Gemini Media Interface Adapter

Gemini Media Interface Adapter

Moog Protokraft Gemini series media interface adapters consist of optoelectronic transmitter and receiver functions integrated into a bulkhead mounted MIL-DTL-38999, series III receptacle connector assembly. The optical transmitters are 850 nm VCSEL or 1310 nm FP lasers.

The transmitter input lines are driven with differential CML signals applied to the transmitter (TX+ and TX-) lines. Dual loop, temperature compensated, VCSEL laser drivers convert the transmitter input signals to suitable VCSEL laser bias and modulation currents. The optical receivers consist of PIN and preamplifier assemblies and limiting post-amplifiers. Outputs from the receivers consist of differential CML data signals on the receiver (RX+ and RX-) lines and single ended CMOS indicator functions on the Loss of Signal (LOS) lines. A CMOS fault signal is generated on the TX Fault line by the module controller upon any monitored internal optical or electrical fault condition. The receiver data lines are squelched upon LOS assertion, preventing errant data packet generation when an invalid incoming optical signal is presented to the transceiver. The electrical interface to the Gemini series optical transceiver adapters is a MIL-DTL-38999 series III plug connector with 66 size 22 electrical contacts.


  • Compliant with ANSI Fiber Channel FC-PI / PI-2 and IEEE 802.3:2005 Gigabit Ethernet
  • Compliant with ANSI / VITA 17.1 sFPDP @ 2.5 Gbps
  • Optical fiber link distances up to 550 meters (50 / 125 μm - 500 MHz Km MMF)
  • Maximum optical channel bit error rate less than 1x10-12
  • Operating temperature range from -40°C to +85°C
  • Shock, vibration and immersion resistant per MIL-STD-810 and MIL-STD-1344
  • Olive drab cadmium over nickel plating meets stringent EMI / RFI performance specifications
  • Aluminum alloy MIL-DTL-38999 housings are strong, durable, corrosion resistant and lightweight
  • MIL-T-29504 or LC (SMF or MMF) compliant optical fiber connector interface
  • Sealed against liquid and solid contaminants
  • MIL-DTL-38999 or sealed RJ-45 electrical connector interface
  • Shock and vibration resistant

Note: Other wavelength, mounting and port count options are available.

Typical Applications

Gemini series optical adapters enable high speed network communications over long distances in harsh environments.

  • 10/100/1000Base-T Ethernet switches and peripherals
  • Telecom and datacom switch / router rack-to-rack links
  • Storage or computation clusters