China Slaps Anti Dumping Tariffs on US Optical Fiber After First Anti Circumvention Probe

China widens fiber trade curbs after probe finds duty evasion

China has imposed steep anti dumping tariffs on select US optical fiber products after investigators concluded that American exporters changed shipping and labeling practices to sidestep existing duties. The Ministry of Commerce said the new rates, ranging from 33.3 percent to 78.2 percent, take effect immediately and will run through April 21, 2028. The decision follows a six month anti circumvention inquiry that began in March at the request of domestic producers, marking China’s first case of this kind.

The ruling singles out several well known US suppliers. OFS Fitel faces a 33.3 percent rate, Corning is set at 37.9 percent, and Draka Communications Americas will be charged 78.2 percent. Other US exporters of the covered products will also be subject to the 78.2 percent rate. The Ministry said companies altered trade patterns without commercial justification, an approach that undermined previously imposed anti dumping penalties.

Officials said the measures apply to certain cutoff shifted single mode optical fiber, a niche but important class known in the industry as G.654.C fiber. The product is tailored for long distance networks and undersea cables, where lower signal loss across vast spans is essential. Chinese authorities allege that US shipments of this fiber were used to replace another fiber type already covered by existing duties, but with similar functions and closely related technical characteristics.

The announcement arrived within hours of the US Treasury’s move to sanction a Guangzhou based chemical company and two individuals in a fentanyl related action. Beijing did not link the measures to those sanctions. Chinese media and official notices framed the decision as a legal step to preserve the effectiveness of trade remedies already in place, not as retaliation. Still, the timing highlights a tense period in US China economic relations as both sides harden trade tools in advanced manufacturing and technology supply chains.

What product is targeted and why it matters

The new tariffs focus on a specific category of single mode optical fiber, sometimes labeled G.654.C. Single mode fiber carries light signals through a tiny core so that information can travel with very low signal loss over long distances. This is the backbone used in national internet trunks, cross border links, and subsea systems that connect continents. By comparison, multi mode fiber uses a larger core, is cheaper over short distances, and is common inside buildings and campus networks.

How single mode fiber works

In any fiber link, two engineering challenges govern performance at scale. The first is attenuation, or how quickly the light signal fades as it travels. The second is dispersion, or how a pulse of light spreads out over distance. Excessive dispersion blurs the signal and reduces the maximum data rate without expensive compensation equipment. Single mode fiber reduces both problems compared with multi mode, which is why telecom carriers use it for city to city, national, and subsea backbones.

Why G.654.C is different

G.654.C fiber is engineered for very low attenuation and stable performance at the wavelengths used in long distance transmission. That profile makes it attractive for undersea routes and remote terrestrial spans where repeaters or amplifiers are expensive to install and maintain. Industry reporting from Caixin noted that Chinese authorities identified this product as the substitute that US exporters shipped in place of fiber that already faced anti dumping duties. In simple terms, it is a high end single mode fiber with characteristics optimized for long reach networks, which gives it a distinct role in global connectivity.

China is a major consumer and producer of optical fiber. Telecom operators continue to expand national backbones, data center interconnections, and international links, even as 5G and cloud services push more traffic onto fiber. Any tariff change in this niche can influence procurement costs and supplier choices for projects that require very low loss spans.

Inside China’s first anti circumvention inquiry

Anti circumvention cases examine whether exporters changed their practices to avoid an existing trade remedy, such as a tariff on a closely related product. China’s Ministry of Commerce opened this investigation on March 4 after a domestic firm applied for relief. State linked media reported that the applicant argued imports under the tariff covered codes had fallen, while shipments under similar but uncovered codes had surged. That pattern, the applicant said, damaged Chinese industry and weakened the original duties.

Authorities conducted questionnaires, hearings, and on site verification, a process that MOFCOM says aligns with Chinese law and World Trade Organization practices. The outcome extends the scope of China’s earlier anti dumping order beyond dispersion unshifted single mode fiber to include certain cutoff shifted single mode fiber. To ensure consistent declaration, China’s customs authority instructed importers to use product code 90011000.01 for the affected fiber.

A spokesperson for the Ministry’s trade remedy bureau framed the outcome as a necessary step to preserve the effect of earlier measures and to support domestic producers. The official described the exporters’ tactics and why they were judged to undermine the original order.

MOFCOM found that US fiber optic manufacturers and exporters altered trade patterns to ship certain cutoff shifted single mode optical fiber to China without commercial justification. This behavior undermines existing anti dumping measures and constitutes circumvention of China’s anti dumping measures on related US optical fiber products.

Scholars inside China also linked the move to standard global practice. Bao Jianyun of Renmin University told the Global Times that first time anti circumvention tools would make enforcement more effective and strengthen protection of local industry. Bao said the decision signals Beijing’s resolve to uphold a fair competitive environment for Chinese companies.

Who gets hit and by how much

According to official notices and reports from SCMP, Bloomberg, Caixin, and state media, the new duty rates apply as follows:

• OFS Fitel: 33.3 percent
• Corning: 37.9 percent
• Draka Communications Americas: 78.2 percent
• All other US exporters covered by the decision: 78.2 percent

The measures apply through April 21, 2028. Importers of the covered products typically must pay cash deposits or duties at customs equal to the specified percentage of the declared value. China’s commerce ministry has imposed anti dumping duties on another category of US and European single mode fiber since 2011, and it extended those duties for five more years in April 2023. Seeking Alpha and other outlets note that rates on some fiber imports into China have reached levels similar to the new order in past cases.

Company impacts will vary by exposure to China’s market and by each supplier’s production footprint outside the United States. Corning, a major fiber and cable producer, faces a mid range rate under the ruling. OFS Fitel, a US based maker of fiber and cable, receives the lowest rate. Draka Communications Americas, part of a global group with facilities across regions, is assigned the highest rate for the products covered by the investigation. Firms not named in the findings face the 78.2 percent rate unless they secure a different treatment through later administrative processes.

For Chinese buyers, the decision is likely to push orders toward domestic producers and non US sources for the covered fiber category. China’s leading fiber makers, including YOFC and FiberHome affiliates, have large capacity and a strong presence in national projects. The tariff shift may change bid dynamics in long distance network tenders and international cable routes that link through Chinese landing stations.

Timing and the broader US China trade climate

The tariff announcement followed shortly after the US Treasury sanctioned Guangzhou Tengyue Chemical and two individuals for alleged roles in illicit opioid supply chains. Multiple outlets, including SCMP and Anadolu Agency, noted the proximity in timing. Chinese authorities presented the fiber decision as the result of a legal process that began months earlier. The parallel actions highlight how fast moving events in export controls, sanctions, and trade remedies now overlap in the economic relationship.

US China trade tensions have intensified in advanced industries such as semiconductors, electric vehicles, batteries, and telecommunications. Washington has tightened export controls on high end chips and related equipment, and has maintained or raised tariffs on a wide range of Chinese goods. Beijing has responded with its own trade remedy actions and a growing toolkit that includes export licensing, cybersecurity reviews, and anti dumping probes. Each side tends to cite domestic law and WTO rules to justify measures, while close observers track the cross currents for signs of escalation.

Chinese legal experts argue the fiber case follows widely used frameworks. Shi Xiaoli, who directs the WTO Law Research Center at China University of Political Science and Law, described anti circumvention as a recognized mechanism for maintaining the effectiveness of trade remedies.

The investigation aligns with Chinese laws and WTO practices. If circumvention is confirmed, authorities can expand the scope of taxation to close loopholes and ensure that earlier measures remain effective.

What it means for telecom builders and data centers

For carriers, cloud platforms, and undersea cable consortia, the immediate question is sourcing. The covered fiber is used in the longest spans. Domestic Chinese fiber makers can produce similar grades at scale. This reduces the risk of project delays, but procurement teams may still face higher prices in the short term because any shift in supply comes with negotiation costs and limited competition for the targeted grade.

For US suppliers, the ruling narrows access to a major market for this specific product. Companies may focus on serving projects outside China or work through overseas production sites if those sites do not trigger the country of origin rules tied to the order. Multi year telecom projects often rely on supplier frameworks that span multiple regions, so some orders can be redirected. That approach, however, depends on the exact scope of the measure and how customs authorities enforce the product definition at ports.

For project owners, total cost of ownership remains the core concern. Fiber itself is a portion of overall spend, which also includes cable manufacturing, installation, rights of way, amplifiers, repeaters, and network equipment. Where the upgraded fiber grade is essential for performance, buyers are likely to prioritize continuity and specification compliance rather than seek a downgrade to avoid duties.

How anti dumping and anti circumvention work

Anti dumping cases allege that foreign exporters sell products at unfairly low prices that injure domestic producers. If a government confirms dumping and injury, it sets duty rates for named companies and a rate for all others. These cases often include detailed cost analysis and comparisons of export prices to constructed normal values. Once duties are in place, companies sometimes alter products or shipping arrangements to avoid the scope. This is where anti circumvention comes in.

Anti circumvention investigations examine whether changes in trade patterns, product characteristics, or routing through third countries should be treated as attempts to avoid the original order. If confirmed, authorities can expand the scope to cover the newly used product category, apply duties retroactively in some jurisdictions, or tighten customs classification rules. Many WTO members use these tools. China’s decision to pursue its first anti circumvention case indicates that it intends to police the boundaries of earlier anti dumping findings more closely.

China has policed US and European single mode fiber since 2011 under a separate anti dumping order on dispersion unshifted single mode fiber. In April 2023, Beijing extended that order for five more years. The new ruling adds certain cutoff shifted single mode fiber to the coverage. That linkage explains why investigators focused on whether US exporters switched to a technically similar, interchangeable product to maintain sales while avoiding the scope of the earlier decision.

Key Points

• China imposed new anti dumping duties on certain US single mode optical fiber ranging from 33.3 percent to 78.2 percent, effective immediately through April 21, 2028.
• OFS Fitel faces 33.3 percent, Corning 37.9 percent, and Draka Communications Americas 78.2 percent, with other US exporters also at 78.2 percent.
• The ruling covers certain cutoff shifted single mode fiber, often referred to as G.654.C, used in long distance and undersea networks.
• MOFCOM concluded that US exporters altered trade patterns and product declarations to circumvent existing fiber duties imposed since 2011 and extended in 2023.
• The investigation, launched March 4 at the request of a Chinese firm, is China’s first anti circumvention case and included questionnaires, hearings, and on site checks.
• Customs instructed importers to declare the covered fiber under product code 90011000.01.
• The announcement came hours after US sanctions on a Guangzhou chemical firm in a fentanyl related action, underscoring a tense trade climate.
• Chinese officials say the decision follows domestic law and WTO practices and aims to protect the effectiveness of existing trade remedies and domestic industry.