Companies are increasingly using fiber networking, even to endpoints (computers, servers, printers, etc). One problem with this is that most switches assume copper networking to endpoints and fiber networking to the core. So most switches have 10/100 or 10/100/1000 copper ports with 2-4 SFP or other fiber uplink ports (1G or 10G).
What to do if a company wants to use 100% fiber? You can always consider a modular router – Cisco has long had 24 to 48 port fiber boards that can be installed in 4000 and 6000 series switches. But those are big and bulky (usually) and hardly suited for a small closet that breaks down into endpoint links.
But most 1U “SFP” type switches, where SFP ports take the place of the copper ports, run from 6 to 10 times the price of an equivalent copper switch (even with SFP uplinks). Cisco’s SFP 1U switches include anything with the name form “-12S and “24S”, as in the WS-C3750G-12S or the new WS-C3750X-24S. Inexpensive non-Cisco SFP based 1U/2U switches include Foundry, Dell, HP, and Spherion. All these – Cisco and non-Cisco – are ideal at breaking down core traffic into fiber based endpoint traffic.