Optical Transceiver Module
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    Brocade XBR-G6MIDR12PTPOD-32G BR-MIDRMFEB-01-Z software license for HD-G620-24-32G switch

    Brand Brocade License PN XBR-G6MIDR12PTPOD-32G License Inside PN  BR-MIDRMFEB-01-Z Place of origin Malaysia Form Factor F/S Inside SFP:8pcs 32G 850nm SW Active Brocade HD-G630-48-32G switch Low End Case Temperature (°C) 0°C High End Case Temperature (°C) 70°C Diagnostics Digital Transmitter VCSEL Receiver PIN Voltage Supply 3.3--5v Connector Dual LC Warranty 1 year Condition new DDMI Yes Time of delivery  Within 24 hours Package Brocade original package

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  • G720-64-32G-F Fiber Optical Switch
    24/64 ports Brocade G720 Switch G720-64-32G-F Fiber Optical Switch

    The Brocade G720 Switch is a Gen 7 switch with 64 ports in an ultra-dense 1U design. Delivering unmatched 64G performance and 50% lower latency compared to the previous generation, this switch delivers a fixed-port building block designed to maximize the performance of flash and NVMe environments to meet demanding workloads. With Brocade Gen 7 technology, the Brocade G720 delivers far more than just speed and latency improvements. It can eliminate the pain of managing your data center, with autonomous SAN technology to deliver a network that can self-learn, self-optimize, and self-heal without intervention.

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  • QDD-400G-ZRP-S
    Compatible QDD-400G-ZRP-S 400G ZRP Optical Transceivers

    Product Description This MSA compliant QSFP-DD transceiver provides 400GBase-ZR Open ZR+ throughput over Single-mode fiber (SMF) using a coherent wavelength and using an LC connector. It is built to MSA standards and is uniquely serialized and data-traffic and application tested to ensure that they will integrate into your network seamlessly. Digital optical monitoring (DOM) support is also present to allow access to real-time operating parameters. This transceiver is Trade Agreements Act (TAA) compliant. We stand behind the quality of our products and proudly offer a limited lifetime warranty. ProLabs’ transceivers are RoHS compliant and lead-free. TAA refers to the Trade Agreements Act (19 U.S.C. & 2501-2581), which is intended to foster fair and open international trade. TAA requires that the U.S. Government may acquire only “U.S. – made or designated country end products.

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  • SFP 1.25G FR 15km
    Compatible Mikrotik XS+2733LC15D SFP 1.25G FR Single Mode 1270nm+ 1330nm 15km Optical Transceivers

    Kit contains two SFP+ modules that can be used as a pair to achieve operating data rate up to 25 Gbps for distances up to 15km on a single optical cable. SFP/ SFP+/ SFP28 Units are tested and compatible with RB260GS,RB2011LS, RB2011LS-IN, RB2011UAS-IN, RB2011UAS-RM, RB2011UAS-2HnD, RB2011UAS-2HnD-IN, and CCR1036-12G-4S. Units are compatible with non-MikroTik SFP devices as well. Details Product code XS+2733LC15D Connector Single LC UPC Data Rate 1G / 10G / 25G Distance 15 km Format SFP / SFP+ / SFP28 Mode Single mode Wavelength 1270nm + 1330nm

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  • QSFP+ 10G SR 15km
    Compatible Mikrotik XS+2733LC15D 10G QSFP+ SR Optical Transceivers

    Kit contains two SFP+ modules that can be used as a pair to achieve operating data rate up to 25 Gbps for distances up to 15km on a single optical cable. SFP/ SFP+/ SFP28 Optical Transceivers

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  • BR6505-24-8G-R/BR6505-24-16GR/BR6505-24-16GR/6505-24-0-R
    12/24 Ports Compatible Brocade BR6510 Gen 5 Fiber Channel 1U Switch BR6510-24-8G-R/BR6510-24-16GR/BR6510-24-16GR/6505-24-0-R Fiber Optical Switch Suitable For 57-1000117-01/57-1000027-01/57-0000080-01/57-0000088-01/57-0000089-01

    12/24 Ports Compatible Brocade BR6510 Gen 5 Fiber Channel 1U Switch BR6510-24-8G-R/BR6510-12-8GR/BR6510-24-8GR Fiber Optical Switch Suitable For 57-1000117-01/57-1000027-01/57-0000080-01/57-0000088-01/57-0000089-01/57-1000487-01/57-0000089-01/57-1000488-01/57-1000262-01/57-1000489-01/XBR-000458/XBR-000258/XBR-000499/XBR-000498

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QSFP-40G-LR4 Transceiver: QSFP+ CWDM vs PSM

2021 / 02 / 05

QSFP-40G-LR4 Transceiver: QSFP+ CWDM vs PSM

QSFP+ transceiver, the updated version of QSFP (Quad Small Form-Factor Pluggable), is known by providing four 10-Gigabit transmit and receive channels in a single pluggable optical module for an aggregate bandwidth of 40 Gbps. It’s nowadays widely adopted to provide high-density and low-power 40 Gigabit Ethernet connectivity. Based on the root of QSFP+ transceiver, types of 40G transceivers have been bred, such as QSFP+ 40G LR4 CWDM and 40G PSM LR4. In this post, a comparison between QSFP 40G LR4 CWDM and 40G LR4 PSM will be explored.

CWDM and PSM Basics

Before the comparison, it’s necessary to go through some basics of CWDM and PSM:

CWDM (Coarse Wavelength Division Multiplexing): As one type of WDM, CWDM is used to combine multiple signals on laser beams at various wavelengths for transmission along with fiber optic cables. It is typically deployed in point-to-point topology in enterprise networks and telecom access networks.

PSM (Parallel Single Mode Fiber): It is a technology that enables signals transmitted or received over four parallel fibers in each direction rather than over multiple channels on a single fiber.

QSFP-40G-LR4 CWDM Transceiver

QSFP-40G-LR4 CWDM transceiver commonly refers to the QSFP+ 40G LR4 transceiver. With a duplex LC interface, QSFP+ CWDM LR4 is compliant to 40GBASE-LR4 of the IEEE P802.3ba standard. It contains four unbiased transmit and receive channels, with each channel carrying a 10G optical transmission. The maximum transmission distance of this QSFP+ transceiver type is 10 km. To minimize the optical dispersion in the long-haul system, the single mode fiber (SMF) has to be used.

This QSFP-40G-LR4 CWDM transceiver works by converting 4 input channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and then multiplexes them into a single channel for 40G optical transmission, propagating out of the transmitter module from the SMF. Reversely, the receiver module accepts the output of 40G QSFP CWDM optical signal and demultiplexes it into four 10G separate channels with different wavelengths.


The central wavelengths of the 4 CWDM channels are 1271, 1291, 1311 and 1331 nm, which comply with CWDM wavelength grid defined by ITU-T G694.2. Each wavelength channel is collected by a discrete photodiode and output as electric data after being amplified by a trans-impedance amplifier (TIA).

QSFP-40G-LR4 PSM Transceiver

QSFP-40G-LR4 PSM is also named as QSFP-40G-PLR4 by some vendors like  TOPSTAR. Equipped with an MTP/MPO fiber ribbon interface, the LR4 PSM QSFP+ transceiver offers 4 independent transmit and receive lanes, each capable of 10G operation up to 10 km over single mode fiber.

QSFP-40G-LR4 PSM works in a way that the transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. Then the receiver module converts parallel input signals via a photodetector array into output signals. The output signals of the receive module are also voltage compatible with CML levels. Usually, there are guide pins inside the MTP/MPO interface receptacle for proper channel to channel alignment. In that case, when users plug an optical cable with the MTP/MPO connector into a QSFP+ transceiver receptacle, the cable cannot be twisted in case of alignment failure.


QSFP-40G-LR4 CWDM vs. PSM: What’s the Difference?

As 40G QSFP+ transceivers, both 40G LR4 CWDM and PSM are used for long-distance transmission. However, in the aspects of optical transmitter (optical Tx), optical MUX/DEMUX, interface, and fiber, they have different features as listed in the following table.




Optical Tx

4 uncooled 1300nm CWDM directly-modulated lasers (20nm wavelength spacing)

4 integrated silicon photonic modulators and one CW laser (uncooled 1300nm DFB laser)





Duplex LC

MTP/MPO fiber ribbon


2 single-mode fibers

8 single-mode fibers



Can QSFP-40G-LR4 CWDM and PSM Transceivers Be Used for 4x10G?

It depends on your QSFP+ transceiver type. When you use the QSFP-40G-LR4 CWDM transceiver, it cannot be split into 4x10G. That’s because it uses 4 wavelengths on a pair of single mode fiber with LC duplex interface, and does not allow itself to split into 4 pairs without substantial complexity to split out the wavelengths. However, if you use a QSFP-40G-LR4 PSM transceiver, the answer will be different. 40GBASE-LR4 PSM QSFP+ transceiver can be used for 4x10G, because it uses parallel (ribbon) fiber with MTP/MPO interface, which allows the creation of 4 fiber pairs.

What’s the Difference Between QSFP+ PSM IR4 and 40G QSFP+ PSM LR4 Transceivers?

These two QSFP+ transceivers are both the integrated four-channel optical transceivers with MTP/MPO fiber ribbon interfaces. The only difference lies in their supported transmission distance. 40G PSM LR4 is used to support a transmission distance no further than 10 km while 40G PSM IR4 is 1.4 km.


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