Efficient and compact green laser for micro‐projector applications

Abstract

Abstract— Efficient and compact green lasers are keystone components for micro‐projector applications in mobile devices. An architecture that consists of an infrared‐producing DBR (distributed Bragg reflector) laser with a frequency‐doubling crystal is used to synthesize a green laser that has high electrical‐to‐optical conversion efficiency and can be modulated at speeds required for scanner‐based projectors. The design and performance of a green‐laser package that uses adaptive optics to overcome the challenge of maintaining alignment between the waveguides of the DBR laser and the frequency‐doubling crystal over temperature and lifetime is described. The adaptive optics technology that is employed uses the piezo‐based smooth impact drive mechanism (SIDM) actuators that offer a very small step size and a range of travel adequate for the alignment operation. The laser is shown to be compact (0.7 cm3 in volume) and capable of a wall‐plug efficiency approaching 10% (at 100‐mW green power). It was demonstrated that the adaptive optics enables operation over a wide temperature range (10–60°C) and provides the capability for low‐cost assembly of the device.

Role of surface roughness and lubricant film thickness in nanolubrication of sliding components in adaptive optics

“…In order to produce a compact green laser, a frequency doubling technique is used with a distributed Bragg reflector (DBR) laser diode, where a 1060 nm wavelength light is passed through a second harmonic generating crystal to produce a 530 nm green laser [1,2]. To correct for any lens misalignment, the green laser module uses an adaptive optics component with a drive mechanism to align the optics and maintain a constant power output with time and temperature [2,3]. The drive mechanism is commonly referred to as the smooth impact drive mechanism (SIDM) (Fig.…”

Nanomechanical characterization of adaptive optics components in microprojectors

“…Schematics of the operation and construction of the drive mechanism are shown in figure 2(b) (Bhatia et al 2009a(Bhatia et al , 2009b. The main components of the drive mechanism are the piezo element, driving rod, moving body and the friction plate.…”

“…The moving body is a U-shaped frame upon which the lens is attached. The driving rod sits in the U-shaped (Bhatia et al 2009a(Bhatia et al , 2009b. frame with friction plates on two sides and is clamped with a leaf spring.…”

“…The net displacement is the minimum movement of the drive mechanism. This is repeated until the desired amount of displacement is achieved (Bhatia et al 2008(Bhatia et al , 2009a(Bhatia et al , 2009b. The full displacement range is approximately 350 μm, and the minimum displacement per pulse is 30-50 nm.…”

“…Figure 2. Schematic of (a) the green laser architecture and (b) the operation of the drive mechanism used in the green laser(Bhatia et al 2009a(Bhatia et al , 2009b.…”