Efficient vertical coupling of photodiodes to InGaAsP rib waveguides

Abstract

We demonstrate vertical integration of InGaAs mesa photodiodes with InGaAsP rib waveguides employing an intermediate optical impedance matching layer. The diode length necessary for 90% light absorption at 1.52 μm wavelength was 42 μm, a threefold reduction in diode length with respect to previous work employing similar waveguides without a matching layer. The quantum efficiency was observed to be almost independent of the optical wavelength and polarization. The influence of spatial transient intensity redistribution effects on these devices is investigated in detail.

Quantum-well intermixing for fabrication of lasers and photonic integrated circuits

“…Numerous approaches have been developed for the integration of a laser with an optical circuit; these include evanescent coupling between waveguides and emitting regions (requiring an additional impedance matching layer and regrowth) [29], [30], butt coupling between laser and photodetector (needing a mirror dry etch technique) [31] or the use of surface emitting lasers and photodiodes (requiring high-quality dry-etched mirrors) [32]. For the present work, the use of a simplified, single-growth-step, two section DBR laser, described above [33], [34], represents an attractive solution with respect to both process compatibility and feedback stability for an integrated interferometer.…”

Basic module for an integrated optical phase difference measurement and correction system

“…This process etches Alo.6 0 Ga0. 40 As at about 5000A/min but etches A10.AGaO.6oAs at a comparably negligible rate.…”

“…However, their major drawback is that their implementation requires an epitaxial regrowth of the absorbing detector layer. Another implementation of integrated photodetectors is based on the evanescent-coupling approach [37]- [40]. In this implementation, a vertically integrated structure is used, such that part of the power is coupled into a lossy region where detection occurs.…”

“…60 oGa 0 . 40 As layer. Thus, the IBAE was used to etch up to a depth with in approximately 2000A of the stop etch layer, whereas a selective wet etch technique was used to etch up to the stop etch layer itself.…”

“…60 Gao. 40 As stop-etch layer separating the waveguide and the detector material was needed to assure good fabrication results and has no operational significance.…”