Data | ELED | ELED | MQW laser diode | VCSEL |
Sample manufacturer
Sample type |
Hewlett Packard
LST500 |
Honeywell
GFE1300-5478 |
Mitsubishi
FS-17LSD |
Honeywell
HFE4080-321 |
center wavelength | 1300 nm | 1300 nm | 1300 nm | 850 nm |
spectral width (RMS.) | ca. 50 nm | 60 nm | ca. 2 nm | 0.5 nm |
bandwidth/rise time | 266 MHz | 200 MHz | 0.3 ns | 6 GHz/0.3 ns |
Threshold current | 2 mA | ? | 3 mA (preselected) | 3.5 mA @ 25°C |
max. drive current | 150 mA | 150 mA | 28 mA | 20 mA |
slope | 0.001 mW/mA | 0.001mW/mA | 0.07 mW/mA | 0.04 mW/mA |
opt. power into 62.5/125 mu multimode fiber min. | 0.1 mW | 0.07 mw | 20 mW | 0.5 mW |
MTTF | ? | ? | 10^8 h | 10^7 h |
data sheet | ? | GFE1300-547 | ? | HFE4080-32x |
cost | 80 US$ | ? | 120 US | 60 US |
Conclusion:
Component | attenuation @ 850 nm VCSEL | attenuation @ 1300 nm laser | attenuation @ 1300 nm with a ELED |
Emitter slope | 0.040 mW/mA | 0.070 mW/mA | 0.001 mW/mA |
Splitter 90:10? | 0.5 dB | 0.5 dB | 0.5 dB |
penetrator | 6 dB | 6 dB | 6 dB |
Fiber 125/62.5 µm | 6 dB = 2 km * 3 dB/km | 3 dB = 2 km * 3 dB/km | 3 dB = 2 km * 3 dB/km |
ST-Connectors | 1 dB | 1 dB | 1 dB |
Receiver | 0.5 A/W | 0.7 A/W | 0.7 A/W |
''efficiency'' | 0.001 A/A | 0.005 A/A | 0,00007 A/A |
Transimpedance of the amplifier converting photo current into voltage | 1 k | 1k | 1k |
This is the signal you get at the output of the optical transmission:
1 pe = 50 mV @ 50 Ohms = 1 mA |
1 mV
(transimpedance of HFBR-2316 receiver is 20 kohms --> 20 mV) |
5 mV
(transimpedance of HFBR-2316 receiver is 20 kohms --> 100 mV) |
70 µV
(transimpedance of HFBR-2316 receiver is 20 kohms --> 1.4 mV) |
Conclusion: Using a laser diode gives at least 12 dB more dynamic range
Transmitter | VCSEL or | 50 US$ |
MQW laser or | 120 US$ | |
ELED | 68 US$ | |
Receiver | 12 x Pin + Pre amp + pigtail + E2000 | 70 US$ |
24 x LEMO | 8 US$ | |
12 x delay lines | 40 US$ | |
1 x PCB (incl. design, contains 12 channels) | 400 US$ | |
12 x set amplifier | 30 US$ | |
12 x sets peanuts | 10 US$ | |
---> | 210 US$ per channel |