Use of highly overcoupledcouplers to detect shifts in Braggwavelength

Abstract

The authors present a technique for detecting Bragg wavelength shifts using highly overcoupled couplers (HOCC). An HOCC of 60%/nm was fabricated with 626 cycles. With our HOCC, a 5 µW LED and a 95% reflective Bragg grating we were able to detect 10 µstrain (Δλ = 0.01 nm).