F700 – D38999 Series III

Designed for demanding civil and military electronic equipment interfaces, the D38999 Series III expanded beam fibre optic connectors offer high-performance, flexibility and cost effectiveness. These connectors use the same inserts as our F BEAMTM products.

Featuring the MIL-DTL-38999 Series III tri-start thread and a one-turn self-locking anti-vibration coupling mechanism, these connectors excel in armoured vehicles, aircraft, and naval systems.

Connectors are available as plugs or receptacles with straight or 90o back shell options. Receptacles are available with jam-nut or square-flange mounting and strain relief. These connectors are easy to clean, resistant to environmental contamination and less susceptible to variations in temperature and humidity.

Ridgemount D38999 connectors are available with either singlemode and multimode fibre.


  • Civil aircraft communications equipment interfaces
  • Military aircraft, and naval electronics equipment
  • Petrochemical, mining and outside broadcast systems
  • Armoured personnel carriers and tanks

F700 Series

D38999 Expanded Beam Connector

Specification Performance

Optical Performance

- subject to termination method and fibre grade

Insertion Loss [Max]

IEC 61300-3-4

Mmode ≤1.5dB / Smode ≤2.0dB

Insertion Loss [Typical]

IEC 61300-3-4

Mmode ≤0.8dB / Smode ≤1.0dB

Return Loss

IEC 61300-3-6 [mated]

Mmode >23dB / Smode >32dB

Mechanical Performance

- subject to termination method and fibre grade


IEC 61300-2-1

10-500Hz 0.75 amplitude @10g acceleration


IEC 61300-2-2

x3000 matings


IEC 61300-2-12

8 Drops (0.9m)

Cable Retention

IEC 61300-2-2

2000N (Cable Dependent)

Environmental Performance

- subject to termination method and fibre grade


IEC 61300-2-8

4000 bumps @ 40g acceleration

Water Immersion

IEC 61300-2-23


Operating Temperature Range

IEC 61300-2-22

-40°C to +85°C

Any questions? Get in touch with a member of the team today.