Intermixed InGaAsP MQW tunable laser diode suitable for probing surface plasmon resonance optical sensor
In this work, we demonstrate an InGaAsP multiple quantum well tunable laser diode that amalgamates two gain sections with different bandgap energies. This tunable laser is used as a probing source for an optical sensor that makes use of surface plasmon resonance (SPR). The regions of different bandgap energies are achieved using selective area intermixing of the multiple quantum wells, through impurity-free vacancy induced disordering. By varying the current combination that was injected to each section, the laser wavelength can be effortlessly tuned from 1538 nm to 1578 nm with relatively constant output power. The free spactral range FSR of the tunable laser found to be 0.25 nm. This tunable laser was launched into an optical surface plasmon resonance sensor head that was fabricated on an inverted rib dielectric waveguide to provide an input light source for the SPR sensor. The average sensitivity of the SPR sensor devices was determined to be S = 334 nm.RIU-1.