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Ask HN: Why is my new residential fiber gateway box so heavy and so hot?

• PaulHoule 4y ago
  I know some passive optical devices depend on precisely spaced gratings which would shift their wavelengths if the temperature changed because of thermal expansion. The easiest way to control the temperature is to keep them in an oven with a temperature somewhat above ambient. I don’t know about customer premises equipment but I see ovens next to telephone poles all the time to maintain the temperature of optical hardware.
  • aurizon 4y ago
    Constant temperature ovens are usually a well insulated box with an ohmic heater and do not emit a lot of heat to maintain their design temperature. Optical stuff is very high in frequency and requires high temp bi directional signal handling. These often need IS's based on ECL - a non saturating logic suitable for this, or possibly other SHF substrate based logic. Non saturating = always on = heat at all times. The whole bi-directional optical amplifier and signal processor can be in the 5-10 watt level. with most wasted as heat which in a small space is substantial.
    • PaulHoule 4y ago
      Generically fast and long range communications consume a lot of power. 10 GBit/s Ethernet has been mature for a long time but you hardly see it in homes and offices because the power consumption is awful, particularly if you imagined what a switch that has 50 ports that are mostly used lightly would cost to run.
• rektide 4y ago
  I've only seen a couple installs but a couple if the units have had builtin battery backup- a medium sized dense lead-acid.