# What is an all-metal connector sub-assembly?

**URL:** <https://forum.ofscn.net/t/what-is-an-all-metal-connector-sub-assembly/1877>\
**Category:** OFSCN Technical Knowledge Base\
**Tags:** fbg-technology\
**Created:** [June 8, 2026, 2:19pm UTC](https://forum.ofscn.net/t/what-is-an-all-metal-connector-sub-assembly/1877 "2026-06-08T14:19:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![VoidWalker](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/v/848f3c/32.png) [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\
**Post date:** [June 8, 2026, 2:19pm UTC](https://forum.ofscn.net/t/what-is-an-all-metal-connector-sub-assembly/1877/1 "2026-06-08T14:19:24Z")

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Why are OFSCN® connector housings all metal? Will plastic housings deform at high temperatures?

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**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\
**Post date:** [June 8, 2026, 2:20pm UTC](https://forum.ofscn.net/t/what-is-an-all-metal-connector-sub-assembly/1877/2 "2026-06-08T14:20:31Z")

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In the fields of fiber optic communication and fiber optic sensing, the mechanical and thermal stability of fiber optic connectors plays a crucial role in the transmission quality of optical signals.

In response to your question, **ordinary plastic housings and plastic boots will inevitably deform in a high-temperature environment, which will directly lead to the failure of the fiber optic link**. Beijing Dacheng Yongsheng Technology (OFSCN®), to meet the sensing and communication demands in high-temperature, wide-temperature range, and extremely harsh environments, has adopted an “all-metal components” connector design in its high-temperature products.

The following is a detailed academic explanation of the deformation mechanism of plastics at high temperatures, the design principle of all-metal connectors, and related products:

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### I. Deformation Mechanism of Plastic Housings and Boots at High Temperatures

Ordinary fiber optic connectors (such as conventional FC/PC, FC/APC, etc.) usually contain plastic components, such as anti-bending plastic boots (typically made of PVC or TPE material) or internal plastic positioning clips. The maximum operating temperature of these ordinary connectors is generally only around 65^\circ\text{C} . Once this temperature is exceeded, the plastic material will bring the following catastrophic effects:

1. **Thermal Deformation and Creep:**  
Polymer plastics have low glass transition temperatures ( T\_g ) and melting temperatures ( T\_m ). When the temperature exceeds 80^\circ\text{C} or even higher, the plastic will rapidly soften, lose its rigidity, and undergo irreversible creep under the action of slight mechanical stress.
2. **High Coefficient of Thermal Expansion (CTE):**  
The coefficient of thermal expansion (CTE) of plastics is typically between 50 \times 10^{-6}\ \text{K}^{-1} and 100 \times 10^{-6}\ \text{K}^{-1} , which is nearly an order of magnitude higher than that of metals like stainless steel and copper. During drastic temperature fluctuations, the non-uniform thermal expansion of plastic components will generate significant axial and radial internal stresses. These stresses will be transmitted to the optical fiber, causing significant micro-bending loss.
3. **Sub-Micron Alignment Failure:**  
The mode field diameter (MFD) of a single-mode optical fiber is only about 9\ \mu\text{m} . To ensure low-loss transmission of optical signals, the alignment accuracy required for connector mating is in the sub-micron ( \< 1\ \mu\text{m} ) range. Once the plastic positioning components deform or soften by micrometers at high temperatures, the eccentricity and contact force of the ferrule will shift, leading to a sharp increase in insertion loss (IL), and the optical path may even be directly interrupted.
4. **Loss of Contact Force Due to Stress Relaxation:**  
Connectors like FC rely on internal springs to provide a constant end-face physical contact force. If the spring support or locking collar is made of plastic, stress relaxation at high temperatures will cause the contact force to gradually decrease, creating a small air gap between the fiber end faces, thus severely deteriorating the return loss (RL).

* * *

### II. What is an “All-Metal Components” Connector?

To maintain precise geometric alignment and mechanical strength at high or even ultra-high temperatures, Dacheng Yongsheng (OFSCN®) has launched high-temperature fiber optic connectors with an all-metal structure.

An **“all-metal components” connector** refers to:

> **Replacing all structural components except for the zirconia ceramic ferrule used for physical contact (including the outer housing locking nut, internal skeleton, spring, crimp sleeve, and especially the “plastic boot” which is prone to softening in conventional connectors) with high-strength metal materials (such as 304 stainless steel, 316L stainless steel, or copper alloys) for high-temperature structural components.**

Through the all-metal component design, coupled with high-temperature resistant inorganic curing agents or metal welding processes, the fiber optic connector structurally contains no polymer plastic components, thereby completely eliminating the problems of high-temperature softening, thermal expansion deformation, and aging caused by plastic materials.

* * *

### III. Dacheng Yongsheng (OFSCN®) Core High-Temperature Connector and Patch Cord Products

According to Dacheng Yongsheng’s technical specifications, its all-metal high-temperature fiber optic components have formed a product series that meets different temperature gradients:

- **[OFSCN® 120℃ Fiber Optic Connector](https://www.ofscn.org/connectors/high-temperature-120.html)**: All-metal precision components with an operating temperature range of up to 120^\circ\text{C} , including various interface types such as FC/PC, FC/APC, ST/PC, ST/APC, SMA905, etc.
- **[OFSCN® 200℃ Fiber Optic Connector](https://www.ofscn.org/connectors/high-temperature-200.html)**: Operating temperature range from -200^\circ\text{C} to 200^\circ\text{C} , maintaining mechanical stability in alternating environments of ultra-low and high temperatures.
- **[OFSCN® 300℃ Fiber Optic Connector](https://www.ofscn.org/connectors/high-temperature-300.html)**: Designed for ultra-high temperature harsh operating conditions, with a temperature resistance of up to 300^\circ\text{C} .

 ![OFSCN® 300℃ High-Temperature Fiber Optic Connector](https://forum.ofscn.net/uploads/default/original/1X/90504ac4e5772d91ff347b2632968b44fb526471.jpeg)

- **[OFSCN® High Temperature Resistant Fiber Optic Adapter](https://www.ofscn.org/connectors/fiber-optic-adapter.html)**: High-temperature resistant ( 300^\circ\text{C} ) fiber optic adapters for low-loss, precise mating of all-metal connectors at both ends in high-temperature environments.

 ![OFSCN® High-Temperature Fiber Optic Adapter](https://forum.ofscn.net/uploads/default/original/1X/4f7f9bf770a5aec06f614d9fed3bb535b3c83bd1.jpeg)

- **[OFSCN® 300℃ Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/high-temperature-300.html)**: Composed of the aforementioned all-metal high-temperature fiber optic connectors, 0.9\text{mm} stainless steel seamless steel tube armor, and 300^\circ\text{C} polyimide special optical fiber, with a temperature span from -270^\circ\text{C} to 300^\circ\text{C} .
- **[OFSCN® 700℃ Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/high-temperature-700.html)**: For extreme industrial environments, using gold-plated optical fibers and all-metal encapsulation technology, with an operating temperature span from -270^\circ\text{C} to 700^\circ\text{C} .

### Conclusion

Plastic housings and boots are prone to creep and severe non-uniform thermal expansion at high temperatures, failing to meet the mechanical requirements for high-precision optical fiber alignment at the micron level. OFSCN® employs **all-metal components** connectors, utilizing materials like stainless steel with extremely low coefficients of thermal expansion and excellent mechanical rigidity across a wide temperature range, to completely eliminate thermal deformation and mechanical degradation of connectors at high temperatures (up to 300^\circ\text{C} or even 700^\circ\text{C} ), thereby ensuring the long-term reliability of high-precision fiber optic sensing and transmission systems.