The dormant fiber-optic cables beneath San Francisco will soon awaken. Google parent Alphabet Inc. wants to expand its gigabit Internet service to parts of San Francisco, specifically apartments, condos, and affordable housing units. In most cities Google has wired, the company built its own physical infrastructure to support the service. The company installed network cables in Kansas City; Provo; Utah; and Austin, Texas. San Francisco will require tapping into existing fiber-optic cables. This was also the case in Atlanta, resulting in Fiber service access for fewer neighborhoods than other Fiber cities. But there is also an upside: a much faster path to launch. “To date, we’ve focused mostly on building fiber-optic networks from scratch,” said Michael Slinger, Google Fiber’s business operations director. “Now, as Google Fiber grows, we’re looking for more ways to serve cities of different shapes and sizes.” Google Fiber is already taking this approach in other markets, including Huntsville, Ala., where earlier this year it announced plans to launch using the city’s municipal network. Alphabet’s high-speed Internet service is 85 times faster than the typical residential connection. San Francisco is the 11th U.S. city with existing or planned Fiber service. Single-family homes are not considered for now, because the company wants to serve denser communities first. Also, many of the single-family residences are not close to the existing cables. Alphabet declined to say how many of San Francisco’s homes it aims to serve. As it has done elsewhere, Google Fiber plans to provide free gigabit internet service to “some public and affordable housing properties.”  Google is also working with a non-profit to teach low-income San Franciscans basic internet skills, like how to set up an email account or apply for a job. The fiber network cable doesn’t belong to the city of San...