# Linear Pluggable Optics
**Linear Pluggable Optics** (LPO) is an optical transceiver architecture for data center links in which the pluggable module contains no digital signal processor (DSP) or retimer; the module's electronics operate linearly, and the switch or network interface card ASIC performs the equalization and timing recovery for the entire electrical and optical channel.[1](https://www.lpo-msa.org/home/faqs.html) Removing the DSP lowers module power, cost, and latency, which is why LPO has been aimed primarily at short-reach 400G, 800G, and 1.6T links inside AI and machine learning clusters.[1](https://www.lpo-msa.org/home/faqs.html) • [2](https://eoptolink.com/news/341-eoptolink-launches-innovative-800g-linear-drive-pluggable-optics-during-ofc-2023)
| Key fact | Detail |
|---|---|
| Defining feature | No DSP or clock-and-data-retimer inside the module; the end-to-end signal path is linear and the host ASIC's SerDes handles equalization[1](https://www.lpo-msa.org/home/faqs.html) |
| Power at 200G per lane | Retimed DSP modules 23–25 W; transmit-retimed LRO about 16 W; LPO targeting about 10 W[3](https://blog.semtech.com/200g-lpo-power-reach-and-loss-real-numbers) |
| System-level saving | Arista reports LPO support on its 7060XE7 1.6T switches reduces interconnect power consumption by approximately 60%[4](https://www.arista.com/en/company/news/press-release/24102-pr-20260609) |
| Standardization | The LPO MSA, a group of 50 networking, semiconductor, and optics companies, released its 100 Gb/s per lane single-mode specification in March 2025, covering 100G through 800G Ethernet[5](https://www.lpo-msa.org/news/lpo-msa-announces-release-of-specification-for-linear-pluggable-optica) |
| First 800G products | Eoptolink launched 800G LPO modules at OFC 2023 in March 2023[2](https://eoptolink.com/news/341-eoptolink-launches-innovative-800g-linear-drive-pluggable-optics-during-ofc-2023) |
| Main trade-off | Link conformance depends on the specific host-module-host combination, making multi-vendor interoperation harder than with retimed modules[6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo) |
## How it works
In a conventional retimed pluggable module, a DSP sits between the host ASIC and the optics. The host SerDes talks to the module DSP over a defined electrical interface, and the DSP regenerates and digitally compensates the signal before driving the laser or recovering the receiver output. This regeneration defines clean [demarcation points](https://www.edgepedia.org/demarcation-point) and makes modules broadly interchangeable, but the DSP consumes a large share of the module's power and adds latency.[7](https://www.oiforum.com/wp-content/uploads/OIF_PLL_Demo_Eoptolink_ECOC2023.pdf) • [6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo)
LPO removes that regeneration step. The module keeps only linear analog components, drivers and transimpedance amplifiers (TIAs) with high linearity, and the link from host ASIC to host ASIC becomes a single continuous channel. Modern switch and NIC ASICs carry capable transmitters and receivers that are normally underused when a retimed module sits in between; with LPO, those SerDes equalize the whole electrical and optical path themselves.[1](https://www.lpo-msa.org/home/faqs.html) The approach was enabled by SerDes advances in the host ASIC, which added the equalization reach needed to cover the entire link without an intermediate retimer.[7](https://www.oiforum.com/wp-content/uploads/OIF_PLL_Demo_Eoptolink_ECOC2023.pdf)
The consequence is tighter co-design. Because no signal regeneration occurs in the module, the host SerDes, the module, and the channel between them must be designed within a shared loss and noise budget, and link conformance depends on the specific host-module-host combination rather than on standardized module-only test points.[6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo) In one published 800G linear direct-drive design, the measured TX/RX host loss was 7 dB, and the authors recommended stricter host signal-integrity metrics than for retimed systems.[8](https://www.signalintegrityjournal.com/articles/3649-800g-linear-direct-drive-network-system-design-and-implementation)
## Related architectures
LPO sits among several options for short-reach data center optics, distinguished by where retiming happens:
- **Fully retimed pluggable modules** carry a DSP that regenerates the signal in both directions. They offer the most standardized, interchangeable link at the cost of the highest power; at the 1.6T generation a full-DSP module runs on the order of 20 W, with the DSP roughly half of the module's dissipation.[6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo)
- **LRO (Linear Receive Optics)**, also called RTLR (Retimed Transmit, Linear Receive), retimes only the transmit side and keeps the receive path linear. The transmit DSP shapes and retimes the signal while a linear TIA feeds the host directly on the receive side. It recovers part of LPO's power saving while relaxing the co-design constraints.[9](https://www.topnetsystem.com/lpo-lro-linear-pluggable-optics.html) • [10](https://www.fiberwdm.com/lpo-lro-tro-optical-modules-the-evolution-of-low-power-interconnect-architectures-for-ai-data-centers_n125) The OIF approved the RTLR project in January 2024[11](https://online.flippingbook.com/view/940580562/19/) and published the EEI-112G-RTLR implementation agreement in November 2025.[12](https://troy-technical.com/photonics-term-npo-lpo/)
- **Co-packaged optics (CPO)** moves the optical engine onto the switch substrate next to the ASIC, shortening the electrical traces further. CPO achieves the lowest power but replaces the hot-swappable pluggable model, so a failed engine is harder to service; LPO keeps the front-panel pluggable form factor while approaching CPO's efficiency.[6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo) • [13](https://www.exponentialindustry.com/blog/2026-09-22-linear-pluggable-optics-lpo-ai-data-center-buildout/)
At 200G per lane, industry observers have expected LRO to be the more practical choice for 1.6T modules, since initial 200G/lane linear solutions required more than 30 W.[14](https://eps.ieee.org/images/files/Photonics_TC_Article_-Linear_Pluggable_Optics_-_An_Overview.pdf)
## Power and cost
Power is the primary commercial driver. For 200G-per-lane links, Semtech's published figures put retimed DSP modules at 23 to 25 W each (expected to fall to about 20 W with next-generation DSPs), transmit-retimed LRO at about 16 W, and LPO at a target of about 10 W, well under half the retimed figure.[3](https://blog.semtech.com/200g-lpo-power-reach-and-loss-real-numbers) At switch scale, the same source estimates that converting a 512-port switch built on the Tomahawk-6 generation from retimed to LPO modules saves approximately 500 W at the module level, rising to nearly 1 kW once cooling is included.[3](https://blog.semtech.com/200g-lpo-power-reach-and-loss-real-numbers) Arista's 1.6T 7060XE7 Series cites an approximately 60% reduction in interconnect power consumption from LPO support, lowering total cost of ownership.[4](https://www.arista.com/en/company/news/press-release/24102-pr-20260609)
Individual products show how low the module power can go. Adtran's LiteWave800, an OSFP 800G-DR8 LPO module with 500 m reach built on 100-gigabit single-mode VCSEL lasers, consumes less than 1 W.[15](https://gazettabyte.com/adtran-breaks-the-1w-barrier-with-800g-linear-pluggable-optics/)
## Standardization and ecosystem
The **LPO MSA** (Linear Pluggable Optics Multi-Source Agreement) was founded in March 2024 to define the optical and electrical specifications for interoperable LPO products, building on earlier OIF work on CEI-112G-LINEAR-PAM4.[16](https://www.lpo-msa.org/news/lpo-msa-announces-successful-multi-vendor-interoperability) • [1](https://www.lpo-msa.org/home/faqs.html) Its members include Accelink, AMD, Arista, Broadcom, Bytedance, Cisco, Eoptolink, Hisense, Intel, Keysight Technologies, MACOM, MultiLane, NVIDIA, and Semtech.[16](https://www.lpo-msa.org/news/lpo-msa-announces-successful-multi-vendor-interoperability) At ECOC 2024 the group announced successful multi-vendor interoperability testing over 400 Gb/s and 800 Gb/s parallel single-mode links, with results exceeding link-budget requirements.[16](https://www.lpo-msa.org/news/lpo-msa-announces-successful-multi-vendor-interoperability) On March 25, 2025, at OFC, the MSA released its completed 100 Gb/s per lane Linear Pluggable Optics Single-Mode Optical Data Transmission specification, covering 100G, 200G, 400G, and 800G Ethernet parallel single-mode links; MSA co-chair Andreas Bechtolsheim, a networking industry veteran and [Arista Networks](https://www.edgepedia.org/arista-networks) founder, said it allows large data center operators to deploy 800G LPO modules in volume with confidence.[5](https://www.lpo-msa.org/news/lpo-msa-announces-release-of-specification-for-linear-pluggable-optica)
Product availability followed the demonstrations. Eoptolink introduced its 800G LPO family, in OSFP and QSFP-DD800 form factors over multimode (VCSEL) and single-mode (silicon photonics, EML, and thin-film lithium niobate) transmitters, at OFC 2023.[2](https://eoptolink.com/news/341-eoptolink-launches-innovative-800g-linear-drive-pluggable-optics-during-ofc-2023) Cisco released its first commercially available 800G LPO modules for Nexus 9000 series switches and 8000 series routers in February 2026.[17](https://www.datacenterdynamics.com/en/analysis/optical-illusion-is-co-packaged-optics-the-savior-the-data-center-industry-has-been-waiting-for/) Arista's 7060XE7 1.6T switch family, announced in June 2026, lists LPO support across air-cooled and liquid-cooled platforms.[4](https://www.arista.com/en/company/news/press-release/24102-pr-20260609)
## Limitations
The main cost of deleting the DSP is system-level qualification. Because the link has no regeneration point, multi-vendor LPO interoperation is harder at 100G per lane and harder still at 200G, and deployment has concentrated in single-operator environments that qualify host-module-host combinations themselves.[6](https://www.photonica.io/articles/pluggable-lpo-lro-cpo) Linear links also raise testability questions, since the diagnostic visibility that a module DSP provides is reduced; the LPO MSA has published a white paper describing link monitoring built from diagnostics already integrated in components along the signal path.[16](https://www.lpo-msa.org/news/lpo-msa-announces-successful-multi-vendor-interoperability) Reach is shorter than for retimed modules, which is why LPO targets intra-data center links rather than longer-haul applications.[9](https://www.topnetsystem.com/lpo-lro-linear-pluggable-optics.html)
## References
1. [LPO MSA Frequently Asked Questions](https://www.lpo-msa.org/home/faqs.html)
2. [Eoptolink Launches Innovative 800G Linear-drive Pluggable Optics During OFC 2023](https://eoptolink.com/news/341-eoptolink-launches-innovative-800g-linear-drive-pluggable-optics-during-ofc-2023)
3. [200G Linear Pluggable Optics (LPO) Power, Reach and Loss: Real Numbers, Semtech](https://blog.semtech.com/200g-lpo-power-reach-and-loss-real-numbers)
4. [Arista Introduces Next-Generation 1.6Terabit Portfolio for AI Fabrics, Arista Networks](https://www.arista.com/en/company/news/press-release/24102-pr-20260609)
5. [LPO MSA Announces Release of Specification for Linear Pluggable Optical Modules](https://www.lpo-msa.org/news/lpo-msa-announces-release-of-specification-for-linear-pluggable-optica)
6. [LRO vs LPO vs CPO: Power per Bit, Photonica](https://www.photonica.io/articles/pluggable-lpo-lro-cpo)
7. [Linear Drive Pluggable Optics, OIF demonstration document (Eoptolink, ECOC 2023)](https://www.oiforum.com/wp-content/uploads/OIF_PLL_Demo_Eoptolink_ECOC2023.pdf)
8. [800G Linear Direct Drive Network System Design & Implementation, Signal Integrity Journal](https://www.signalintegrityjournal.com/articles/3649-800g-linear-direct-drive-network-system-design-and-implementation)
9. [LPO and LRO Explained: Linear Pluggable Optics for AI, TopNet System](https://www.topnetsystem.com/lpo-lro-linear-pluggable-optics.html)
10. [LPO, LRO/TRO optical modules: The evolution of low-power interconnect architectures for AI data centers, FiberWDM](https://www.fiberwdm.com/lpo-lro-tro-optical-modules-the-evolution-of-low-power-interconnect-architectures-for-ai-data-centers_n125)
11. [ECOC Exhibition 2024 Show Guide, page 19](https://online.flippingbook.com/view/940580562/19/)
12. [NPO and LPO Explained, Troy Technical](https://troy-technical.com/photonics-term-npo-lpo/)
13. [Linear Pluggable Optics (LPO) for AI Data Centers, Exponential Industry](https://www.exponentialindustry.com/blog/2026-09-22-linear-pluggable-optics-lpo-ai-data-center-buildout/)
14. [Linear Pluggable Optics – An Overview, IEEE EPS Photonics TC](https://eps.ieee.org/images/files/Photonics_TC_Article_-Linear_Pluggable_Optics_-_An_Overview.pdf)
15. [Adtran breaks the 1W barrier with 800G linear pluggable optics, Gazettabyte](https://gazettabyte.com/adtran-breaks-the-1w-barrier-with-800g-linear-pluggable-optics/)
16. [LPO MSA Announces Successful Multi-Vendor Interoperability](https://www.lpo-msa.org/news/lpo-msa-announces-successful-multi-vendor-interoperability)
17. [Optical illusion: Is co-packaged optics the savior the data center industry has been waiting for?, Data Center Dynamics](https://www.datacenterdynamics.com/en/analysis/optical-illusion-is-co-packaged-optics-the-savior-the-data-center-industry-has-been-waiting-for/)
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*Topic: Encyclopedia › Technology and the built world › Computing and digital systems › Networks and security › Networking fundamentals and architecture › Network hardware and vendors › Pluggable transceivers and optical modules*
*Initially written Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license