Coupling coefficients of gain-coupled distributed feedback lasers with absorptive grating

An effective coupling efficient is introduced for gain-coupled distributed feedback lasers with absorptive grating. When radiation and other partial wave coupling effects are considered, the effective coupling coefficient will change significantly. In some cases, it will become real, although both loss and index coupling are presented.

Long period grating for 3-5 mu m quantum-well infra-red photodetectors

By considering all possible high order diffracted waves, the authors calculate the coupling efficiency of long period gratings for 3-5 mu m quantum-well infra-red photodetectors (QWIPs) on the basis of the modal expansion model (MEM). A large coupling efficiency for 3-5 mu m QWIPs has been demonstrated. This greatly reduces the difficulties in fabricating 3-5 mu m grating coupled QWIPs and opens the way to fabricate high performance 3-5 mu m and two colour QWIPs image arrays.

Design and performance of a complex-coupled DFB laser with sampled grating

A complex-coupled DFB laser with sampled grating has been designed and fabricated. The method uses the + 1 st order reflection of the sampled grating for laser single-mode operation. The typical threshold current of the sampled grating based DFB laser is 25 mA, and the optical output is about 10 mW at the injected current of 100 mA. The lasing wavelength of the device is 1.5385μm, which is the +1 st order wavelength of the sampled grating.

A Novel Three-Section Self-Pulsating DFB Laser with Hybrid Grating

A 1.55μm InGaAsP-InP three-section DFB laser with hybrid grating is fabricated and self-pulsations (SP) with frequencies around 20GHz are observed. The mechanism of SP generation in this device is researched. Furthermore, the important role of the phase tuning section on the SP is investigated.

Modified Holographic Exposure to Fabricate Varied Bragg Grating in an Identical Chip

A new fabricating method is demonstrated to realize two different Bragg gratings in an identical chip using traditional holographic exposure. Polyimide is used to protect one Bragg grating during the first period. The technical process of this method is as simple as that of standard holographic exposure

Widely Tunable Sampled-Grating DBR Laser

The 3-section SG-DBR tunable laser is fabricated using an ion implantation quantum-well intermixing process. The over 30nm discontinuous tuning range is achieved with the SMRS greater than 30dB.