 10G breakout
If the project involves existing infrastructure, also obtain current test results wherever possible. Although a cable label and route drawing provide useful starting information, neither confirms that the installed channel will support the proposed 40G interface. Therefore, review the available test evidence before selecting the appropriate Yamasaki 40G QSFP+ transceiver.
Quick 40G QSFP+ Transceiver Selection Guide Product Selection Table
The table below provides an initial direction within the Anderson Corporation range. It does not replace confirmation against the exact Yamasaki datasheet and host-equipment requirements.
| Network requirement | Yamasaki option | Fibre | Connector | Maximum supported reach | Breakout position |
|---|---|---|---|---|---|
| Standard short multimode link | 40GBASE-SR4 | OM3 or OM4 | MPO/MTP | 100 m over OM3; 150 m over OM4 | Commonly suitable, subject to host and channel support |
| Extended multimode link | 40GBASE-eSR4 | Multimode, subject to confirmation | MPO/MTP | 300 m | Confirm the exact optical implementation and host support |
| Parallel OS2 link | PSM4 2 km | OS2 | MPO/MTP | 2 km | Do not assume; confirm the complete breakout design |
| Long parallel OS2 link | PSM4 10 km | OS2 | MPO/MTP | 10 km | Do not assume; confirm the complete breakout design |
| Duplex LC across supported multimode or OS2 | Universal | Supported multimode or OS2 | Duplex LC | 100 m over multimode; 2 km over OS2 | No passive 4 × 10G optical breakout |
| Medium-reach duplex OS2 link | LR4Lite | OS2 | Duplex LC | 2 km | No passive 4 × 10G optical breakout |
| Long duplex OS2 link | 40GBASE-LR4 | OS2 | Duplex LC | 10 km | No passive 4 × 10G optical breakout |
| Extended duplex OS2 link | 40GBASE-ER4 | OS2 | Duplex LC | 40 km | No passive 4 × 10G optical breakout |
Maximum reach means the maximum supported channel distance under the applicable product conditions. It does not guarantee operation across every channel of that length. Connector loss, splice loss, fibre attenuation, contamination, modal performance and engineering margin still matter.
Step 1: Establish the Required Transmission Distance
Distance provides the first filter. However, it should never determine the final selection by itself. First, measure the complete optical route between the transceiver interfaces rather than relying on the straight-line distance between buildings or equipment rooms.
Up to 100 metres
For a compatible OM3 MPO/MTP channel, 40GBASE-SR4 provides the standard initial direction because it supports distances up to 100 metres over OM3.
The same SR4 module supports up to 150 metres over OM4. Therefore, identify the actual multimode fibre category rather than recording the pathway only as “multimode”.
Where the installed pathway uses duplex LC connectivity, SR4 is not suitable. Instead, a supported Universal module may provide an option across qualifying multimode infrastructure up to 100 metres. Nevertheless, confirm its complete fibre and channel requirements before ordering.
From 100 to 150 metres
An OM4 MPO/MTP pathway may support 40GBASE-SR4 up to 150 metres. However, OM3 does not gain the same reach simply because it connects to the same module.
Consequently, confirm that the complete channel uses OM4 components, including the permanent cabling, patch leads and any cassette components. If the multimode infrastructure is mixed or undocumented, carry out a closer assessment before selecting the module.
Multimode links approaching 300 metres
For longer parallel multimode links, the Yamasaki 40GBASE-eSR4 model supports a maximum reach of 300 metres over OM3 through MPO/MTP connectivity.
However, do not assume that every eSR4 product from every manufacturer provides identical OM3 and OM4 distances. Furthermore, do not assume that a legacy 300-metre multimode pathway will qualify automatically. Instead, review its modal performance, insertion loss and the condition of the installed components.
OS2 links up to 2 kilometres
For OS2 links up to 2 kilometres, the Anderson Corporation range provides three possible directions. However, the correct choice depends on the installed fibre and connector architecture:
- PSM4 2 km for parallel OS2 infrastructure with MPO/MTP connectivity
- LR4Lite for duplex OS2 infrastructure with LC connectivity
- Universal for a supported duplex OS2 channel up to 2 km
Although these products share a nominal 2 km reach, they are not interchangeable. PSM4 uses eight active singlemode fibres, whereas LR4Lite and Universal use two fibres and wavelength multiplexing. Therefore, the existing connector arrangement and available fibre count will usually narrow the selection immediately.
OS2 links up to 10 kilometres
For OS2 MPO/MTP infrastructure, the Yamasaki PSM4 10 km module provides the parallel-optics option. In contrast, conventional duplex OS2 infrastructure can use 40GBASE-LR4 for distances up to 10 km through duplex LC connectivity.
Again, matching the transmission distance does not establish interoperability. For example, a PSM4 module at one end cannot connect directly to an LR4 module at the other. Their optical architectures, connectors and lane arrangements are fundamentally different.
OS2 links up to 40 kilometres
For longer duplex OS2 routes, 40GBASE-ER4 supports links up to 40 km. However, select ER4 only when the route genuinely requires its extended reach and optical budget.
On a short or very low-loss OS2 channel, the receiver may receive excessive optical power. Therefore, check the maximum receiver input as well as the receiver sensitivity. If the predicted receive level is too high, the design may require a correctly specified optical attenuator.
Step 2: Identify OM3, OM4 or OS2 Fibre
After establishing the distance, identify the fibre category. The installed fibre determines which optical system can operate across the channel. However, fibre category alone does not complete the selection because the connector architecture and available fibre count must also match.
OM3 multimode fibre
OM3 supports the Yamasaki 40GBASE-SR4 module for qualifying links up to 100 metres. In this configuration, the channel uses parallel optics through an MPO/MTP interface and eight active fibres.
If the link exceeds 100 metres, do not extend the assumed SR4 reach. Instead, assess whether the Yamasaki eSR4 module and the complete OM3 channel meet the applicable requirements. The Yamasaki eSR4 model supports up to 300 metres over OM3, subject to the complete channel complying with its specifications.
OM4 multimode fibre
OM4 supports 40GBASE-SR4 links up to 150 metres under the applicable channel conditions. Because OM4 provides greater modal bandwidth, it achieves a longer standard SR4 reach than OM3.
Nevertheless, an OM4 cable designation does not overcome excessive insertion loss, contamination or poor connector performance. Therefore, the completed pathway must still satisfy the applicable 40G channel requirements.
Furthermore, do not assume an extended eSR4 reach over OM4 unless the exact Yamasaki product specification confirms it. A distance published for another manufacturer’s eSR4 module should not be applied automatically.
OS2 singlemode fibre
OS2 supports two different optical architectures within the Yamasaki range:
- PSM4 uses parallel singlemode fibres and MPO/MTP connectivity.
- Universal, LR4Lite, LR4 and ER4 use wavelength multiplexing and duplex LC connectivity.
Therefore, recording only “OS2” leaves the selection incomplete. You must also confirm the number of available fibres, the connector architecture and the required transmission distance.
Once these details are established, review the complete Yamasaki 40G QSFP+ transceiver range to identify the products that match the proposed infrastructure.
Step 3: Choose MPO/MTP or Duplex LC Connectivity
Connector type is not a cosmetic preference. Instead, it reflects how the module transports its optical lanes. Therefore, you must match the connector architecture to the selected transceiver technology.
This connector decision reflects the module’s underlying optical architecture. Therefore, understanding how 40G QSFP+ transceivers work will help explain why parallel-optics products use MPO/MTP connectivity, while wavelength-multiplexed products use duplex LC connectivity.
When does MPO/MTP suit the design?
MPO/MTP connectivity suits the following Yamasaki parallel-optics products:
- 40GBASE-SR4
- 40GBASE-eSR4
- PSM4 2 km
- PSM4 10 km
These modules use four transmit fibres and four receive fibres. Consequently, a common 12-position MPO/MTP interface uses eight active fibre positions during native 40G operation.
Before selecting an MPO/MTP product, confirm:
- Multimode or singlemode construction
- Fibre count
- Connector gender
- Guide-pin arrangement
- Key orientation
- Polarity
- Active lane mapping
- Cassette and adaptor configuration
- Connector cleanliness and condition
Although an MPO/MTP connector may fit physically, it can still have the wrong fibre type, gender, polarity or lane arrangement. Accordingly, verify the complete fibre assembly rather than relying on the connector name alone.
When does duplex LC suit the design?
Duplex LC connectivity suits the following wavelength-multiplexed Yamasaki products:
- Universal
- LR4Lite
- 40GBASE-LR4
- 40GBASE-ER4
Instead of allocating each optical lane to a separate fibre, these products transmit multiple wavelengths through one fibre. Meanwhile, a second fibre carries the return traffic. As a result, they require only two active fibres.
Duplex LC often provides the natural direction when an existing OS2 backbone presents conventional LC patching. In addition, it uses fibre more efficiently than an eight-fibre parallel channel. Nevertheless, the design must still control Tx-to-Rx polarity, connector cleanliness and total optical loss.
Most importantly, a passive cassette cannot convert one optical architecture into another. For example, an MPO/MTP-to-LC cassette does not transform SR4 into LR4. Likewise, it cannot combine four parallel optical lanes into wavelength-multiplexed transmission.
Step 4: Assess the Existing Fibre Infrastructure
After identifying the required connector architecture, assess the existing fibre infrastructure from end to end. A strong 40G QSFP+ transceiver selection guide should prioritise infrastructure reuse only when the installed channel genuinely qualifies.
Where suitable infrastructure already exists, reuse can reduce project cost, installation work and service disruption. Conversely, forcing an unsuitable pathway to support 40G can increase commissioning risk, troubleshooting time and overall project cost.
The Yamasaki range includes options for qualifying parallel-fibre and duplex-fibre infrastructure. However, the installed fibre category, connector arrangement and available fibre count must still match the selected module. Therefore, review the complete Yamasaki 40G QSFP+ transceiver range alongside the verified characteristics of the existing channel.
Review the infrastructure from end to end:
- First, confirm the permanent cable’s fibre category.
- Next, verify every patch lead, cassette and adaptor component.
- Then, record the total optical route length.
- In addition, count all connectors, adaptors and splices.
- Where applicable, check MPO/MTP gender, key orientation and polarity.
- Inspect and clean every accessible connector end face.
- Review previous test records and commissioning documentation.
- Finally, test the completed channel against the proposed 40G application.
Also consider the number of available fibres. For example, an OS2 route may support a distance of 10 km comfortably. However, if only one duplex pair is available, the infrastructure points towards LR4 rather than PSM4. In contrast, an existing OS2 MPO/MTP trunk with eight correctly arranged fibres may support the parallel PSM4 architecture.
Future requirements should also influence the decision. If 4 × 10G breakout represents a genuine design objective, preserving access to the four parallel optical lanes may be important. Conversely, if fibre availability is limited, duplex wavelength-multiplexed optics may provide the stronger long-term direction.
Step 5: Confirm Host-Equipment Compatibility
A transceiver must satisfy both optical compatibility and host-equipment compatibility. Even when the fibre channel is designed correctly, the link cannot operate if the switch, router, server adaptor or appliance rejects the module or does not support the selected interface.
Therefore, before ordering, provide:
- Equipment manufacturer
- Exact chassis or appliance model
- Line-card or network-adaptor model
- Port number or port type, where relevant
- Operating-system or firmware version
- Required compatible coding
- Intended native 40G or 4 × 10G breakout mode
- Details of the equipment and transceiver at the far end
Anderson Corporation can arrange compatibility programming for many leading equipment platforms. However, support must be confirmed against the exact platform rather than assumed from the manufacturer’s name alone. In addition, the installed firmware, line card and port configuration may affect whether the host accepts and operates the module correctly.
Must both ends use the same module brand?
The two ends do not necessarily require modules with identical branding. However, each transceiver must suit its own host equipment. At the same time, the optical interfaces at both ends must interoperate across the complete fibre channel.
For example, both ends must use a compatible lane arrangement, wavelength plan, connector architecture and optical specification. Therefore, two modules do not become interoperable merely because both operate at 40G, use OS2 fibre or specify the same maximum reach.
Accordingly, confirm the module-to-host compatibility at each end separately. Then, confirm the optical compatibility between the two transceivers across the channel.
What if the host port is physically similar?
Physical fit does not prove electrical, software or operational support. Although some newer equipment ports may accept earlier QSFP-family modules in supported operating modes, the platform specification, firmware and port configuration ultimately govern operation.
Consequently, never order a transceiver solely from a photograph of the module cage or a broad equipment description. Instead, verify the exact host model, line card, port type, firmware version and intended operating mode before finalising the product selection.
Step 6: Check the Operating Environment
After confirming host compatibility, assess the environment in which the equipment and transceiver will operate. The module’s operating-temperature rating must suit the actual conditions surrounding the host equipment.
In particular, assess:
- Minimum and maximum ambient temperatures
- Expected internal equipment temperature
- Airflow around the module cage
- Rack loading and adjacent heat sources
- Indoor, outdoor-cabinet or industrial placement
- Humidity and condensation controls
- Dust and contamination exposure
- Vibration or mechanical disturbance
However, do not treat the published temperature limit as the normal design target. Instead, allow adequate operating margin for local hot spots, restricted airflow, seasonal changes and variations in equipment loading.
For example, a commercial-temperature module may suit a controlled data centre or equipment room. In contrast, an exposed telecommunications cabinet or industrial location may require a different environmental rating. Furthermore, the host equipment itself must support the same operating environment.
Therefore, confirm the required environmental rating against both the specific Yamasaki product and the exact host platform before ordering. Ultimately, a suitably rated transceiver cannot compensate for host equipment operating outside its approved environmental limits.
Step 7: Validate Optical Power and Channel Loss
Maximum distance offers a useful screening value. Optical power determines whether the completed channel can operate reliably.
At a basic level:
Available optical budget = minimum transmitter output − receiver sensitivity
The planned channel loss must account for:
- Fibre attenuation
- Connector and adaptor loss
- Splice loss
- MPO/MTP cassette or module loss
- Patch leads
- Measurement uncertainty
- Ageing and future repairs
- An appropriate engineering margin
For a parallel SR4 or PSM4 channel, assess every active lane. One high-loss fibre can prevent the complete 40G link from operating even when the average loss appears acceptable.
Why is receiver sensitivity not enough?
Receiver sensitivity represents the lowest specified receive level under the applicable conditions. It should not become the desired operating point. A link operating just above that limit has little resilience against contamination, movement, ageing or temperature changes.
Therefore, retain usable engineering margin after the planned channel loss.
Can the receiver receive too much power?
Yes. Maximum receiver input matters, particularly with extended-reach optics. Selecting ER4 simply because it can cover every shorter distance may overload a receiver on a low-loss route.
The predicted receive level should remain inside the complete operating window:
Receiver sensitivity ≤ predicted received power ≤ maximum receiver input
If the design falls outside either limit, choose a more suitable module or engineer the channel correctly. Do not add attenuation without first calculating and measuring the complete link.
Step 8: Decide Whether 4 × 10G Breakout Is Required
Some 40G QSFP+ ports can operate as four independent 10G interfaces. However, three elements must support the design:
- The host port must support 4 × 10G breakout mode.
- The transceiver must expose suitable independent optical lanes.
- The fibre assembly must route each transmit lane to the corresponding receive lane.
Within the Anderson Corporation range, 40GBASE-SR4 provides the clearest initial direction for conventional multimode optical breakout. An MPO/MTP-to-4 × duplex LC harness can route its four optical lanes towards four compatible 10G multimode interfaces, subject to the complete design.
Nevertheless, a fan-out lead does not create breakout capability. If the host supports only native 40G, the four branches will not become four operational ports.
Can LR4, LR4Lite, Universal or ER4 break out passively?
No. These modules combine four optical wavelengths internally onto a duplex fibre pair. A passive LC fan-out cannot separate that signal into four conventional 10G optical links.
Does every MPO/MTP module support breakout?
Do not assume so. PSM4 and eSR4 expose parallel lanes, but breakout requires confirmation of the module implementation, optical compatibility, host support and far-end 10G interfaces.
Therefore, state the breakout requirement before requesting a quotation. It can materially change the appropriate product and cabling arrangement.
40G QSFP+ Transceiver Selection Guide Directions Within the Yamasaki Range
The following summaries show where each available module initially fits. They are selection directions rather than substitutes for a final compatibility assessment.
40GBASE-SR4
Select SR4 as the initial direction for standard parallel multimode links:
- Up to 100 m over OM3
- Up to 150 m over OM4
- MPO/MTP connectivity
- Potential conventional 4 × 10G multimode breakout, subject to host support
Ordering code: QSFP+40G/SR4/01D
40GBASE-eSR4
Consider eSR4 for a qualifying extended multimode link:
- Maximum reach of 300 m
- MPO/MTP connectivity
- Fibre category and complete channel subject to confirmation
- Breakout capability not to be assumed
Ordering code: QSFP+40G/eSR4/03D
PSM4 2 km
Select PSM4 2 km where the site has parallel OS2 infrastructure:
- Up to 2 km
- OS2 singlemode fibre
- MPO/MTP connectivity
- Eight active fibres
Ordering code: QSFP+40G/PSM4/2D
PSM4 10 km
Select PSM4 10 km where a long parallel OS2 channel is required:
- Up to 10 km
- OS2 singlemode fibre
- MPO/MTP connectivity
- Eight active fibres
Ordering code: QSFP+40G/PSM4/10D
Universal
Consider the Universal module for approved duplex LC pathways:
- Up to 100 m over supported multimode fibre
- Up to 2 km over OS2
- Duplex LC connectivity
- Exact multimode and channel requirements subject to confirmation
- No passive 4 × 10G optical breakout
Ordering code: QSFP+40G/UNI/2D
LR4Lite
Select LR4Lite for a medium-reach duplex OS2 link:
- Up to 2 km
- OS2 singlemode fibre
- Duplex LC connectivity
- Two active fibres
- No passive 4 × 10G optical breakout
Ordering code: QSFP+40G/LR4Lite/2D
40GBASE-LR4
Select LR4 for a recognised long-reach duplex OS2 interface:
- Up to 10 km
- OS2 singlemode fibre
- Duplex LC connectivity
- Two active fibres
- No passive 4 × 10G optical breakout
Ordering code: QSFP+40G/LR4/10D
40GBASE-ER4
Select ER4 only where the engineered duplex OS2 route requires extended reach:
- Up to 40 km
- OS2 singlemode fibre
- Duplex LC connectivity
- Two active fibres
- Minimum and maximum receive power require careful assessment
- No passive 4 × 10G optical breakout
Ordering code: QSFP+40G/ER4/40D
40G QSFP+ Transceiver Selection Guide – Common 40G QSFP+ Selection Mistakes
Avoid these frequent errors:
- Choosing the longest-reach module as the safest option
- Treating all 2 km or 10 km products as interchangeable
- Recording fibre only as “multimode” or “singlemode”
- Assuming an MPO/MTP connector proves multimode operation
- Ignoring connector gender, polarity or lane mapping
- Assuming every duplex LC module supports passive breakout
- Assuming a breakout harness enables an unsupported host mode
- Selecting from distance without calculating optical loss
- Ignoring maximum receiver input on short extended-reach links
- Assuming the module will work because it fits the host cage
- Omitting the far-end equipment and transceiver from the assessment
- Applying another manufacturer’s reach specification to a Yamasaki model
The IEEE 802.3 Ethernet Working Group defines recognised Ethernet physical interfaces, including standard 40G architectures. However, extended-reach and industry-defined products may have implementation-specific requirements. Therefore, always use the exact product specification when confirming reach and interoperability.
40G QSFP+ Transceiver Selection Guide Checklist
Before placing an order, verify each item:
- Required transmission distance confirmed
- Fibre identified as OM3, OM4 or OS2
- Fibre count confirmed
- MPO/MTP or duplex LC connector confirmed
- MPO/MTP gender and polarity confirmed where applicable
- Existing pathway inspected and tested
- Host manufacturer and exact model supplied
- Line-card or network-adaptor details supplied
- Firmware or operating-system version checked
- Compatible coding confirmed
- Far-end optical interface confirmed
- Native 40G or 4 × 10G operating mode confirmed
- Operating-temperature requirement confirmed
- Channel-loss budget calculated
- Maximum receiver input checked
- Engineering margin retained
- Exact Yamasaki datasheet reviewed
Frequently Asked Questions – 40G QSFP+ Transceiver Selection Guide
Which 40G QSFP+ transceiver should I use over OM3?
For a standard OM3 MPO/MTP link up to 100 metres, Yamasaki 40GBASE-SR4 provides the initial product direction. Longer multimode links require assessment against the eSR4 specification and complete channel conditions.
Which 40G QSFP+ transceiver should I use over OM4?
Yamasaki 40GBASE-SR4 supports up to 150 metres over OM4 through MPO/MTP connectivity. Confirm the complete channel as OM4 and ensure it meets the required loss and performance limits.
Which Yamasaki modules use OS2 fibre?
The range includes PSM4 2 km and 10 km modules for OS2 MPO/MTP infrastructure. Universal, LR4Lite, LR4 and ER4 support applicable OS2 links through duplex LC connectivity.
Can I choose a module from distance alone?
No. Fibre category, connector type, available fibre count, optical architecture, loss budget, host compatibility and breakout requirements must also align.
Can an MPO/MTP-to-LC cassette make SR4 work over duplex fibre?
No. A passive cassette can rearrange fibre connections, but it cannot convert four parallel SR4 lanes into a wavelength-multiplexed duplex optical signal.
Does the longest-reach module provide the safest choice?
No. An extended-reach module can create excessive receiver power on a short, low-loss channel. Select the interface whose complete optical window suits the engineered route.
Can a 40G QSFP+ transceiver connect to four 10G links?
SR4 can support many conventional 4 × 10G multimode breakout designs. However, the host port, transceiver, fibre assembly and far-end interfaces must all support the arrangement.
Can Anderson Corporation provide compatibility programming?
Anderson Corporation can arrange compatibility programming for many leading equipment platforms. Supply the exact equipment, line-card and firmware details so compatibility can be assessed before ordering.
Conclusion – 40G QSFP+ Transceiver Selection Guide
This 40G QSFP+ transceiver selection guide shows why the correct decision depends on the complete network channel. First, establish the required distance and fibre category. Next, confirm whether the channel uses MPO/MTP or duplex LC connectivity. At the same time, assess the available fibre count and existing infrastructure. Then, verify host compatibility, operating conditions and optical power requirements. Finally, determine whether the application requires 4 × 10G breakout support.
Within the Yamasaki range, SR4 and eSR4 support applicable parallel multimode links, while PSM4 supports parallel OS2 pathways. Meanwhile, Universal, LR4Lite, LR4 and ER4 serve qualifying duplex LC applications across supported multimode or OS2 infrastructure. However, each option has a defined role. Therefore, you should never select a transceiver based on reach alone.
For a final product and compatibility assessment, provide Anderson Corporation with the equipment models at both ends, firmware details, fibre category, connector arrangement and complete channel distance. In addition, include available loss information and any 4 × 10G breakout requirement. Once these details are confirmed, explore the complete Yamasaki 40G QSFP+ transceiver range or request assistance with identifying the correct configuration.