Materials science

Refractive index

Optoelectronics

Splitter

Broadband

Telecommunications

Physics

Transverse mode

Optics

Extinction ratio

Computer science

Power dividers and directional couplers

Bandwidth (computing)

Laser

Wavelength

Insertion loss

Grating

Journal of Lightwave Technology

An ultra-compact broadband 2 × 2 3 dB power splitter is proposed and demonstrated by utilizing a subwavelength- grating (SWG)-assisted asymmetric directional coupler. In the present design, a subwavelength grating is inserted into the straight coupling region of an asymmetric directional coupler, so that the refractive index and the dispersion properties of this structure are engineered for achieving an ultra-broad bandwidth and an ultra-compact footprint. For the present power splitter with a straight coupling region as short as 5.25 μm, the bandwidth is as large as 300 nm (1400~1700 nm) for achieving an imbalance of <; 0.4 dB and an excess loss of <; 0.33 dB for the fundamental transverse electrical (TE) mode. The fabricated splitter works well with an imbalance less than 0.5 dB and with an excess loss less than 1 dB in a broad wavelength-band from 1450 to 1650 nm.

Ultra-Compact Broadband 2 × 2 3 dB Power Splitter Using a Subwavelength-Grating-Assisted Asymmetric Directional Coupler