Uniform frequency modulation responses in narrow linewidth (<=200KHz) compact hybrid lasers.

Uniform frequency modulation (FM) response is demonstrated using a compact hybrid single frequency, narrow linewidth (=200KHz), semiconductor laser. The hybrid laser consists of a two-electrode gain section, responsible for the uniform FM response, and a narrow band resonant optical reflector (ROR) coupled to the laser, responsible for the narrow linewidth. Uniform red shifted-FM (DC to >=200MHz) is obtained when the section of lower injection current is current modulated. Typical FM dips and phase reversal are observed when injection current to this section is increased. The variation in FM response is attributed to inhomogeneous linewidth enhancement in the two laser sections created by non-uniform carrier injection and thermal frequency modulation.