What Coset does

Coset (Coset, Inc.) is a South Korean optical components manufacturer founded in 1999 and headquartered in Gwangju. The company designs and manufactures optical sub-assemblies — TOSA (Transmitter Optical Sub-Assembly), ROSA (Receiver Optical Sub-Assembly), and BOSA (Bidirectional Optical Sub-Assembly) — as well as pump lasers and SLEDs (Superluminescent Light Emitting Diodes) used in 100G and 400G optical transceivers. Its core technology centers on proprietary packaging processes, in-house lensed fiber fabrication, and Telcordia 468-CORE reliability qualification, with manufacturing operations in Daejeon and a second Gwangju site, plus a joint venture in India (CS Laser LLP). The company went public on Korea's KONEX market in 2013.

Name

Coset

Legal name

Coset, Inc.

Website

https://coset.com

Company type

Public

Founded year

1999

Operating status

Operating

Headcount range

11–50 employees

Short description

Coset is a South Korean optical components manufacturer specializing in TOSA, ROSA, and BOSA packaging for 100G/400G transceivers, pump lasers, and SLEDs, supplying B2B customers across the optical networking industry.

Ownership category

akta.pro rank

Product category

Optical Components / Photonic Sub-Assemblies

NAICS

Radio and Television Broadcasting and Wireless Communications Equipment Manufacturing (334220), Semiconductor and Related Device Manufacturing (334413)

SIC

Radio & Tv Broadcasting & Communications Equipment (3663), Semiconductors & Related Devices (3674)

akta.pro primary industry

Optical Transceivers (SFP/SFP+/SFP28/QSFP/QSFP-DD/OSFP) (HDAFAEAE)

akta.pro secondary industries

Optoelectronic Receivers & Transceivers (Photodetectors/Optical Modules) (HDAHALAM), Advanced Packaging (2.5D/3D-IC, Fan-Out WLP, Chiplets) (HDAHADAB)

Keywords

• Optical sub-assemblies
• TOSA ROSA BOSA
• Optical transceivers
• Pump lasers
• Photonic packaging

Headquarters

HQ city

Gwangju

HQ country

South Korea

HQ region

Asia

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Technology or R&D, Infrastructure, Marketing or Sales

Revenue model

1. Optical Components and Sub-Assemblies Sales: Coset generates revenue through the manufacture and sale of optical transmission parts including TOSA, ROSA, BOSA products, pump lasers, SLEDs, and 100G/400G transceivers to optical system manufacturers and network providers. The company operates on a project-based B2B model working directly with customers from design through volume production.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels2 records

Core offering

Coset manufactures and sells optical transmission parts including TOSA (Transmitter Optical Sub-Assemblies), ROSA (Receiver Optical Sub-Assemblies), BOSA (Bidirectional Optical Sub-Assemblies), 980nm pump lasers, SLEDs, and 100G/400G QSFP28 transceivers. The company specializes in optical sub-assembly packaging for semiconductor diode chips, supporting high-speed 100G and 400G transmission applications for data centers, 5G, and telecom networks. Products are sold B2B to optical system manufacturers and network providers under custom/ODM engagements.

Product overview

Coset is a 400G Ready optical transmission parts manufacturer offering a portfolio of Optical Sub-Assemblies (TOSA/ROSA/BOSA) and QSFP28 transceivers. The product line includes 400G CWDM PAM4 TOSA and ROSA FR4 components operating at 4 x 53GBaud with center wavelengths of 1271, 1291, 1311, and 1331 nm. The 100G product family comprises LAN-WDM and CWDM variants in both TOSA and ROSA form factors (LR4 for 10km, ER4-Lite for 30-40km), plus complete QSFP28 transceivers. Additional offerings include 25Gbps LAN-WDM EML TOSA and BOSA components for 5G wireless and SFP28 ER applications. The company provides both commercial temperature (CT) and industrial temperature (IT) grades across its product range.

Differentiator

Problem solved

Functional benefit

Products and services

• 400G CWDM PAM4 TOSA FR4 400Gbps CWDM PAM4 Transmitter Optical Sub-Assembly for FR4 applications, operating at 4 x 53GBaud with center wavelengths of 1271, 1291, 1311, and 1331 nm. Designed for optical system manufacturers building next-generation 400G transceivers.
• 400G CWDM PAM4 ROSA FR4 400Gbps CWDM PAM4 Receiver Optical Sub-Assembly for FR4 applications, featuring integrated Quad PIN-PD and Linear TIA Arrays with I2C Protocol Interface. Used by optical system manufacturers building 400G receivers.
• 100G LAN-WDM TOSA LR4 100Gbps LAN-WDM Transmitter Optical Sub-Assembly for LR4 applications, supporting 4-channel operation at wavelengths 1295.56, 1300.05, 1304.58, and 1309.14 nm with integrated quad LD driver IC and DFB-LDs. For 100G transceivers up to 10km.
• 100G LAN-WDM ROSA LR4 100Gbps LAN-WDM Receiver Optical Sub-Assembly for LR4 applications, compatible with QSFP28 transceivers up to 10km with integrated quad PIN-PD and TIA arrays.
• 100G LAN-WDM TOSA ER4-Lite 100Gbps LAN-WDM Transmitter Optical Sub-Assembly for ER4-Lite applications, compatible with CFP4/QSFP28 transceivers up to 30km with integrated EMLs and Monitor PDs.
• 100G LAN-WDM ROSA ER4-Lite 100Gbps LAN-WDM Receiver Optical Sub-Assembly for ER4-Lite applications, featuring quad InGaAs/InP APDs and integrated TIA array. For 100G transmission up to 30-40km.
• 25 Gbps LAN-WDM EML TOSA 25Gbps LAN-WDM Transmitter Optical Sub-Assembly with EA Modulator Integrated DFB-LD, designed for SFP28 ER transceivers up to 30km reach. Suited for 5G wireless and access network applications.
• 25 Gbps LAN-WDM EML/APD BOSA 25Gbps LAN-WDM Bidirectional Optical Sub-Assembly featuring EA Modulator Integrated DFB-LD and InGaAs/InP APD with integrated TIA, compatible with SFP28 transceivers up to 30km. Combines transmit and receive functions in a single package.
• 100G QSFP28 LR4 Transceiver 4 x 25Gbps LAN-WDM QSFP28 transceiver for 100GBASE-LR4 Ethernet, supporting up to 10km transmission distance with dual rate operation. Complete pluggable transceiver for optical network and data center deployments.
• 100G QSFP28 ER4-Lite (CT/IT) Transceiver 4 x 25Gbps LAN-WDM QSFP28 transceiver for 100GBASE-ER4 Lite Ethernet, supporting up to 30km or 40km with FEC, available in commercial and industrial temperature grades.
• 100G QSFP28 FR4 Transceiver 4 x 25Gbps CWDM QSFP28 transceiver for 100GBASE-CWDM4 Ethernet, supporting up to 2km transmission distance with I2C management interface. Complete pluggable transceiver for data center interconnects.

Quantifiable outcome

• Zero defect rate target maintained consistently
• +1 more outcomes

Named customers5 records

Segments3 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Six partnerships are on record, tiered core and major.

• 3SP TechnologiescoreStrategic or Co-development Partner · 1 January 20083SP Technologies made a strategic investment in Coset in 2008 which enabled pump laser mass production. This partnership has continued as Coset manufactures optical products for 3SP Technologies as one of their key industry partners.
• O Net TechnologiescoreStrategic or Co-development PartnerCoset has partnerships and manufactures optical components for O Net Technologies, a major player in optical network solutions.
• FujitsucoreTechnology or IntegrationCoset supplies optical transmission parts to Fujitsu, a leading technology company, as part of their customer base of industry leaders.
• ThorLabsmajorTechnology or IntegrationCoset manufactures optical components for ThorLabs, a photonics industry leader, as part of their customer partnerships.
• LumicsmajorStrategic or Co-development PartnerCoset partners with Lumics for the manufacture of optical products, maintaining their position in the optical communications supply chain.
• CS Laser LLPmajorOthersJoint venture in India (Gandhinagar, Gujarat) for high power laser productions. This partnership extends Coset's manufacturing capabilities internationally.

Scale indicators6 records

Recent moves9 records

Expansion highlights5 records

Direct peers

• Hisense Broadband: Hisense Broadband is a Chinese optical transceiver and OSA manufacturer producing 100G/400G components comparable to Coset's product portfolio. Both compete in CWDM/LAN-WDM TOSA/ROSA for telecom and data center applications.
• Accelink Technologies: Accelink is a Chinese optical component manufacturer producing TOSAs, ROSAs, and transceivers for telecom and data center markets. Directly comparable to Coset in optical sub-assembly manufacturing scope and customer segments.
• Innolight: Innolight is a leading Chinese manufacturer of high-speed optical transceivers (100G/400G/800G), directly competing with Coset's QSFP28 product line and TOSA/ROSA components in data center and telecom markets.
• Source Photonics: Source Photonics manufactures optical transceivers and components for data center and telecom, including 100G/400G QSFP modules. Overlaps directly with Coset's product portfolio in TOSA/ROSA and QSFP28 categories.
• O-Net Technologies: O-Net Technologies is a Hong Kong/Chinese optical component manufacturer producing transceivers, OSA, and active optical components. Both O-Net and Coset serve optical network providers and system manufacturers with comparable high-speed products.

Broad incumbents

• Coherent (formerly II-VI): Coherent is a large US-based photonics incumbent producing lasers, optical components, and materials. Its broad portfolio includes TOSA/ROSA and pump laser products that compete with Coset's specialist OSA packaging offering.
• Broadcom: Broadcom is a major incumbent in optical networking and semiconductors, including high-speed optical components for data centers and telecom. While primarily a chip-level player, its optical portfolio overlaps Coset's OSA/transceiver space.
• Lumentum: Lumentum is a major US-based incumbent in optical components, lasers, and photonic products serving telecom, data center, and 3D sensing markets. While broader in scope than Coset, Lumentum's OSA and laser portfolio overlaps Coset's specialty packaging niche.
• Mitsubishi Electric: Mitsubishi Electric is a Japanese incumbent producing optical devices including laser diodes and sub-assemblies for telecom. Directly comparable to Coset in pump laser and optical sub-assembly manufacturing.

Emerging players

• Luxshare Precision: Luxshare is an emerging player expanding into optical communications including high-speed interconnect products. While broader in electronics manufacturing, its optical segment is increasingly competing with Coset in transceiver/OSA space.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat5 records

Key risks5 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/coset-inc

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles8 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Coset