# Is Fiber Optic or Microwave faster?

**URL:** <https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472>\
**Category:** Factual Questions\
**Created:** [February 3, 2003, 11:22am UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472 "2003-02-03T11:22:22Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Dunmurry](https://avatars.discourse-cdn.com/v4/letter/d/d2c977/32.png) [@Dunmurry](https://boards.straightdope.com/u/Dunmurry)\
**Post date:** [February 3, 2003, 11:22am UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/1 "2003-02-03T11:22:22Z")

</div>

Sorry if this seems like a silly question, but in terms of a link between two places, would any one be faster for sending data?  
Say there are two buildings a mile apart would any one a fiber optic cable or a link using two microwave dishes be faster?  
Just wondering.

---

<div class="post-metadata">

**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [February 3, 2003, 11:30am UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/2 "2003-02-03T11:30:10Z")

</div>

It depends on what you mean by **faster**. If you are talking about time delay, then microwave is faster. Light slows down when travelling through a dense medium like fiber optics.

But usually the important parameter is _bandwidth_, i.e. how many bits of data you can send every second. In this sense, fiber optics is much “faster” (transmits more data in a given time).

---

<div class="post-metadata">

**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\
**Post date:** [February 3, 2003, 11:40am UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/3 "2003-02-03T11:40:26Z")

</div>

In air the signal will travel at about 3x10[sup]8[/sup] metres per second. In the fiber, the signal will travel more slowly, typically about 2x10[sup]8[/sup] metres per second.

But over a distance of a mile, that means times of 5.3 microseconds for the microwave vs 8 microseconds for the fiber.

---

<div class="post-metadata">

**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [February 3, 2003, 12:57pm UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/4 "2003-02-03T12:57:02Z")

</div>

Usually microwave transmitters/rec will convert the signal to fiber anyway, this extra conversion step eats some time.

---

<div class="post-metadata">

**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\
**Post date:** [February 3, 2003, 1:36pm UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/5 "2003-02-03T13:36:39Z")

</div>

**k2dave** : Cite? And what’s the propagation delay?

---

<div class="post-metadata">

**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\
**Post date:** [February 3, 2003, 3:47pm UTC](https://boards.straightdope.com/t/is-fiber-optic-or-microwave-faster/152472/6 "2003-02-03T15:47:41Z")

</div>

The question is “faster for sending data.” I don’t think the propagation delay would matter, just the data rate of the two methods. And you haven’t specified what the data rate is. If you have an OC-192 fiber between the buildings (10 gbps), this would certainly be faster that anything you can get with microwave. But you probably don’t have OC-192, since that’s expensive and mostly used for long haul communications. You might have instead OC-3, which is 155 Mbps. What you need to do is find out the details of both systems (their data rates), and compare that.