Welch first made it possible to commercially deploy reliable 980 nm laser pumps, needed in low noise optical amplifiers employed in dense wavelength division multiplexing (DWDM) telecommunications systems.
[5] From January 1985 to February 2001, Welch served in various executive roles, including Chief Technology Officer and Vice President of Corporate Development of SDL, an optical component company.
[7][8] From February 2001 to April 2001, Welch served as Chief Technology Officer of the Transmission Division of JDS Uniphase Corporation, an optical component company.
[citation needed] Welch is a co-founder, President and a member of the Board of Directors of Infinera Corp, an optical transport networking company.
The Tyndall Award recognizes an individual who has made pioneering, highly significant, or continuing technical or leadership contributions to fiber optics technology.
[18] In 1998, Welch was the recipient of the IEEE LEOS Engineering Achievement Award, presented to him "for the design, development and commercialization of high power diffraction limited semiconductor lasers.