Albis Optoelectronics introduces side-illuminated monitor photodiode

March 1, 2005 Rueschlikon, Switzerland -- Albis Optoelectronics, a developer and manufacturer of photodiodes for analog and digital applications, has introduced its PDCS200E, a side-illuminated photodiode designed to monitor the output power of edge emitting laser chips.

Positioned directly behind an FP or DFB laser, the 180-micron thick, side-illuminated laser monitor photodiode receives light emitted from the laser back facet directly through a side facet as opposed to its top surface. No submount is required, as the chip's curved side surface diffracts incoming light directly onto the photodiode active area. The company says this approach eliminates the need for an extra submount.

According to the company, most other optical transmitter packages contain a monitor photodiode that detects the minimal output power available at the rear facet of a transmitter laser chip. When monitoring edge emitting lasers such as FP or DFB laser diodes, a fundamental orientation mismatch occurs between laser light emitted in the horizontal plane, and the upwards facing surface of the photodiode. Most monitor devices therefore require an extra submount to achieve a 90-degree tilt of the photodiode surface in order to detect light coming from the laser back facet.
 
"PDCS200E achieves an excellent responsivity thanks to its curved side facet and large optical aperture. Our concept to monitor diode lasers no longer requires a costly submount with wrap-around electrical leads, thus reducing component count and cost of high-end transmitter packages," contends Markus Blaser, Albis CTO.

"Our side-illuminated monitor diode is the first example of how we integrate additional optical functions into our traditional photodiode products," adds Peter Cairoli, CEO. "This approach substantially reduces the cost of optical modules as these photodiodes can be manufactured on wafer level with high yields."