I quickly setup a simple biasing circuit on a breadboard to check the raw pulse signal from the HRM-2511E sensor. Here's my circuit setup for this test.

I observed the waveform of the raw pulse signal output (Vout) from fingertip on my PC using my Analog Discovery tool from Digilent. The pulse signal waveform has amplitude of a few millivolts as shown below. This waveform was generated by wearing the sensor on my index finger.