JTOPTICS® 100G Transceivers and Cables

Posted byVijay Gupta21/06/20240 Comment(s)

 What 100G Transceivers and Cables are available from JTOPTICS?

JTOPTICS supports a full range of 100G copper cables and optical transceivers compliant to IEEE standards and industry MSAs. JTOPTICS’s 100G connectivity solutions include copper cables and Active Optical Cables (AOCs) to enable cost effective short reach options, as well as a wide range of optical transceivers in QSFP form factors for various fiber types, reach and interop requirements.


Product Number

Product Description

QSFP 100G Transceivers for parallel Multi-mode Fiber (MMF)


100G QSFP28 Transceiver 100GBASE-SR4 QSFP28 850nm 100m OM4 DOM MPO-12 Parallel MMF Optical Transceiver Module, 4x 25G-SR


100G QSFP28 Transceiver 100GBASE-PSM4 QSFP28 1310nm 2km DOM MTP/MPO-12 SMF Optical Transceiver Module


100G QSFP28 Transceiver 100GBASE-LR4 QSFP28 1310nm 10km DOM Duplex LC SMF Optical Transceiver Module


100G QSFP28 Transceiver 100GBASE-CWDM4 QSFP28 1310nm 2km DOM Duplex LC SMF Optical Transceiver Module


100G QSFP28 Transceiver 100GBASE-ER4 QSFP28 1310nm 40km DOM Duplex LC SMF Optical Transceiver Module

QSFP 100G Direct Attached Cable (DAC)


100G DAC Cable QSFP28 to QSFP28 passive twinax copper cable XX Meter 26AWG , Direct Attached Cable


100G DAC Cable QSFP28 to 4xSFP28 Breakout passive twinax copper cable XX Meter 30AWG , Direct Attached Cable

QSFP 100G Active Optical Cable (AOC)


100G AOC Cable QSFP28 to QSFP28 Active Optical Cable XX Meter OM3 Multimode cable


100G AOC Cable QSFP28 to 4xSFP28 Breakout Active Optical Cable XX Meter OM3 Multimode cable


What is the difference between QSFP28 and 100G QSFP?

They are the same. The “QSFP” form factor was originally defined for <10G speeds. When it was adopted for 40G, the name became QSFP+ to denote the higher aggregate performance. The same “QSFP” form factor was later adopted for 100G but the electrical interface had to be upgraded to handle 25Gbps/lane. The electrical interface for 100G can handle up to 28Gbps, hence the engineering and industry name is QSFP28. JTOPTICS refers to the 100G form factor as “100G QSFP” to avoid any confusion.


Which 100G QSFPs are capable of supporting link distances over 10km?

The JTOPTICS QSFP-100G-ZR4 supports link distances up to 80km. A minimum of 12dB attenuation is required to prevent permanent damage to the receiver - refer to the optics datasheet for optical specs. The QSFP-100G-ZR4 is supported on a limited set of platforms – refer to the Transceiver and Cable Guide for supported platforms.

The JTOPTICS QSFP-100G-ERL4 supports link distances up to 40km when the forward error correction (FEC) is enabled on the host switch / router. In the default no-FEC mode, QSFP-100G-ERL4 supports a reach of up to 30km. A minimum of ~10dB attenuation is required to guarantee the receiver is not damaged. Please refer to the optics datasheet for optical specifications.

The QSFP-100G-LR4 supports links up to 10km over duplex single mode fiber. Enabling FEC with QSFP-100G- LR4 optics on JTOPTICS switches can allow for links beyond 10km with single mode fiber. However, as this is not fully characterized, customers are advised to measure the link distance and optical loss budget before deploying.


What industry standards are associated with each of the 100G Transceivers and Cables?

The table below summarizes the JTOPTICS 100G transceivers and cables and the associated industry standards.

Product Number

Associated Industry Standard


IEEE 802.3 100GBASE-SR4


100G PSM4 MSA: http://psm4.org/


CWDM4 MSA: http://www.cwdm4-msa.org/


IEEE 802.3 100GBASE-LR4


Based on IEEE 802.3 100GBASE-LR4, with shorter reach. Compatible with LR4 up to 1km.


Based on IEEE 802.3 100GBASE-ER4, with reach up to 30km.


Are there any 100G transceivers that allow the use of standard duplex multi-mode fiber?

Yes – JTOPTICS offers two 100G transceivers that operate over duplex multimode fiber: The QSFP-100G-SWDM4, and the QSFP-100G-SRBD (or “BIDI”) transceiver.


What is the 100G SWDM4 transceiver?

The QSFP-100G-SWDM4 provides 100Gbps bandwidth over a standard duplex multi-mode fiber eliminating the need for expensive parallel multi-mode fiber infrastructure and offers a seamless migration path from duplex 10G/40G to 100G. It is supported on all JTOPTICS QSFP 100G ports and can be used for links up to 70m of OM3 fiber or up to 100m of OM4 fiber. The SWDM4 Tx port transmits 100G data over 4 x 25Gbps wavelengths, and the Rx port receives data over 4 x 25Gbps wavelengths. The wavelengths are in the “short wavelength” range (850nm – 940nm).


What is the 100G-SRBD (or “BIDI”) transceiver?

Like the QSFP-100G-SWDM4 transceiver described above, the JTOPTICS QSFP-100G-SRBD transceiver also provides 100Gbs bandwidth over standard duplex multi-mode fiber. However, unlike the SWDM4 transceiver (which transmits 4 x 25Gbps wavelengths out of the Tx port, and receives 4 x 25Gbps wavelengths on the Rx port), each optical port on the SRBD contains both a transmitter and receiver, running at full duplex 50Gb/s over a single fiber. The two ports of the QSFP-100G-SRBD provide an aggregate 100Gb/s of bandwidth. The QSFP- 100G-SRBD is supported on all JTOPTICS QSFP 100G ports, and can be used for links up to 70m of OM3 or up to 100m of OM4 multi-mode fiber.


Both the 100G-SWDM4 and the 100G-SRBD transceivers support 100G over duplex multi-mode fiber. When should each transceiver be used?

Both the 100G-SWDM4 and 100G-SRBD (sometimes called a “BIDI” transceiver) have been widely deployed within the industry, and share the same optical reach and fiber type (70m/100m over OM3/OM4 duplex MMF). However, the 100G-SWDM4 and 100G-SRBD do not interoperate with each other.

If interop with future 400G optics is a consideration, then the QSFP-100G-SRBD should be considered. The QSFP-100G-SRBD transceiver will interoperate with future JTOPTICS “400G-BIDI” transceivers. That is, an JTOPTICS OSFP-400G-SRBD or QDD-400G-SRBD transceiver will support breakout into 4x QSFP-100G-SRBD. The SWDM4 does not have a path for interop with future 400G optics.

The decision on which optic to will often depend on interop requirements. For example, for applications that require optical interop with third party 100G BIDI optics, the QSFP-100G-SRBD should be used.


Are JTOPTICS 100G Transceivers interoperable with other 100G transceivers available in the industry?

Yes, as long as the non-JTOPTICS 100G transceivers meet the associated industry standard specifications, JTOPTICS 100G transceivers are fully interoperable.


 Can 100G QSFP interfaces interoperate with SR10 based 100GbE?

No. The 100G QSFP form factor has just 4 electrical lanes, which is not enough to support 10 lanes of 10G electrical interface. A 100G QSFP can only support a 4x10G or 4x25G electrical interface, which can be used as 4x10GbE or 4x25GbE, but not 10x 10GbE.. As a result the 100G QSFP SR4 cannot interoperate with SR10 based 100GbE transceivers. A complex design with a reverse gearbox (4x25G to 10x10G) can achieve this but results in expensive and power hungry optics.


Can JTOPTICS 40G QSFPs be used in JTOPTICS 100G QSFP switch ports?

Yes, 40GbE QSFP+ transceivers will be detected and enabled upon insertion.


Are there any dual speed 100G/40G optics to avoid costly replacement when I upgrade?

The QSFP-100G-CWDM4 (up to 2km over duplex SMF) and QSFP-100G-PSM4 (up to 500m over parallel SMF), are dual-rate optics which be used in both 40G and 100G modes.


Which JTOPTICS 100G Transceivers and Cables can be used in breakout mode?

Breakout mode refers to running a 100G port as 4 separate channels of 25GE. Transceivers or copper cables that enable optical or electrical breakout allow one 100G QSFP100 port to connect to four physically separate 25G links. When breaking out a single 100G port to 4x 25G links, care must be taken to use the same Forward Error Correction (FEC) mode on both ends of the link to ensure link-up. JTOPTICS transceivers and copper cables that support 100G to 4x25G breakout are listed below.


Product Number

Supported Breakout modes

JT-100G-QSFP28-SR4 & JT-100G- QSFP28-XSR4

4x25G to interoperate with 25GBASE-SR. Care must be taken to use the same forward error correction (FEC) mode on both ends to link-up.


4x25G to interoperate with 25GBASE-LR up to 500m. Care must be taken to use the same forward error correction (FEC) mode on both ends to link-up.


What are “100G Lambda” Optics?

“100G Lambda” or “Single Lambda” optics are optical transceivers that have an optical output consisting of a single 100G PAM-4 optical signal. The JTOPTICS 100G “Single Lambda” SKUs are:

  • QSFP-100G-DR: 100GBASE-DR single lambda QSFP, up to 500m over duplex SMF.
  • QSFP-100G-FR: 100GBASE-FR single lambda QSFP, up to 2km over duplex SMF.
  • QSFP-100G-LR: 100GBASE-LR single lambda QSFP, up to 10km over duplex SMF.

The 100G-DR/FR/LR transceivers can be plugged into any JTOPTICS 100G QSFP port. The electrical connector interface is 4 x 25G NRZ – the same as all existing ‘legacy’ 100G QSFP modules. The optical output is a single wavelength (or “lambda”) 100Gbit/s PAM-4 optical signal. The 100G-DR/FR/LR modules include a gearbox chip to convert the 4 x 25G NRZ electrical signals to a 1 x 100G PAM-4 optical signal. This is in contrast to legacy QSFP100 modules (such as a CWDM4 or LR4 100G module), which have 4 x 25G NRZ optical wavelengths multiplexed onto one fiber.

Because of the different optical modulation scheme, 100G-DR / FR / LR modules will not interoperate with legacy 100G modules (such as CWDM4, LR4 etc), but they will interop with 400G-DR4 and 400G-XDR4 modules using breakout cables. Please refer to the 400G FAQ for more details about 400G to 4x 100G breakout options. The difference in optical modulation schemes between legacy 100G QSFP modules, and a 100G-DR / FR / LR module is illustrated below.





What optical fiber type is needed for 100G Transceivers?

The table below details the connector type of each 100G Transceiver and the cable type to be used.


Product Number

Optical Connector

Fiber Type to be used

QSFP-100G-SR4 / XSR4


(or MTP-12)

Parallel Multi-mode Fiber (MMF), OM3 or OM4


Duplex LC

Multi-mode Fiber (MMF), OM3 or OM4



(or MTP-12)

Parallel Single-mode Fiber (SMF)



Duplex LC

Single-mode Fiber


What Forward Error Correction (FEC) is required for JTOPTICS 100G Copper Cables?

For 100G QSFP to QSFP copper cables (CAB-Q-Q-100G-xM), Reed-Solomon RS FEC should be used to be compliant with the IEEE802.3 Ethernet specifications.

For 4x25G breakout applications using 100G QSFP to 4x 25G SFP breakout copper cables (CAB-Q-4S-100G- xM), the IEEE802.3 Ethernet specification includes 3 different 25G cables types (CA-N, CA-S and CA-L) which are aligned to 3 different loss classification categories, each having a minimum FEC requirement:




12.98dB loss

the highest grade, and no FEC is required


16.48dB loss

the middle grade, and BASE-R or RS FEC is required


22.48dB loss

the lowest grade, and RS FEC is required


Can customers use third party copper cables?

JTOPTICS does not restrict the use of third party passive copper cables – however, all copper cables are required to comply with the associated IEEE specifications, as well as SFF-8636 management interface / EEPROM specifications to allow them to be correctly identified and recognized by an JTOPTICS switch / router. Interfaces with cables that are not recognized correctly will be disabled.


How do you change 100G QSFP ports to support QSFP+ 40GbE transceivers?

Configure the desired speed as 40G:

(config)# interface Ethernet1/1

(config-if-Et1/1)# speed forced 40gfull


How do you change 100G QSFP ports to support 4x10GbE mode using a QSFP+ transceiver?

Configure the desired speed as 10G:

(config)# interface Ethernet1/1 - 4 (config-if-Et1/1-4)# speed forced 10000full


How do you change 100G QSFP ports from 100GbE mode to 4x25G mode?

Configure the desired speed as 25G:

(config)# interface Ethernet1/1 - 4 (config-if-Et1/1-4)# speed forced 25gfull


How do you change 100G QSFP ports back to the default mode?

Configure the port to default mode:

(config)# interface Ethernet1/1-4 (config-if-Et1/1)# no speed


How do you enable FEC to achieve 40km distance with QSFP-100G-ERL4?

Enable FEC for maximum 40km reach

(config-if-Et3/4/1)#error-correction encoding reed-solomon

Disable FEC for IEEE compliance (maximum 30km reach)

(config-if-Et3/4/1)# no error-correction encoding


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