Monolithically Lens-Integrated Photonic Device Arrays for Compact Optical Transceivers

Abstract

Monolithically lens-integrated surface-emitting distributed-feedback (DFB) laser arrays and p–i–n photodiode arrays were developed. A combination of dry etching and wet chemical etching was used to fabricate a monolithic InP lens. The lens profile within ±10 µm from the lens center was estimated to be parabolic shape, which is ideal for the collimation of a Gaussian beam. A fabricated lens-integrated surface-emitting DFB laser exhibited a circular, narrow far-field pattern with full-width at half maximums of 3.9×3.5°. An efficient direct coupling of the lens-integrated DFB laser to a single-mode fiber with a coupling efficiency of -3 dB was confirmed. A four-channel lens-integrated surface-emitting laser array and a lens-integrated p–i–n photodiode array were used to fabricate a very compact 100 Gbps (25 Gbps × 4 channel) optical transceiver with 14×9 mm2 footprint.

Monolithically integrated 4 ch × 25.8 Gbps lens-integrated surface-emitting DFB laser array directly coupled to SMF

“…Uniform lenses were successfully obtained over all four channels. Moreover, we previously confirmed that lasing characteristics of the LISEL were almost the same as those of the conventional DFB laser, indicating the optical losses at both the lens and the 45°mirror were negligible [9]. Then, it is expected that the chip yield of the LISEL is almost the same as that for the conventional DFB laser.…”

“…3(a)), wet chemical etching was used (Fig. 3(b)) [9]. Here, R can be controlled by changing both the diameter of the lens (D) and etching time.…”

Research Progress of Horizontal Cavity Surface-Emitting Laser

“…In 2013, the Central Research Laboratory of Hitachi Co., Ltd. in Tokyo, Japan, created an integrated photonic device that combined a monolithic lens-integrated SE-DFB laser array and p-i-n photodiode array [64]. The device fabrication process involved dry etching and wet chemical etching to produce monolithic InP lenses with a parabolic shape that facilitates the collimation of Gaussian beams.…”