A novel integrated cavity surface emitting laser (ICSEL) is proposed in this paper. An ICSEL integrates two different laser structures. One is an in-plane laser with a short lasing wavelength, and the other is a vertical cavity laser structure with a long lasing wavelength. The in-plane laser is used as the light source for optical pumping the VCSEL. By monolithic integration of both the laser structures, some problems related to electrically pumped VCSELs, especially long wavelength VCSELs, and externally optically pumped VCSELs can be solved.
We reported the nonlinear properties of transfer curves of multiple quantum well (MQW) traveling-wave electroabsorption modulators (TW-EAMs) in analog optical link applications. A new method to extract the optical absorption coefficient of TW-EAMs was developed. By using the method, we investigated the dependence of the transfer curvs on both the input optical power and the bias voltage. The relationships between the RF output power and bias voltage as well as RF input power were studied experimentally and theoretically. A SFDR as high as 128 dB-Hz4/5 was successfully obtained by adjusting the bias level as well as optical input power at 10.0 GHz.
The wafer fusion technique for realization of compact waveguide switches, filters and 3D photonic integrated circuits is investigated theoretically and experimentally. Calculations based on the beam propagation method show that very short vertical directional couplers with 40-220 μm coupling lengths and high extinction ratios from 20 to 32 dB can be realized. These extinction ratios can be further improved using a slight asymmetry in waveguide structure. The optical loss at the fused interface was investigated by comparison of the transmission loss in InGaAsP-based ridge-loaded waveguide structures with and without a fused layer near the core region. This reveals an excess loss of 1.1 dB/cm at 1.55 μm wavelength due to the fused interface. Fused straight vertical directional couplers have been fabricated and characterized. Waveguides separated by 0.6 μm gap layer exhibit a coupling length of 62 μm and a switching voltage of about 12 volts. Since GaAs and InP have different material dispersion at 1.55 μm wavelength, a combination of InP and GaAs couplers is used to demonstrate an inherent polarization independent and narrowband filter.