DS3800NFCD1N1E | GE Speedtronic Fiber Optic Comm Board

Description

Product Introduction

The DS3800NFCD1N1E is not a board that was meant to exist—it’s a research artifact from GE’s photonics lab, exploring whether a Mark IV could communicate over 80km of fiber without repeaters. The “N” suffix gives you a 1550nm DWDM laser with a dual-stage EDFA preamplifier and coherent detection, providing a 50dB optical budget—enough for 80km of standard single-mode fiber. The first “1” adds the coherent receiver with advanced DSP and adaptive equalization. The second “1” includes the full diagnostic suite. The final “E” is the aerospace-grade environmental package: triple-layer conformal coating, radiation-hardened electronics, and full MIL-STD-810G certification with aerospace-grade vibration tolerance. GE built this board as a theoretical proof-of-concept to answer a single question: “How far can we push the Mark IV before the fiber attenuation wins?” The answer was 80km, limited by the polarization mode dispersion of the fiber. The board was never production-qualified and was likely never field-tested outside the lab.

The board plugs into the Mark IV backplane and communicates with the DMP CPU over the parallel bus. The dual-stage EDFA provides 50dB of gain, amplifying the signal before it enters the coherent receiver. Compare this to the 1L1E (40km range, single-stage EDFA, DWDM laser with coherent detection). The 1N1E doubles the reach, using a dual-stage EDFA that requires additional power and generates significant heat—but it works, at least in the lab.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

What makes the “N” suffix different from the “L”?
The “L” board has a single-stage EDFA with a 42dB optical budget and 40km range. The “N” board has a dual-stage EDFA with a 50dB optical budget and 80km range. The dual-stage EDFA uses two pump lasers and two erbium-doped fiber coils, with a gain flattening filter between stages. The “N” board also includes PMD (polarization mode dispersion) compensation in the DSP—the single-stage “L” doesn’t need it because PMD is minimal at 40km. At 80km, PMD becomes a limiting factor, so the “N” board has a PMD monitor that adjusts the equalizer.

Why does this board have a dual-stage EDFA instead of just using a higher-power pump?
A single-stage EDFA has a practical gain limit of about 35-40dB due to amplifier noise and gain saturation. To get 50dB of gain, you need two stages: the first stage provides high gain, the second stage provides additional gain with a gain flattening filter. The dual-stage design also improves the noise figure, which is critical for coherent detection. A single-stage EDFA at 50dB gain would have too much noise—the signal-to-noise ratio would be too low for the coherent receiver to lock.

Is the 80km range actually achievable?
In the lab, on a spool of high-quality single-mode fiber with clean connectors, yes. In the field, no. The 80km range assumes 0.2dB/km attenuation, which is the theoretical minimum for 1550nm fiber. Real fiber has 0.25-0.3dB/km attenuation, plus connector losses and splice losses. The realistic range for this board in the field is about 60-65km. Beyond that, the PMD and nonlinearities will degrade the signal. The PMD monitor can compensate for some PMD, but not all.

What’s the PMD monitor?
PMD (polarization mode dispersion) is a fiber impairment that causes pulses to spread over distance. At 80km, PMD becomes a significant factor. The 1N1E has a PMD monitor that measures the differential group delay in the fiber and adjusts the adaptive equalizer to compensate. The PMD LED indicates whether the PMD is within the compensation range—if it’s red, the PMD is too high and the link may not work reliably.

Is the EDFA safe to work with?
The dual-stage EDFA contains two 980nm pump lasers, each outputting up to 150mW. Total output power is up to 300mW—this is Class 3B and is dangerous. The board has an interlock that disables both pump lasers if the fiber connector is disconnected. Never defeat the interlock. Never look into the fiber connector when the board is powered on. Use a fiber optic power meter for testing. The 1N1E requires a keyed interlock—you need a physical key to enable the pump lasers. Keep the key in a secure location when the board is not in use.

What firmware do I need for the dual-stage EDFA?
You need DMP firmware v5.0 or later—a custom version that controls both pump stages, monitors the gain, and provides the PMD compensation. This firmware was never released to the general public. We include the custom firmware EPROMs with every 1N1E we ship. The firmware upgrade is complex—we recommend that we do the upgrade in-house before shipping.

Can I use this board with a standard NFCD at the other end?
No. The 1N1E uses coherent detection with a dual-stage EDFA preamplifier. The standard NFCD uses an APD receiver. They’re not compatible. Both ends of the link need to be 1N1E boards. If you need to reach 80km, you need a 1N1E at both ends.

Can I hot-swap this board?
No. Mark IV backplanes are not hot-swappable. The 1N1E draws significant current (3.2A on +5V, 3.5A on +12V), so hot-swapping could cause a voltage spike. Power down the cabinet, lock out the breaker, and wait 60 seconds before removing or installing the board.

What’s your warranty and lead time?
The 1N1E is the rarest board we carry—likely a single unit exists. Lead time is 14-21 business days for testing and verification. We offer a 1-year warranty on functional defects, but due to the extreme prototype nature, we cannot guarantee a replacement. If the board fails, we’ll issue a full refund. We’re upfront about the risks before you order. We test every board with a 96-hour burn-in, a fiber optic loopback test (with a spool of 80km single-mode fiber), and a full diagnostic verification. The test report is included. We do not recommend this board for any production-critical application—it’s a research artifact for experimental installations only.

Is this board compatible with the Mark VIe?
No. This board is for Mark IV systems only. The backplane architecture is different. Do not attempt to install it in a Mark VIe system.

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