Fig. 7.
Laser emission wavelength as a function of time demonstrating the stability of the ECL system. (a) Stability measurement results obtained from a PC device fabricated on the UVCP substrate. Solid red and black curves represent the stability measurement results from two sensors with 1 mm distance. The sampling rate is 2 Hz. Alternating rapidly between the two sensors and simple subtraction of the reference (spot 2) LWS from the active sensor LWS (spot 1) results in a short-term stability of 0.39 pm (1σ), as shown in the blue curve. (b) A typical stability measurement result obtained from a PC device fabricated on fused quartz substrate. The quartz-based device has shown improved thermal immunity due to its lower TOC and CTE. A short-term stability of 0.31 pm at a sampling rate of 2 Hz for a 6-minute measurement is shown here without the need of referencing.