Deep etching of GaSb/AlGBAsSb layers using a single step, pulsed anodization etching (PAE) method is reported for the first time. A new electrolyte composed of glycol, water, and two acids was used to form the traveling oxide front. The current pulse vs. time data shows an easily measurable change when the etch-front moves through an interface between layers. The PAE process should prove useful in fabricating ridge-waveguide InGaAsSb quantum well lasers.